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Michigan Department of Agriculture For an easy to
print PDF version of this page, click here. Integrated Pest Management (IPM) In Food Facilities Prevention of Pests Through Design Preventing Pest Entry to the Food Facility Monitoring a Food Facility for Pests Preventing Pest Problems and Food Facility Sanitation
Pest Birds And Their Management Pest Birds and their Management Field Identification of Domestic Rodents Senses, Ability, and Reactions to Rodents Non-Chemical Management: Trapping
Integrated Insect Pest Management Physical Methods to Control Stored Food Pests Insecticide Use for Insect Control in Food Plants and Establishments Insecticide Application in the Food Plants and Establishments Characteristics And Effects Of Fumigants Factors or Variables Affecting Use Atmospheric Chambers (including trucks, railway cars and ships) Structural Fumigation (by taping and sealing) Safety Recommendations Summary Aeration or Ventilation of Fumigants Additional References and AV Material
The material furnished in this study guide was reproduced from a training manual titled: Gardner, R.D. 1994. Pesticide Application Training Manual for Subcategory 7f Food Processing. Cornell University, Pesticide Management Education Program, 197 pp. MDA desires to thank the manual publisher for their permission to reproduce selected chapters to aid in the training of new sanitarians. The provided information consists of stand alone material, however a core manual (which is the basic training manual for all pesticide applicators) is referenced in places. This manual, which is not provided, can be consulted if necessary. Four (4) of twelve (12) chapters are provided as primary references, and additional two (2) chapters regarding fumigation are presented as optional information should you need or desire information regarding this type of treatment. The following outline is presented along with a summary of contents to aid your review. Integrated Pest Management This chapter provides the means to reduce pest populations through proper facility design, maintenance, and operating procedures. The intent is not to provide entry, food and water to pests who may desire to enter and breed in food establishments. Pest Birds and Their Management Rodents and Their Management Insects and Their Management These sections provide means to identify the common pests found in the United States, and provide effective control options. Many helpful hints are also provided to enhance effective control interventions and proper application of pesticides. Optional Information: Some Characteristics and Effects of Fumigants This chapter provides the basic physics, and chemistry of the commonly used toxic gases commercially used as fumigants in the United States. Methods of Fumigation This chapter provides discussion of the common materials used and their application techniques including important safety considerations. Integrated Pest Management (IPM) In Food Facilities The management of pests in food facilities (food manufacturing, processing, warehousing and service) requires a high degree of professionalism combined with experience and knowledge. As stated in your Core manual, IPM is a process that balances the use of cultural, biological and chemical procedures to reduce pests to tolerable levels. IPM is a systematic approach that considers all reasonable methods to avoid pest .problems. It combines the control or suppression procedures that best suit the particular situation. It is a holistic approach dedicated to removing causes rather than just treating symptoms. The IPM holistic approach basically tells whether or not intervention is needed and:
Realistically speaking, food processing plants are the most highly regulated manufacturing facilities in the country and if pest management is left to an undisciplined, haphazard, non-strategy program, pest levels will certainly exceed thresholds, resulting in stiff regulatory actions. An IPM program will:
Lasting success can be accomplished only when the reasons for the infestation are controlled. There is no magic dust; no single, simple remedy to solve pest problems in a lasting way. Several types of interventions can usually be more effective than only one type, when they are well coordinated so as to have a combined or synergistic effect. Cost/effectiveness is another major consideration that knits together an IPM program and must be assessed on a long term, as well as a short term basis. Prevention of Pests Through Design Pest prevention through design is the engineering science which will help reduce the need for chemical control of rodents, insects, birds and other vermin. This involves landscape design, building design or remodeling, and equipment layout and design. Short grass, neatly trimmed shrubs, paved access ways and proper drainage reduce or eliminate shelter areas for pests. Rodents are further discouraged by surrounding the building foundation with an 18 to 24 inch strip of 1/8 inch pebbled rock in a trench 4 inches deep. This makes an excellent area for traps and bait stations. If the bottom of the trench is lined with 6 mil plastic, weed growth is severely restricted. Building design or remodeling for pest prevention involves building framing, construction materials and building services. When using steel framing, it is very important to keep framing beams, channel stair stringers and other such framing 4 inches or more away from walls, so that inaccessible voids are not designed into the building. Where voids cannot be prevented, they can be filled with polyurethane foams coated with an epoxy filler. Steel, column floor junctions should be grouted and a sloped 60 degrees sanitation cove installed to remove pest cover. Reinforced concrete framing leaves no ledges for dust, but should be free of pits, checks and crevices and sealed and painted where necessary. Concrete is suitable for floors, but will crack and hold dust. Coating the floor will help. The type of service needed will determine the coating used. Before the coating is laid down the concrete must be cured, the surface must be sandblasted, ground or acid etched and primed with the recommended bonding material. Wet processing areas require acid-proof or brick floors for easy cleaning and resistance to erosion. If the floor will be exposed to large quantities of running water or harsh chemicals, the concrete substrate should be protected from erosion with an asphalt membrane over which the tile cement is applied before laying tiles and grouting. Good epoxy or acid-proof grouts must be carefully and smoothly applied to the joints, which should be no more than 1/4 inch wide to reduce water penetration and pest shelter. Non-production zones of food facilities may be covered with asphalt, vinyl asbestos or straight vinyl tiles. These tiles may have cracks or void areas due to incomplete bonding which will harbor insects, so they should not be used in insect sensitive areas. They may also be discolored by pesticides. Old wood floors offer many pest -harborages. When replacing them, store the new flooring materials in the same area. In this way, the new flooring is conditioned to the surroundings and shrinkage and cracks will be reduced. In wet processing areas a rule of thumb is that there be a floor drain for every 400 square feet of floor. Floors should be sloped toward the drain at 3/ 16 inch per foot into a minimum 4 inch sanitary line, which should be equipped with check valves to prevent the entrance of insects and rodents. Wall materials include precast or poured concrete, concrete block, brick, tile and metal curtain. Whatever the material, it should be sealed or repainted and sealed so that it will be easy to clean and so that pores, cracks and failing joints will not offer insects shelter. Be sure that when purchasing hollow sandwich panel-type metal curtain walls, they are well sealed. Do not drill or punch holes in these walls because they make excellent insect harborage. Structural modification occurs in food facilities for a variety of reasons, like a new product line is being marketed or old equipment is being updated. These modifications and perhaps damage to walls results in holes. The holes are potential harborage for pests. A good working relationship with the building engineer or maintenance supervisor will help make repairs occur quicker when walls are damaged. Wall voids can become infested with stored product insects, cockroaches or rodents. To aid in treating wall voids, it is helpful to install short pieces of small diameter PVC tubing, sealed into the wall. These ports can be used to inject insecticide dusts into wall voids. These injection ports should be sealed when not in use. Roofs should be smooth, built-up paper and pitch-type and free of spills and standing water. Pitch and gravel roofs are difficult to clean and corrugated metal roofs can support insect life. Ventilation fans often create problems when they exhaust product dusts onto the roof. Buildups of product dust can serve as breeding ground for insects, and microorganisms, and can attract birds and rodents to the plant. Roof areas around ventilation exhausts should be made as smooth as possible to enhance cleaning of product residues. The fewer windows the better in a food production zone. They are hard to clean and are often opened, allowing pests to enter. Glass-block windows can be used when natural light is desirable in a room. Where glass blocks would be subject to vandals, Lexan sheeting can be substituted, still allowing natural light, but without the breakage problems. Doors should be of metal, have tight fitting seams and any night lights should be located 30 feet or more away from exterior doors so that insects will be attracted away from the doors. Railroad dock sliding doors are particularly difficult to rodent proof, but by use of a channel threshold and proper location of the track splice, a seal can be obtained, but will likely need constant inspection and maintenance. Good lighting with dust-tight fixtures . leads to easy inspection, better housekeeping and better pest control. High intensity sodium lights do not attract insects as mercury vapor lights do, and should be used wherever practical. Wall suspended lockers, urinals and water closets, and ceiling suspended toilet partitions allow wet cleaning of floors. Likewise, water fountains should be wall mounted. Electrical and plumbing services should be installed so that there is adequate access for cleaning behind and through the wall. Pipe insulation should be dense, tough and well sealed and electrical control panels should be either sealed to or held off of the wall. All such panels should be insect proof. Keep in mind that equipment layout and design should be such that it is roomy, easily accessible for cleaning and does not have rolled edges, ledges, dead ends or pockets in which insect-attracting dirt, dust or waste products can accumulate. All equipment should be placed so as to allow at least a 24 inch sanitation line between the back of the permanent equipment and the wall. It should either be raised at least 6 inches off the floor or sealed to the floor with a pliable material that will resist vibration. Pest prevention through good design will vastly reduce the need for chemical control. Preventing Pest Entry to the Food Facility One of the first elements of a successful IPM program in a food facility is identifying how pests enter and making modifications to prevent entry. In any food facility it is far more important to prevent entry of pests rather than wait until they have entered, and possibly established themselves, before taking action. Exclusion of stored food pests is a highly interrelated process. The best results are achieved when the program is designed based upon all the major pests being found, and then expanded to incorporate pests of lesser significance. All pests enter food facilities either as volunteers or as captives. The pests that walk, crawl, or fly into our buildings are the volunteers, whereas those that are carried in with foods or other materials are captives. With this in mind, we are faced with two types of programs. One program, aimed at the volunteers, requires that a full assessment of the plant and continuous monitoring of the grounds and building exteriors be done to seek out and eliminate harborages and food and water supplies. This program component has two parts; reduce potential pest entry routes into buildings and use traps and repellents around normal entrances, particularly those that must be left open for extended periods of time. The IPM program must network with the building maintenance program to obtain the expertise in modifying the structure to reduce pest entry routes. This requires that the pest manager work cooperatively with the building engineer, or maintenance supervisor. Modifying and maintaining the structure to eliminate harborages, and prevent pest entry is essential. The maintenance program is responsible for keeping doors tight-fitting and xxxsing and replacing torn screens on outside doors and windows. Screens should be xxxsing per inch. Air curtains can also be installed to keep flying insects from entering open doors. Air curtains must be of the proper width, have sufficient air velocity to cover from the top of the doorway to the bottom and meet local health code requirements. Maintenance will seal spaces around pipes that can become rodent or insect harborages. Roof ventilation ducts should be covered with hardware cloth to keep rodents and birds out. Cracks in floors and walls should be sealed. Processing equipment may need to be modified to eliminate an insect harborage or allow an inaccessible area to be routinely cleaned. These are just a few examples of the critical role building maintenance has in the IPM program. The second part of the program is aimed at the "captives," and includes the close inspection of all incoming foods and materials, including vehicles, with a clearly defined plan of action to be taken when pests are found. Inspecting ingredients upon their arrival to the plant is another way to prevent pests from entering the plant. Check all incoming supplies, including pallets, outside on your receiving dock. Refuse any shipment of ingredients, linen, or packaging materials in which pests are found, even if there is only one. Bagged or bulk ingredients should be inspected carefully before allowing them to be unloaded. The hatches of bulk tankers can be lifted for inspection. Use a flashlight to check the top of the bulk product. Also check the hatch and its gasket for signs of insects. Trailers with pelletized loads can be inspected with a ht. Look under bags, and inspect the floor of the trailer. It may also be necessary to remove several pallets from the back of the trailer to inspect more of the ingredients.
Monitoring a Food Facility for Pests Monitoring is a systematic survey of the plant at regular intervals that looks at all aspects of the pest situation and maintains data on pest evidence that will help to evaluate the performance of the IPM program. The monitoring procedures will:
In order to meet the high standards of the food industry, extremely detailed inspections and/or monitoring systems are needed to provide the practical working base for the IPM program. Evidence as small as a fecal dropping, egg capsule, or insect carcass should be noted, counted and its location described. Leave no area of the plant or the grounds out of the inspection. When the plant is large, it may be advisable to hire an outside consultant to evaluate the plants' pest levels on an annual or semiannual basis. A new set of eyes will often detect problems previously undetected.
Preventing Pest Problems and Food Facility Sanitation A food facility sanitation program integrates the elements of equipment cleaning, housekeeping and storage practices. An effective sanitation program is another component of the IPM program and is necessary for its success. Depriving pests of food and harborage with good sanitation practices will have a great impact on -the pest population. The quantities of food pests require are small when compared to our own food needs; therefore, cleanup must be complete. Food processing equipment must be kept clean in order, to produce quality food products. Of course cleaning and sanitizing equipment with the wash, rinse, and sanitize sequence will provide control of microorganisms and establish a sanitary food contact surface. However, to be completely thorough, the entire inside, outside, frame, top . and bottom of the equipment must be clean. When processing equipment is in regular use, raw ingredients and product tend to build up on, around and inside the machine. This spillage is normal, resulting from the routine use of the machine. Keep this in mind; all of the pests of food facilities have one thing in common, they do not require large amounts of food. Accumulation of product in the frame or on top of the machine, perhaps even in the motor compartment is food for pests, while the structure of the machine serves as their harborage. A single ball of bread dough the size of a golf ball can support perhaps 30 stored-product beetles for weeks. Other examples can be given, but the bottom line is that all product and ingredient left on the equipment must be cleaned off to prevent pest infestation. Housekeeping Housekeeping is an essential element of an IPM program because it removes food and water the pests need to survive. The housekeeping program must include both the inside and the outside of the plant. Pay attention to the rubbish piles, used equipment storage and trash compactor areas outside. Remove waste food, clean up spillage and trash immediately and keep the garbage storage area clean and the lids tight fitting. As discussed earlier, maintain an 18 inch weed-free zone around the outside wall of the plant. With the weeds gone, rodents and insects are not as likely to harbor there. Weeds at the base of the fence line surrounding the property must also be controlled. Maintain the grounds and ornamental plantings so that they do not become a harborage. Preventive Housekeeping Steps:
There are three basic rules of proper storage for food facilities. The first two are store it off the floor, and away from the wall. Storage should be at least 18 inches away from the wall and on a pallet, rack or shelf. A pest manager will want to inspect all the wall/floor junctions in the plant on a regular basis. With storage away from the wall, a sanitation line is created. This allows the complete inspection of the plant and serves as a safe zone for the placement of pest management devices. Often, this floor area is painted white to help detect dirt, droppings and other evidence of infestation or housekeeping problems. The third rule is the FIFO storage rule that stands for First In First Out. This method of stock rotation helps to reduce-harborage in dry food and nonfood supplies in storage. Applying a receiving date sticker to all incoming ingredients also helps tremendously. The sticker will remain with the shipment and allow for detailed monitoring and compliance with the FIFO storage rule. Thresholds The threshold for action against pests may be determined by economic, medical, or aesthetic considerations. Of course, depending upon the particular pest situation and the institutions involved, sanitary and legal standards also determine pest thresholds. In the food industry, the prevailing philosophy toward thresholds differs from that of some agrarian systems where the coexistence of -a pest population and the commodity is considered necessary to secure some degree of natural regulation of pest population. In most cultures, including the United States, when an insect is found in food, the consumer is not interested in whether the insect is a primary consumer or a "beneficial" parasite or predator. The pest evidence is seen only as a contaminant and as an indicator of further unseen contamination. Therefore, the cultural threshold the food industry strives for is complete elimination of all food industry pests. Pest thresholds are also affected by regulatory requirements intended to protect food from adulteration. Section 402 of the Food, Drug and Cosmetic Act (FDCA) states that "A food shall be deemed to be adulterated if it consists in whole or in part of any filthy, putrid, or decomposed substance, or if it is otherwise unfit for food [section 402(a)(3)]; and if it has been prepared, packed, or held under unsanitary conditions whereby it may have become contaminated with filth, or whereby it may have been rendered injurious to health (section 402(a)(4)]." These two sections explain what constitutes a violation of the Act with regard to adulteration by filth and are the two basic parts of the FDCA under which most domestic regulatory actions are taken against adulterated foods. In layman's terms, these statements mean that the government does not have to prove the food was adulterated to label it so, but only have to prove that it was in a situation whereby it may have become adulterated. Thus, evidence of active or live infestation near a food product may result in a regulatory action such as seizure, prosecution, injunction, recall or a detention relevant to the product that may have become contaminated. Self Assessment or Auditing Programs The food industry has long recognized that an internal self-inspection program is an important part of a successful IPM program. The commitment of the industry to self inspection has been long standing. It helps determine that manufacturing, storage, etc., are in compliance with the Good Manufacturing Practices (GMPS) and the food laws. Industry is equally concerned about protecting the consumer and its own trade name reputation. The size and resources of the corporation generally dictate the size of the self inspection program. The larger corporations may have a well-staffed inspection department. Smaller organizations may be limited to multi-role staff who have inspection responsibilities in combination with others. Some corporations may hire the services of an outside professional inspection service or a qualified consultant. To be effective, the in house inspection program needs the following essential features: 1. Management Commitment. The first and most important requirement is full commitment and involvement by all levels of management. The reporting structure of the inspection group is an indication of the commitment by the company management. This group must report to top management to avoid conflicts of responsibility. All must understand that top management ultimately bears the responsibility for compliance with the GMPS. If this commitment is lacking, even the best personnel, tools and systems will be seriously handicapped, and the programs consistent success unlikely. 2. Qualified Personnel. Inspection personnel need to be academically qualified in environmental health, entomology, microbiology, food science, or those with equivalent experience and specialized training. Other attributes - alert, observant, good analytical judgment, honest, good communication skills. 3. Inspection Tools and Guidelines. Personnel must have knowledge of the quality standards from a regulatory, as well as a corporate point of view in order to determine if the plant is in compliance. Normal tools include, but are not limited to: flashlight, black light (rodent urine) camera, pyrethrurn aerosol, spatula, scrapers, pliers and a magnifying glass. Additional tools include paper and pencil for notes, backpack vacuum cleaner to remove insects as they are found and perhaps a caulking gun to seal cracks and crevices as they are found. 4. Effective Reporting System. The objective of the-reporting system should be accomplished. When compared with a regulatory inspection, the industry report frequently includes recommendations for corrective actions of violations. 5. Effective Follow-up Systems. It has been said that, "You cannot inspect yourself out of trouble." The inspection is of little value if it is not supported by follow-up and corrective actions. 6. Motivational Tools. What motivates people or teams to strive for success in . a job or program varies greatly. Sincere dedication to a task such as a food facility IPM program that by nature is on-going, never-ending and often subject to attention only when things go wrong is difficult to maintain. The dedication to the task must be consistently renewed with positive motivational reminders that the plant must:
Pest Birds And Their Management Feral pigeons, English sparrows, and European starlings are not protected by federal law. A federal bird control permit is not required for programs targeting these three unprotected birds. Black birds, cowbirds, grackles, crows, and magpies are protected under the Migratory Bird Treaty Act. However, Section 21.43, Title 50 CFR, provides that: "A Federal permit shall not be required to control yellow-headed, red winged, Rusty and Brewers black birds, cowbirds, all grackles, crows, and magpies when found committing or about to commit depredations upon ornamental or shade trees, agricultural crops, livestock, or wildlife, or when concentrated in such numbers and manner as to constitute a health hazard or other nuisance;..." States also have laws protecting birds and these should be adhered to, as well as all local permits that are required to kill birds should be obtained before exercising the privilege given by Section 21.43. Pest Birds and their Management There are many species of birds in the United States, but only three, pigeons, sparrows, and starlings, are normally considered pests around food facilities. All three cause problems in cities. All three survive well in close association with humans. They are primarily objectionable because their droppings can be a serious food contaminant. They may also spread diseases. Their droppings deface buildings and their nests plug gutters and cause roofs to leak. Their noise and odor are offensive to many people. They sometimes also carry mites which can bite humans. Pest Birds English Sparrows (House Sparrow)
The English sparrow, a small immigrant also known as the house sparrow, has adapted itself to life throughout the United States and most of Canada. Although their activities are mainly beneficial, they have several habits that are objectionable to humans and need occasional management to protect human health and property. To selectively manage them, it is necessary to understand their behavior and to distinguish them from their distant cousins, the native sparrows, which are protected by law. Description The male English sparrow has a prominent black throat, clear white cheeks, dark gray crown, and a chestnut-colored nape. The female and young are dull gray above, light below, and generally lack distinctive markings. Life History and Habits English sparrows prefer openings or hollows for nesting and will use a ' ny sort of a nesting box, cavity or opening in buildings. Normally, nest building and egg laying begin in early spring - March and April in the northern United States, and somewhat earlier in the southern states. A clutch normally consists of four to eight evenly speckled eggs that hatch in 13 to 14 days. They produce several broods each season and use the same nesting hole over and over again. Generally, English sparrows are gregarious. They nest, roost, and feed together in large flocks. The English sparrow, like our own sparrows and finches, is primarily a seed eater and supplements its diet with insects. It is one of two birds that is able to eat the Japanese beetle. Pigeons
The pigeon is a descendant of the rock dove found in Europe, Asia and Africa. It is believed that it was first brought to this country as a domestic bird in 1606. They have a long history of being raised and kept as domestic birds. The feral or wild pigeons adapt readily to man-made environments and are the most troublesome bird pest in urban, as well as small rural communities. Wild pigeons may live as long as 15 years. While in captivity, they have been known to live 30 years. Description Adult feral pigeons are 6-1 0 inches long, with varied colors. They have a fan shaped tail that is apparent during take off and landing. Their beak points down and the head bobs when walking. The voice is a long, soft coo-oo-oo. One or two white eggs are laid per brood. Breeding occurs year round and peaks in spring and summer. Life History and Habits They feed on seeds and grain, including large kernels such as corn, some fruit, garbage, livestock manure and insects. They may feed on spilled grain, especially along railroads or near storage bins. They raise their brood in unwoven nests made with twigs and often soiled with excrement. Pigeons prefer to live and roost on roofs and high ledges. Ledges are often the preferred location for nests. Starlings
European Starlings were introduced into this country in 1890, and have since expanded their range across the continental United States. Starlings are not protected by federal laws and in most cases not by state laws. State and local laws must be consulted before management actions are initiated, particularly those involving the use of firearms and toxicants. Description Body and wings are gold-flecked, iridescent blue-black when in summer plumage. Winter plumage often includes buff white spots. Starlings have a large spear-like bill that is yellow or olive. They have compact, short, round bodies. The mature birds average 8 1/2, inches long. In flight they can be recognized by their short square tail and their short triangular wing shape. The eggs are bluish-green. Life History and Habits Starlings feed on a wide variety of foods including grain, seeds, and even garbage. Nests are made of stiff, fibrous material lined with fine grass or any soft material. They may nest on eaves, roofs and other structures. They roost in trees, usually far from their feeding area. They may also roost on window ledges during winter in the north central states. Starlings may produce 3 broods per year. Flocks often contain thousands of birds. Sanitation Sanitation is the first step in bird management. Remove sources-of food and water. Garbage should be handled in a manner so that none is available to birds. Spills of grain and other feed should be avoided and cleaned up when they occur. Vacant lots may be a source of weed seed which is also a food source. Sources of water readily available to birds may also attract them. Exclusion Exclusion or building-out to prevent birds from roosting or nesting inside or near the doors of the plant is good bird management. Openings in buildings, behind signs, and under eaves can be screened out with 3/4 inch (1/4, inch for bats) galvanized mesh or rustproof wire. Plastic bird netting is also available for outdoor and indoor applications. In some situations, it can exclude birds from buildings, food or roosting areas. Roost Repellents Roosting on ledges can be discouraged in several ways. Sticky bird roosting repellents can be used on ledges, beams or other areas where birds may roost. The tackiness of these pesticides discourages bird roosting, without entrapping or poisoning the animals. They are initially very effective, but their tackiness is lost with time, usually because dirt and dust accumulates on the chemical. Some of these materials do not work well under extremely hot or cold temperatures. These sticky repellents are available in a variety of forms. They can be purchased as squeeze tubes, aerosol cans, pastes and as cartridges for caulking guns. Electric roosting repellents provide a weatherproof system. A cable is installed in a position to provide the birds with a desirable perch or roosting place. When birds perch on the cable, an electrical charge is created that shocks them away. The birds are not killed. Consult local building contractors, especially those in roofing or insulating businesses or pest control operators experienced in installing these devices. Other repellents that have been used such as revolving lights, noise makers, high frequency sound vibrations or tape recorded noise generally have only temporary effect and, at best, only move birds into another area. Roosting on ledges can be discouraged in several ways. Sticky bird roosting repellents can be used on ledges, beams or other areas where birds may roost. The tackiness of these pesticides discourages bird roosting, without entrapping or poisoning the animals. They are initially very effective, but their tackiness is lost with time, usually because dirt and dust accumulates on the chemical. Some of these materials do not work well under extremely hot or cold temperatures. These sticky repellents are available in a variety of forms. They can be purchased as squeeze tubes, aerosol cans, pastes and as cartridges for caulking guns. Electric roosting repellents provide a weatherproof system. A cable is installed in a position to provide the birds with a desirable perch or roosting place. When birds perch on the cable, an electrical charge is created that shocks them away. The birds are not killed. Consult local building contractors, especially those in roofing or insulating businesses or pest control operators experienced in installing these devices. Other repellents that have been used such as revolving lights, noise makers, high frequency sound vibrations or tape recorded noise generally have only temporary effect and, at best, only move birds into another area. Suppression Suppression or population reduction methods must be performed in conjunction with sanitation and exclusion. Methods of suppression include nest removal, trapping, shooting and chemical control with avicides. Nest removal every two weeks during the spring and summer may greatly reduce populations of English sparrows and pigeons. A long pole with a hook fastened to one end can be used to tear down nests under eaves, rafters , etc. Trapping
Traps can be built from plans obtained from the U.S. Department of Interior or they can be purchased. For possible sources see Appendix A. Several different types of traps can be used. They include funnel traps and bob-type traps for pigeons, rat traps, sieve-type traps, funnel traps, hest box traps and center drop traps for smaller birds such as the English sparrow. Prebaiting prior to trapping for several days increases trap effectiveness. Traps should be supplied with plenty of food and water. One or two decoy birds may help. Trapped birds must be removed daily. Birds which are federally or state protected should be freed immediately if trapped accidentally. Shooting Shooting may be hazardous in some locations and may not be allowed by some local ordinances. It is a very effective means of killing scattered individuals or small flocks. It is best carried out by no more than a few individuals with low powered guns and who understand what they are doing. Where permissible, shooting with a .22 caliber or #1 2 bird shot is effective. Chemical Management Chemical management with avicides or other pesticides -in certain situations may be the only means of effective management. Pesticides may not be used in a manner inconsistent with the label. Decisions as to the need, type of toxicant used and manner in which it is used should be made by professionals. Information on current registered uses of specific compounds is available from the manufacturer or retailer. Sources of up-to-date pesticide recommendations include: industry representatives, the Cooperative Extension Service, local health, environmental and agricultural departments, and technical experts in universities and state and federal agencies. Poisons may be prohibited or may be too risky to use because of the dangers to humans, pets, or desirable birds. Non-target birds are protected by federal, state and local regulations, as well as by public opinion. Identify non-target birds, such as cardinals and doves that may be in the plant area. Select a management procedure that reduces the risk to non-target birds. Carefully monitor the management program to be sure non-target birds are not affected. Label directions must be followed precisely. Avitrol is both a repellent and a toxic bait. Ten percent of the bait is treated so that when eaten by pigeons, starlings, or sparrows, it produces distress reactions in some of the birds. Some may die from the stress or other factors. This frightens the rest of the flock away from the area. Ornitrol is a chemosterilant and is the only pesticide of its type registered for bird management. When the bait is eaten for about 1 0 days it will inhibit female fertility for 6 months. To be successful, two baiting periods per year are necessary. Prebaiting is necessary when chemical baits are used, just as when trapping is to be done. Chemical baits are most effective when used against small flocks and in situations where conditions can be controlled carefully. Shooting may be hazardous in some locations and may not be allowed by some local ordinances. It is a very effective means of killing scattered individuals or small flocks. It is best carried out by no more than a few individuals with low powered guns and who understand what they are doing. Where permissible, shooting with a .22 caliber or #1 2 bird shot is effective. Associated Problems Dry, dusty droppings may contain fungus spores which can cause the human disease histoplasmosis. Workers cleaning such areas, or involved in hand capture of birds, should wear approved respirators. Workers should not smoke, eat or drink anything until dusty clothes are removed and the person washes thoroughly. Ectoparasites such as mites, made homeless when pigeons are removed, may migrate into areas where humans work and live. This can be prevented by treating or dusting nesting or roosting areas as part of the management operations. Any good acaracide can be used if the label directions are followed. Pigeon Management Risks*
Domestic rodents constitute a major pest problem to food industry people. There are three major domestic rodents in the United States; the house mouse, the Norway (brown or sewer) rat, and the roof (black or ship) rat. Rats eat almost everything man or livestock use as food. They contaminate much more than they eat, resulting in products that must be destroyed. Damaged packages must be repaired or replaced. Before you can manage rodents, it is important you can identify the correct species and know its behavior patterns.
Field Identification of Domestic Rodents Characteristics of Domestic Rodents
Senses, Ability, and Reactions to Rodents Well developed in highly sensitive whiskers or vibrissae, and certain guard (tactile) hairs. This highly developed sense enhances their ability to move rapidly in the dark. Rats and mice prefer to run along walls or between things where they can keep their whiskers in contact with side surfaces. Vision Not too well developed. Specialized for nocturnal situations and can detect motion in very dim light. They recognize simple patterns and objects of different sizes. Apparently they are color blind, so any distinctive coloring of poison baits does not reduce their acceptance to rats. Smell Keenly developed sense of smell. Rodents leave odor trails of urine and other secretions which mark trails, delineate territories and detect sexually active mates. Rodents apparently like the odors of most foods eaten by man. They are accustomed to the smell of humans, so human odor on baits and traps does not repel them. Taste Well developed taste but perhaps not as sensitive as in humans. Rats have been observed to detect minute quantities of less than 1 ppm of impurities in foods or poisons. Rodents may reject a bait on the basis of taste or smell alone. Rats associate sickness caused by, poison bait with the bait and not the poison. They prefer fresh food to decayed food. Hearing A keen sense of hearing. Rats hear sounds that humans hear and those beyond human hearing or ultrasonic sounds. Ultrasonics are used in echo location for nocturnal orientation (not nearly as well as bats). Rat pups emit ultrasonic distress signals to recall the mother to the nest. They can locate the source of a noise within 6 inches. Unusual noises cause rodents to attempt escape. Balance Rodents have excellent balance. A falling rodent always lands on its feet. The roof rat even maintains its balance well while walking on suspended wires. Movement Rats and mice memorize the details of their habitat, pathways, obstacles, hiding places, and water and food sources. They learn the muscular movements necessary to move down a pathway to take shelter. This is a sense called kinesthetic sense which is a memory of muscular/physical coordination and aids travel in the dark. When a commonly used pathway is blocked, rodents repeatedly try to negotiate the route that their sense of orientation has informed them should be there. With a running start Norway rats can jump 2 feet, mice 1 foot and roof rats 4 feet. Rats and mice can climb any vertical surface where they can get a claw hold. The extreme feats of climbing and jumping are usually done when under stress. Rodents usually exploit their environment only to the extent necessary; thus rodent proofing work must be planned for what is probable not what is possible. Otherwise, it will probably be too expensive. Reaction to Strange Objects Rats may avoid a new sound or a strange object in their environment for three or more days, particularly if their associates are alarmed by it. Other objects are readily accepted by them (examples: food, garbage). As rodent population pressures build, the rats frequently exhibit "chain-fright reaction" to disturbances. Mice are more likely to explore new objects, and to be caught in newly set traps. Climbing Roof rats and house mice are good climbers, and the Norway rat can climb quite well when necessary. Jumping and Reaching Rats can jump nearly 2 feet vertically, 3 feet with a running start; they can jump 4 feet horizontally, and 8 feet from an elevation that is 15 feet above the finish point. Rats can reach upward about 18 inches. Swimming Rodents are good swimmers. They are able to swim up through floor drains and toilet bowl traps. Competition Roof rats and Norway rats compete when attempting to share space. Norway rats have replaced roof rats in many cities where both were once found. Rats are dominant over house mice. Mice will restrict their activity to time periods when rats are not present. Recognizing Rat and mouse Signs Rats and mice are habitually nocturnal and secretive and are rarely seen during the day except when infestations are heavy. Therefore, it is necessary to interpret signs of their activities properly in order to plan management work. These signs are found in secluded places, such as along walls, under piles of rubbish, and behind or under boxes, boards, and thick vegetation. From the rodent signs, one can tell the species present and whether a rodent infestation is current or old, heavy or light. Droppings Fresh droppings of feces are usually moist, soft, shiny, and dark, but in a few days they become dry and hard. Old droppings are dull and grayish and crumble when pressed with a stick. Runways Rodents select pathways offering the most concealment, best routes of escape and shortest distances to necessary resources. Rats habitually use the same runways between food, water, and harborage. Because of the keenly developed sense of touch in their vibrissae (whiskers) and in specialized hairs along the body, rats prefer continual body contact with at least one vertical surface, such as a fence or wall. Rats also follow "odor trails." Outdoors, their runways are narrow pathways of beaten earth swept clear of debris. Indoors, greasy runways are found along walls, steps, and rafters. Undisturbed cobwebs and dust in a runway indicate that it is not in use. Rubmarks Along regularly traveled runways, a dark, greasy mark forms from contact by the rodent's body. Fresh marks are soft and will smear if rubbed. As the grease ages, it dries and gathers dust and will flake off when scratched with a fingernail. The rubmarks of the Norway rat are most commonly found along runways near ground or floor level, while those made by the roof rat are most commonly seen overhead as swing marks beneath beams or rafters at the point where they connect to the walls. Mice do not leave detectable rubmarks except when the infestation is heavy. Burrows The Norway rat prefers burrows for nesting and harborage; the roof rat burrows only occasionally. Burrows are found in earth banks, along walls, under rubbish or concrete slabs, and in similar places. If a burrow is in use, Rs entrance will be free of cobwebs and dust. Fresh rubmarks on hard packed soil at the opening indicate a well established and presently used burrow. The presence of fresh fragments of food, rodent droppings or freshly dug earth at the burrow entrances also indicates current use by rats. Gnawing Rodents gnaw almost anything they can bite, and theoretically can cut through any material softer than the enamel of their incisors. Norway rat tooth enamel (lower incisors) is rated at 5.5 on Moh's hardness scale. This degree of hardness places the enamel roughly between that of iron and steel. But normally rats will not gnaw anything harder than 3.5 which includes copper, lead, and aluminum. The incisor teeth of rats grow 4 to 5 inches a year, so these rodents must do some gnawing each day in order to keep their teeth short enough to use. Rats also gnaw to gain entrance and to obtain food. When gnawings in wood are fresh, they are light colored and show distinct teeth marks. Small chips of wood or other materials indicate recent gnawing. With age, wood gnawings become dark and smooth from weathering and from frequent contact with the rodent's body. Tracks Fresh tracks are sharp and distinct, whereas old tracks are covered with dust and are therefore less distinct. The tracks of the five-toed rear paws are more commonly observed than. are those of the four-toed front paws, but both may be present. Smooth tracking patches of any dust material, such as flour or talc, placed along runways are of value in checking for rodent activity. To see tracks in the dust, the inspector should hold a flashlight at an angle that causes the tracks to cast distinct shadows. Tail marks are also often visible in dust or tracking patches. Urine Stains Urine will naturally fluoresce under ultraviolet illumination (black light). It will be blue to white if fresh, and yellow to white if old. Commercial black lights are often used to detect rodent urine. The use of black lights is not in truth a guarantee that rodent urine is present. Numerous items will fluoresce when under a black light including optical bleaches found in many detergents and lubricating oils. For positive identification one uses a Brorn Thymol Blue Urease Test. Place the suspected material on Urease-Brom Thymol-Blue test paper. Moisten with water, cover with a cover glass. If a bluish spot appears after three to five minutes it is rodent urine. The most basic fact that a pest manager must know about rodent management is that rodents must have adequate food and harborage to live and to multiply. Therefore, it follows that anywhere there is an abundance of food and harborage there can be an abundance of rodents. Food processing plants, distribution centers, and retail outlets offer rodents an abundance of food and harborage. Removing or reducing available food and harborage with good housekeeping, storage and maintenance practices will have a great impact on the rodent population. Failure to combine the necessary elements of a sanitation program will result in the failure of the rodent management program, in spite of baiting and trapping activities. Housekeeping Housekeeping is an essential element of rodent management because it removes food and harborage for rodents. Good housekeeping enhances the baiting program because there is less food for the rodents to eat and, they are more likely to eat the bait. Even the best baits are not able to compete with other foods. The execution of an effective housekeeping program is even more important when mice are infesting the plant. Their eating habits take them to a variety of feeding locations, nibbling a little food at each. When there is an abundant supply of food, this eating habit can result in the loss of the effectiveness of toxic baits. Rats, on the other hand, require much more food, water and shelter than mice. Do not take this to mean that housekeeping is not important in controlling rats. Housekeeping is the backbone of a successful rat control program, and is usually the difference between a successful and an unsuccessful program. The housekeeping program must include both the outside and the inside of the plant. Pay attention to the rubbish piles, used equipment storage and trash compactor areas outside. Remove waste food, cleanup spillage and trash immediately and keep the garbage storage vessel rodent-proof. Compactors which are self-contained (the ram and storage vessel are one unit) are the most rodent-proof. The vertical compactor with the packing unit on top has less spillage and can hold large volumes of wet waste. Maintain an 18 inch weed-free zone around the outside wall of the plant. With the weeds gone, rodents are not as likely to burrow there and are not likely to linger when on foraging excursions at night. Weeds at the base of the fence line surrounding the property must also be controlled. Maintain the grounds and ornamental plantings so that they do not become a rodent harborage. Once overgrown, the plant grounds become an attractive nesting and burrowing site for rodents. Storage Practices General storage guidelines were given in Chapter 1, but it must be emphasized that eliminating dead or immobile storage is extremely important in the rodent management program. This is considered habitat modification. It removes harborage and hiding places. It reduces carrying capacity, restricting the amount of space available for the rodent to nest, hide or escape. Waste and Trash Management Frequent and regular trash removal is very important to the rodent component of the IPM program. Food waste is very attractive to all types of pests, but especially rodents and often becomes the seeding point for indoor infestations. There are self-contained compactors that have better rat-proofing characteristics than the frequently seen types with a permanently mounted charge unit and removable storage vessel. When the collection company comes to remove the trash, the charge unit and the storage vessel are both removed. This design has very tight tolerances and is very rodent proof. The doors over the opening of charge unit, called a "Dog House," can be tightly closed. They take large volumes of wet waste with no leakage. There are also vertical compactor designs with the charge unit on top. An ozone generator can be connected to the charge unit to control bacteria, keep down smell and inhibit roaches and rats. Maintenance Practices For any food facility, it is far more important to prevent entry of pests rather than wait until they have entered and possibly established themselves. Exterior doors must be tight enough to prevent rodent entry and should have openings no larger than 1/4, of an inch. This is particularly difficult to do if the building has an inside railroad dock, which means that the rail door must close down on top of the rails. The junction of the door and rail will leave gaps large enough for rodents to enter. It will be necessary to regularly maintain the rodent proofing modifications of the rail door. Wooden doors can be penetrated by gnawing rodents. A 12 inch sheet metal kick plate may need to be attached to the bottom of the wooden doors. Some materials that can be used for rat proofing are:
When trapping mice, keep in mind that they do not travel very far, so space them 10 feet apart and use large numbers of traps. In severe mouse infestations, decrease spacing to 6 feet and results may improve. Rats have different habits than mice; one is that they travel farther from the nest, around 30 feet. Traps should be spaced farther apart and must cover the wider range used by rats. Roof rats may be running on rafters, beams and pipes and traps should be fastened there when roof rats are a problem. The odor of dead rodents or human odor on traps will not turn rodents away. in a food operation " keeping the trap clean and free of droppings and rodent hair is essential. These are evidence of infestation and can be considered a potential food contaminant. After capturing rodents, always clean the last remaining evidence from the trap. Here are some final tips for using rodent traps:
Baiting for Mice
The first critically important consideration in baiting for mice is the proper placement of the bait. Baiting needs to be limited to non-processing areas of food facilities. Make as many placements of bait stations as is practical, the more the better with each containing enough bait to feed several mice. With severe mouse problems it has been said that there is no such thing as too many bait stations. Remember mice travel very short distances from their nest, usually not more than 30 feet. Place the stations 20 feet apart along the walls and runways as well as next to all doors. Mice are more likely to enter the bait station if the opening is in their runway and they can see a way out the other side. Place baits between their harborages and where they are finding food. Use mouse-size bait boxes for mice as they are small and more attractive to mice. Bait above the floor level as well because they may be living in the upper reaches of the structure' Smooth the surface of granular baits so that new signs of feeding will show. Examine bait blocks for signs of rodent gnawing, replacing gnawed blocks when found. The gnawing is evidence of infestation and can be cited by an inspector on a sanitation inspection report. Replace moldy, wet, caked or insect infested baits with fresh ones. Remember that any insects in a food facility are detrimental and the insects in infested bait can be cited as a health code violation. The locations of all bait stations should be mapped and numbered on a floor plan. Servicing the stations is quicker and more thorough when a map is available. The program will also benefit as evidence of feeding is collected, summarized and compared with map locations. Pre-baiting may be important. Use several different baits and note which ones they like the best. Keep the baits fresh. Fresh baits are far more attractive and must out-compete other food sources. Lastly, mice usually leave fecal droppings as they eat. These droppings inside the bait station are good evidence for the pest manager, but also for the health inspector. Mouse droppings can be cited in a sanitation inspection and used against the plant no matter where they are found, so remove them from the bait station every time they are found. Baiting for Rats
Several of the mouse baiting strategies are also used for baiting rats. For example; bait stations should be in the rat runway, the openings of the station should be parallel to the runway, place the stations between the harborage and the feeding area, the bait should be fresh and plentiful and use a good tamper proof bait station, but the larger rat size must be used. Baiting needs to be limited to non-processing areas of food facilities. Here are some additional considerations that will help management of rats:
Adjustments must be made to the baiting program if roof rats are to be controlled. Bait stations may need to be placed above the ground level. Secure bait boxes if they could fall and use bait blocks which are wired to the inside of the bait box so rodents can not drag them away. If they do drop on the floor, bait blocks are more easily cleaned up. Tracking Powders Tracking powders are one more form of rodenticide which should be discussed, although their use around food facilities is severely restricted. Tracking powders are rodenticides in a dust or powder formulation. The technical rodenticide is ground to a powder then mixed with inert powders which are used to carry and dilute the rodenticide to a usable concentration. Tracking powders are usually more concentrated than baits and thus, are more hazardous than baits. Tracking powders contain some of the same toxicants as food baits. Warfarin and 11orophacinone are common active ingredients in tracking powders. They are placed so that rodents walk on them and pick up the powder on their feet and fur. Then while grooming, the rodent ingests the toxicant. They are usually not recommended for use in and around homes because of the hazard to children and non-target animals. Their use in commercial food facilities is limited to concealed, inaccessible places. They are not to be used in rooms in which food or feed is handled or stored. They are placed in rodent runways, or are dusted or blown into rodent burrows, wall voids and other inaccessible areas where the rodents frequent. Tracking powders can be used in non-food areas of the facility, applied inside a container, such as a tracking powder station, and then the station is set in the rodents runway. Never apply them where there is a possibility of rodents tracking the powder on exposed food or food preparation surfaces. Fumigating Rodent Burrows An additional chemical management tool for rats and mice is fumigation. Fumigants are poisonous gases that are very acutely toxic to people, pets, rodents and most insects. They are extremely dangerous to the applicator and others if they are not used carefully and properly: Since Chapter X contains very detailed use information about fumigants and fumigation, directions for rodent burrow treatment relevant to this part of the book will be -4iscussed here. Further information regarding personal protection,, handling of the xxxnigant, disposal information and other important details are found in Chapters IX, X and XI. Fumigants can be applied to outdoor rodent burrows only. They can not be used to fumigate burrows that are inside structures or even within 15 feet of inhabited structures. They also may not be applied to burrows which may open. under or into occupied buildings. The fumigation of rodent burrows that are found on the plant grounds can be considered, particularly when rodents have exhibited bait shyness, are wary of traps, or when circumstances suggest that very quick results are required. Fumigation will kill both the rodents and their ectoparasites in the burrow. The primary fumigant for burrows is hydrogen phosphide gas. This gas is produced from two solid fumigant formulations, aluminum phosphide and magnesium phosphide. These fumigants come as pellets or tablets which when exposed to air and moisture slowly begin to release hydrogen phosphide gas. The fumigant pellets or tablets are dropped down into the burrow opening. Follow label directions carefully regarding how many to drop. The burrow is packed with crumpled newspaper or something similar so as to prevent soil from covering the fumigant, then the opening is tightly sealed by shoveling soil over the entrance. If the fumigant is covered, its action will be slowed. Underground tunnels and runways should be treated every 5 to 1 0 feet. Soil conditions are important considerations when fumigating burrows. Lower rates are used in smaller burrows and tight soils under moist soil conditions, while higher rates are used in larger burrows and porous soils with low moisture. This is one reason a range of application rates is given on the label. Treat reopened burrows and fresh runways a second time in I to 3 days after the initial treatment. Wear dry gloves made of cotton if the solid fumigant must be handled. Wash hands thoroughly and aerate used gloves and other contaminated clothing. in a well ventilated area prior to laundering. If stated on the pesticide label, respiratory protection should be worn as well.
Insects are among the most important and most numerous of the pests in the food facilities. Fortunately only a portion of the many hundreds of insect species worldwide can cause serious damage. Many insects are attracted only to deteriorating dried vegetable matter. There are, however, 50 or more that are occasionally serious. Some of the more common and important insects are discussed here. The management of insect pests requires a great deal of knowledge, planning and organization. It can never be a one-time treatment program. As was mentioned earlier in the rodent management chapter, a systematic management approach is needed to obtain satisfactory results. This system consists of these basic parts: inspection and detection, application of a management technique, employee education and a built in follow-up procedure. The object of the program must meet today's high sanitation standards and shoot for the lowest possible level of insect infestation and perhaps total elimination. This objective is necessary to provide the safest food production environment demanded by consumers and government regulatory agencies. Food facility insect management is usually a coordinated effort, targeted against all insect pests. Several general concepts of insect pest management are presented here to avoid duplication. More specific species or family management techniques follow their specific sections. Inspection and detection of insects must be the first priority of an IPM program. A detailed set of notes must be made during the inspection. Each insect found, live or dead, droppings, harborages, sanitation deficiencies, maintenance deficiencies, storage problems and other factors that contribute to the infestation should be detailed in the inspection report. Diagrams of the plant are usually an important aid in his process. These notes will form the basis for customizing the management program. Remember to think like an insect as you are inspecting. For example, if you were a cockroach, you would be crawling with your head and antennae less than one inch from a surface. From this view point it may be easier to see the cockroaches view of the world. Remember their behavior and harborage preferences. Outdoor areas as well as indoor areas must be inspected. Inspecting at night as well as in the daytime is also a good idea. Use traps to help detect insects. Sticky traps placed where insects are likely to be found can monitor the plant 24 hours a day. Record the number of insects trapped, location, species and the body position of the insect. The body position on the sticky trap may point to their direction of travel and thus harborage and/or breeding areas. The most important management technique applied to food facilities is sanitation. Food, moisture and harborage must be eliminated. Sanitation places a significant stress on the insect population, which in turn leads to more effective management. Eliminating harborages usually will need to be coordinated with the plant maintenance crew who will be caulking and sealing them. Close coordination is necessary between the pest management staff and plant maintenance. The absence of a thorough sanitation and harborage reduction program usually results in the over reliance on insecticide treatments. The program then becomes an insecticide treatment program, not an IPM program. Remember that insects can be removed with strong vacuum cleaners with crevice tools attached. This technique will remove adults, immature insects, eggs and pupae. Vacuum cleaners do not discriminate. The more thorough the vacuum cleaner operator is, the more thorough the removal of the insects, and the less reliant the plant will be on insecticide Insecticide applications are part of IPM. Insecticides should be selected and prescribed in coordination with the other management procedures just described. Insecticides are applied against each identified insect according to label directions and the behavior of that insect. The best rule is to first detect and then prescribe a multifaceted attack against the insects that may include insecticide use. Employee education is another critical element of the management plan. Food facility personnel and management can do a lot to assist in the implementation and maintenance of the IPM program. They will, however, need to be educated about the nature of the insects that infest the food facility and also need to be given a few details about how the program works. An appreciation of the IPM program by all plant personnel will lead to a more successful pro ram. All successful insect management programs incorporate follow-up procedures. Follow-up is seeing that a job is done, anything less is hoping. The program must include regular follow-up inspections to evaluate its performance. These inspections will allow continual refinement of the program to adjust, change and improve procedures. Knowledge of insect life cycles is important for proper management. Most of the insects found in food facilities have a life cycle in which (1) the newly hatched insect differs from the fully grown adult primarily in size; the young or nymphs look like the adults in form, except that the wings may not be developed, and they feed in the same places or (2) the adults and young are not alike; the young or immature forms are worm-like, usually called larvae or caterpillars, while the adults are moths, butterflies, flies, or beetles. The damaging stages of insects with this type of life cycle are most often the larvae, which may be found when the adult stage is not resent. Insects with gradual metamorphosis change shape very slowly. Wings develop externally, and as growth takes place, the nymphs look much like the adult.Insects with complete metamorphosis go through four stages of growth. None of the younger stages resemble the adult. There is great change in shape when the adult emerges from the pupal stage. Recognition of insects requires identification of certain features. The illustration below gives most of the names you will need to help you identify them.
Stored Product Pests
There are several important pests of stored food. These pests damage
our food by eating large quantities. What is an even bigger problem is that they
contaminate the food with feces and frass to the point it cannot be sold as human food.
Some species web their food with so much silk that mill machinery may be clogged.
Excessive populations may lead to microorganism problems. Stored Product Insect Pest Management Detecting stored product insects is made difficult by their small
size. Sifting food or ingredients to detect these insects is a very good idea. As the food
falls through the screen, the insects are left behind for identification. While
inspecting, pay attention to insect trails in product dust. These will appear similar to
dog tracks in fresh snow, although smaller. Check the tailings pail at all the sifters for
evidence. Inspect under, around and inside of everything. Lift and move bagged
ingredients; this movement will expose the insect between these packages. Old neglected
product accumulations tend to turn gray as they age. Stir these accumulations looking for
insects. As always, take very detailed notes on what was found and where you found it.
Sanitation is a very important part of managing these insects. Most stored product
pests are small and can survive on very little food. just a dusting of flour is enough to
give the flour beetles food and a place to lay eggs. They are very adaptable, and find
flour, nice, nuts, pasta, dry dog food and spices much to their liking (saw-toothed grain
beetles survive nicely in dry red chili pepper). Product rotation, first in-first out, is
also a critical management procedure. The food facility should be "pest proofed"
to deny flying pests entrance to the facility. Insect electrocutors are helpful when
properly placed and maintained. Non-chemical alternatives must be considered in the management plan. Heat and cold
treatments may be used to kill stored product pests. High temperatures of 120 degrees
Fahrenheit for several hours can be used to kill these insects. Cold temperatures, if
applied very quickly, may also cause mortality if maintained at zero degrees Fahrenheit
for at least one hour. Modified atmospheres, specifically C02, are being used more
frequently in food facility insect management. See the fumigation chapter for details.
Sticky traps which use food attractants or pheromones are also available for stored
product pests. Traps can be used to monitor for the presence of these insects or to assist
in population reduction. Insecticide application should be selected and prescribed in coordination with the
other management procedures. Insecticides applied to cracks and crevices where these
insects hide and live are usually effective. Wall voids, equipment legs, electrical boxes,
and motors and other voids may become dusty with product and eventually infested. Liquid
pesticides should never be applied to electrical boxes as this is an electrocution hazard
and could result in injury. Instead, use insecticide dusts where electrocution is a
potential hazard. Aerosol and ULV treatments with non-residual insecticides should be
applied when the facility is not in operation. Exposed food must be covered or removed.
Exposed food preparation surfaces must be cleaned before use after each aerosol/ULV
application. The pesticide label always provides very specific directions about these
procedures. Always follow them completely. Indian Meal Moth [ Plodia interpunctella ]
This is the most common moth infesting stored food in the US. The larvae feed on a wide variety of rain based foods, seeds, dog food, crackers, nuts, dried fruits and chocolate to name a few. Adults have 4 wings with a 3/4 inch long wing spread. Forewings are gray near the body and reddish with a coppery luster near the tip. The head and thorax are reddish in color. The mature larvae are 1/2 inch long and are dirty white or sometimes pinkish in color. Larvae spin large amounts of silk webbing in and over food. When the larvae are ready to pupate, they leave their food and wander in search of a suitable pupation site. There is an average of six generations per year.
Rice Weevil [ Sitophilus oryzael ]Granery Weevil [ S. granarius ]
The larvae are small, white, legless grubs that feed and develop inside the individual kernels of grain. They may attack grain prior to harvest and in storage. They may also attack grain products which are caked or manufactured into hard items, such as spaghetti, that are large enough for the larvae to get into. The adult weevils are about 1/8 inch long and are dark brown in color. Both have mouth parts that are drawn into an elongate snout. The rice weevil has two pale spots on each wing cover. Its pronotum (top of thorax) has round punctures. The rice weevil can also fly. The granary weevil, on the other hand, cannot fly and does not have spots on its wing covers. Punctures on the pronotum are elongate instead of round. Lesser Grain Borer [ Rhizopertha dominica]
The lesser grain borer is a pest of grain only. The larvae feed on flour, grain dust, and broken or whole grain. The adults are about 1/8 inch long and are strong flyers with small cylindrical, slender, polished, dark brown or black bodies. They characteristically appear to have their head turned downward and have very strong mandibles that can cut through wood. Drugstore Beetle [ Stegobium paniceuml ]Cigarette Beetle [ Lasioderma serricomel ]
Both the drugstore and the cigarette beetle are small, squat, and reddish brown, usually less than 1/8 inch in length. The head on the adult beetle is bent downward and is not readily visible from above. The cigarette beetle can fly and has unlined wing covers. The drugstore beetle, on the other hand, seldom flies and has lined wing covers. Both beetles feed on almost all dried plant and animal material including tobacco, spices such as red pepper, cayenne pepper, ginger and paprika, drugs, grain, dried raisins, and cereal products. They can penetrate most paper packaging materials. Confused Flour Beetle [Tribolium confusum]Red Flour Beetle [T. castaneum ]
Both beetles are considered a serious pest in flour mills. They feed on cereal grains and dried foods including flour, cereal, nuts, spices and many others. Neither beetle penetrates sound grain or most packaging. They may impart a bad odor that affects the taste of infested products. They feed by scraping the surface of foods or by eating finely ground material. The confused flour beetle and the red flour beetle are similar in appearance. Both are elongated, flat, shiny, reddish brown insects about 1/8 inch in length. The only major difference in appearance are the antennae. The red flour beetle's last three segments abruptly enlarge into a club, while the confused flour beetle's last four segments. enlarge gradually. The adult red flour beetle is a strong flier, while the confused flour beetle does not fly. This is the most probable reason that the red flour beetle is found more frequently than the confused flour beetle. Sawtoothed Grain Beetle [ Oryzelphilus surinamensis ]Merchant Grain Beetle [O. Mercator] Both of these small beetles feed on almost all dried foods, such as cereals, flour, dried fruits, chocolate and dried meats. They are able to attack the germ of sound grain, penetrate some food packaging, especially thin wrapping such as cellophane. Adults have six saw-toothed-like projections m the side of the thorax. Adults are 1/8 inch long, elongate, dark brown and flat. The larva is dirty white and less than 3 mm long with a long cigar shaped body. Eggs are placed singly or in groups in the crevices in the food supply, but may be laid freely in foods such as flour. 7here may be six to seven generations per year. The differences between the merchant and the saw-toothed grain beetles are minor. The merchant grain beetle tends to be found in warmer climates. The head must be examined to find a small projection on either side behind the eyes. The one ' important behavioral difference to identify one from the other is that the merchant grain beetle flies, while the saw-toothed rain beetle does not. Rice Weevil [ Sitophilus oryzael ]Granary Weevil [ S. granarius ]Dermestid Beetles [ Trogoderma species ]
Dermestids are several different species of oval shaped beetles, including the black carpet beetle and the Khapra beetle. The Khapra beetle is one of the most serious pests of stored grain worldwide. It was first found in the United States in 1953. Following an investigation of grain storage facilities many infestations of Khapra beetles were found. The insect is considered. a serious enough threat that the area of infestation was placed under a federal quarantine. The distinguishing characteristics between species of Trogoderma are difficult to find. An expert is needed to tell the differences. The larvae of Trogoderma are tapered with the head at the large end. Prominent bristles or hair are often found at the pointed end of the larva. They feed in waste grain, grain dust, flour, powdered milk, candy, dehydrated soup, cigarettes and a number of other items. They can readily penetrate many types of packaging materials. When these insects are present, their cast larval skins can usually be found in or nearby the commodity. Domestic Flies
Flies have had an effect on people and their health for as long as
records have been kept. Some of these have direct effect by sucking blood and directly
injecting disease organisms into the blood stream. Other flies have sponging mouth parts,
such as the house fly, that must feed on liquid food to survive. If a house fly lands on
dry, solid food, R will regurgitate liquid food from its previous meal to wet the new
food, thus contaminating the new food. Flies have been known to carry the organisms of
tapeworm, hookworm, whipworm, roundworm, pinworm, diarrhea, typhoid and cholera. Flies
experience complete metamorphosis with egg, larval, pupal and adult stages. Adult flies
have one pair of wings as adults. Their larvae are called maggots and have the head at the
small pointed end. Their larvae are legless so they. wiggle through the decaying organic
matter on which the eggs are laid. Identifying the many different flies is difficult and
best left to professionals. There are a few that the food facility pest manager should
become familiar with. Domestic Fly Management
Many domestic flies prefer their food wet and lay eggs in wet
decaying organic material., House flies, bottle flies and blow flies all prefer decaying
organic materials, such as garbage, animal excrement or a mixture of soil and garbage in
which to lay eggs. Sanitation is the most basic and critical step to managing these pests
as it should decrease food and breeding sites. The facility areas where wastes are
accumulated, dumpsters, etc. must be cleaned regularly. Garbage pickup should be twice per
week. Trash receptacles need regular washing as flies may find ample breeding media stuck
to the sides and bottom of empty containers. Another good reason sanitation helps manage
flies is that fourth instar larvae- characteristically leave their food and wander some
distance away before they pupate. This behavior removes them from the obvious breeding
zone, into less obvious hiding places for safe pupation. Frequent cleaning, twice a week,
is an ' important, indispensable fly management tool. It is important to recognize the
importance of moisture to flies. Improving drainage will often aid fly management. Paved,
sloped pads for trash compactors should be the rule and not the exception. Repair these
pads as they age. Do not allow them to deteriorate to the point where water can puddle. Maintain building integrity. Tightly screen building windows, roof vents and other
openings with 18 mesh screens. Doors should be self-closing. Freight doors may be
protected with air curtains. Fly traps equipped with bait will supplement other management procedures. Electric fly
traps are also effective. These traps use light to attract flies to a fatal encounter with
a "hot" electric grid. They may be used inside or outside. Proper trap placement
is very important. Remember the trap attracts adult flies. Outdoor traps should be
strategically placed to attract flies away from the facility. When electrocutors are
installed inside, as a rule of thumb, install the trap so that it cannot be seen from the
outside. If you can see the trap when standing outside, so can the flies and will attract
them to the facility. Managing adult flies will often be necessary. Breeding areas off of the facility
grounds often cannot be controlled. Poison fly baits are available and kill flies rapidly.
They must be renewed often as their effectiveness is short lived. Baits are a good
supplement to a management plan, but cannot stand alone. Apply wet baits on fly resting
surfaces outside the facility. Dry baits can be applied outside near trash collection
areas or placed near windows or sunny resting areas. Remember the baits may also be a
hazard to children and pets. Apply them carefully according to label directions. Contact adulticide sprays may also be used, and are applied as fine mists, aerosols,
fogs or thermal fogs. These insecticides give quick knock down and kill the flies
contacted, but give no lasting residual killing action. These applications inside the
facility require special care. Remove or cover all food and ingredients. Cover food
contact surfaces before application. Food contact surfaces may have to be cleaned prior to
facility start up. The pesticide label always provides Very specific directions about
these procedures. Always follow them completely.
Adult house flies are dull gray with four stripes on thorax and about 1/4 inch in length. They are most abundant in the fall but may be found throughout the year. The adult female begins laying eggs only a few days after emerging from the puparium and will lay five or six clusters of 75 to 100 small, white, oval eggs. These eggs will hatch into cream-colored larvae in about 12 to 24 hours. The larvae will grow and pupate in four to seven days at room temperature. Their life cycle can be as short as one week or as long as six weeks. The eggs are laid in animal waste or rotting fruits and vegetables. Rotting waste in garbage cans, compactors or dumpsters is often used as a house fly breeding ground. Blue Blow Fly [ Caliphora erythrocephala, etc. ]
The blue blow fly thorax (area behind the head) is gray with stripes. Its abdomen is shiny blue. They are slightly larger than the house fly. Their life cycle is two to three weeks. Blue blow flies are attracted to decaying flesh and are common during the early spring. Green Blow Fly [ Luciiia sericata, etc.] The green blow fly body is shiny green or copper. They are almost twice the size of the house fly. Their life cycle is two to four weeks. These flies are common during the summer months, often migrating from nearby farms or residential areas. They prefer to feed on decaying fruits, vegetables and garbage, with garbage being a common breeding area. Fruit Fly (Vinegar Fly) [Drosophila melanogaster] Adult fruit flies are about 1/8 inch long and yellowish brown in color. They hover around-ripe or decaying fruits and prefer decaying fruits and vegetables for egg laying. Eggs are often laid on cracks in tomatoes and similar foods. Flies are attracted to sour or pungent odors such as malt vinegar, which can be used to trap these insects. Their life cycle is about one to two weeks.
These are very small (1/25, to 1/12 inch) insects and are usually present in large numbers. The young resemble adults. They normally live in moist areas and feed on fungi. They are usually associated with moldy grain or grain products, and may be carried into food manufacturing plants on infested pallets and cardboard slip sheets. They have been found in newly manufactured empty containers. Their life cycle takes a little over a month to complete and includes egg, nymph and adult.
Spiders and mites are not insects. They have eight legs, two body regions and no wings. Usually they are just a nuisance, but the black widow and brown recluse spiders are poisonous. However, they are rarely found in food facilities. Spiders are more commonly found in warehouses than in production areas. Webs, bodies and excretions of spiders can be a nuisance. Presence of spiders may indicate an insect infestation problem. Mites are extremely small and some may contaminate food. A heavy infestation of mites produces a pronounced pungent odor. Mites may cause skin rashes in humans and digestive disturbances if eaten. Centipedes are not insects. They have many legs - one pair per segment. They are generally considered to be beneficial because they eat insects, but they may also contaminate food. Large populations are associated with moisture and decaying vegetable matter. They usually enter from the outside and may frighten some workers, but are not poisonous. Integrated Insect Pest Management
An IPM program should be dedicated to removing causes rather than
treating symptoms. It requires that the pest manager become a structural ecologist, who
recognizes the characteristic habitats of pests and works systematically to correct the
causes of continued infestations. With all insect pests, the overall goal is to find their
harborage usually within a characteristic habitat. These habitats include, but are not
limited to: Suspended ceilings and false walls Electrical conduit systems Sewage systems (rich in food and water, warm
year round) Heating and AC ducts, utility pipe chases and
large wall openings for utility pipes Hollow modular concrete and steel units
permitting pest movement from wall-to-wall Retrofitted insulation with the vapor barrier
left on the wrong side Steam pipe tunnels and worn or loose-fitting steam pipe insulation Product drying equipment and warm moist-proof
boxes Inside most food production equipment
Neat orderly storage managed with the first in-first out philosophy is crucial to insect management. A complex environment with many varied long-term stored items such as unused equipment, paper goods, wrapping materials, etc. decreases the efficacy of insecticide treatments. Long-term storage reduces cockroach exploratory activity particularly in the darker areas. When the insects are spending 70% of their time in their harborage not exploring their surroundings, they are not likely to contact residual sprays or baits. Storage areas need to be dynamic, moving and not static. New, fresh items in storage or at least moving and cleaning around old items, seems to encourage cockroaches to explore, thus exposing them to our control practices. Good storage practices also include good receiving practices. Preventing hitchhiking insects from entering the facility is done by inspecting materials received before they are brought into the facility. Cockroaches are known hitchhikers on food packages, corrugated cardboard cartons, and burlap sacks of ingredients. Stored product insects rarely enter a facility on their own accord, but usually as passengers in raw or finished product. Excluding pests from the facility is always better than controlling them after they are inside. Pest exclusion of structural and stored-food pests is a very interrelated set of processes. To achieve the best results, the pest manager should create integrated procedures based upon all the major pests being encountered. These processes can be expanded to incorporate the pests of lesser significance. For example, the entry of insect pests can be reduced through the use of self-closing doors, screens, and the use of traps, especially light traps for flying insects. Such practices coupled with a receiving inspection program will reduce the need for using pesticides inside the facility. Exclusion should also mean excluding pests from harborages inside the facility. Sealing cracks and crevices, repairing damaged walls and sealing other ideal harborages such as the tops of hollow block walls is important. Caulking cracks and crevices is more efficient in controlling insects if a crack and crevice treatment (C&C) is performed before caulking. It is usually good cockroach management to seal cracks and crevices. However, there may also be situations in which it would be preferable to leave the cracks and crevices uncaulked and accessible to C&C treatments.
Physical Methods to Control Stored Food Pests High temperature - Heat is used in U.S. flour mills to control insect's with good success. Control is achieved by maintaining all parts of the mill at 122 to 131 degrees F for 10 to 12 hours. Short exposures to high temperatures (greater than 60 degrees C) are also effective. These have been produced by infrared, or radio frequency (microwave) radiation devices. All parts of the product must reach the temperature and be maintained there for the duration of the exposure. Heating of raw grain and flour to control infestations is not without risk of damage to the product, as such exposure may result in:
Low temperature - Insects need warm temperatures to move and to multiply (59-68 degrees F). In the northern climates, winter temperatures are used to reduce the facility temperature below that needed for the insects to reproduce. However, some insects may be able to acclimate to low temperatures and survive. For example, the rusty grain beetle can survive 9 days at -54 degrees F after they were exposed to 59 degrees F for a period of time. Cold can kill insects, but it must be applied quickly. Small quantities of infested commodities can be frozen to kill the insect pests within by moving them into cold storage. Combinations Of C02, 02 and N2 from pressurized steel cylin . ders can be used to control insects. Exothermic generators are also used to remove oxygen and raise the levels Of C02 and N2 to toxic levels. C02 can be applied alone from tanks or by using dry ice. Insecticide Use for Insect Control
in Food Plants and Establishments
Before undertaking insect control in or around food processing with
an insecticide, it is essential to recognize that on August 3, 1973 EPA established some
definitions to assist in the regulation control of insecticides in food handling
establishments. The definitions they use are as follows: 1 . Food is defined by Section 201 (f) of the Federal Food, Drug and Cosmetic Act to
mean (1) articles used for food or drink for man and animals (2) chewing gum and (3)
articles used for components of any such article. 2. A Food Handling Establishment is an area or place other than a private residence in
which food is held, processed, prepared and/or served. a. Non-Food Areas of food handling establishments include garbage rooms, lavatories,
floor drains (to sewers), entrances and vestibules, offices, locker rooms, machine rooms,
boiler rooms, garages, mop closets, storage (after canning or bottling). b. Food Areas of food handling establishments include areas of receiving, serving,
storage (dry, cold, frozen, raw), packaging (canning, bottling, wrapping, boxing),
preparing (cleaning, slicing, cooking, grinding), edible waste storage and closed
processing systems (mills, dairies, edible oils syrups). 3. Non-Residual Insecticides are those products applied to obtain insecticidal effects
only during the time of treatment and are applied either as space treatments or contact
treatments. a. Space Treatment is the dispersal of insecticides into the air by foggers, misters
aerosol devices for control of flying insects and exposed crawling insects. b. Contact Treatment is the application of a wet spray for immediate effect. 4. Residual Insecticides are those products applied to obtain insecticidal effects
lasting several hours or longer and are applied as general, spot, or crack and crevice
treatments. Residuals include the common insecticides, but -also some formulations of
pyrethrins. These are usually thought of as non-residual materials. Certain formulations
with higher than normal concentrations and that are applied as coarse sprays provide
insecticide effects lasting several hours or longer, and are therefore considered residual
by EPA. There are three types of residual applications recognized by EPA: general, spot,
and crack and crevice. a. General Treatment is the application to broad expanses of surfaces such as walls,
floors and ceilings, or as outside treatment. General treatment is allowed only in
non-food areas, using only those insecticides that are registered for such use. A barrier
treatment is also considered a general treatment and is applied to entrances, the
foundation and soil adjacent to the foundation. Read and follow the label as some
pesticides contain explicit instructions for this use. Some outdoor insects or related
pests may become an invader or nuisance when populations build up. A barrier treatment
with residual sprays, dusts or granules may be beneficial in controlling the pest. b. Spot Treatment is the application to limited areas on which insects are likely to
occur, but which will not be in contact with food or utensils and will not I ordinarily be
in contact with workers. These areas may occur on floors, walls, and bases or on the
butside of equipment. For this purpose, a "spot" will not exceed 2 sq. ft. Until
recently, this application could be used only in non-food areas. However, some
insecticides have received EPA approval for label directions permitting spot applications
in food areas. These directions will appear on the labels of other insecticides as EPA
approves them. c. Crack and Crevice Treatment (C&C) is the application of small amounts of
insecticides into cracks and crevices in which insects hide or through which they may
enter the building. Such openings commonly occur in expansion joints, between different
elements of construction, and between equipment and floors. These openings may lead to
voids such as hollow walls, equipment legs and bases, conduits, motor housings, junctions
or switch boxes. The crack and crevice treatment includes the use of sprays, dusts, or
baits. It permits the use of products in food areas as long as the insecticide is placed
only into cracks and crevices. It does not permit treatment of surfaces. Residual insecticides may be applied when the food establishment is in operation,
unless the label of the pesticide specifically indicates that all operations must be
stopped. Non-residual insecticides when used as space treatments (ULV, ULD aerosol and fog
treatments) should be made while the facility is not in operation; exposed foods must be
removed or covered. All food handling surfaces must be cleaned before use following a
space treatment. If a non-residual insecticide is used as a contact treatment (review
definition), the treatment can be made while the facility is operating. Space treatments
and contact treatments are both considered to be general insecticide applications. Insecticide Application in the Food Plants and Establishments
Characteristics And Effects Of Fumigants
A fumigant is a pesticide chemical, that at the proper temperature,
is in the gaseous state in a high enough concentration that it will be lethal to the pest
organism. Fumigants can penetrate almost any material and are lethal to a wide spectrum of
pests. The most important part of the previous definition is that the fumigant is a gas.
Gases exist as single small molecules that can move into very small gaps, such as between
the particles of a concrete block or the fibers of wood, or through small openings in
equipment, or between kernels of grain. This is the only form of pesticide that can
penetrate into hollow block, brick walls or other protected areas. Fumigant gas molecules
penetrate so well that they must be confined in an enclosed space to be effective. As soon
as the fumigant escapes from the enclosure its effectiveness is lost and reinfestation can
occur. In contrast, smokes, fogs and aerosols are dispersions made of very fine particles or
droplets and are not considered gases. Thus, smokes, fogs, and aerosols are sometimes
mistakenly called fumigants, but they are not true fumigants because they are not gases.
The movement of fumigants can be predicted by understanding a few laws of physics. For
example, gases move from an area of higher concentration to an area of lower concentration
until there is equilibrium. The speed of gas movement is affected by temperature; slower
when cold, faster when warm. Knowing the nature and effects of fumigants is a must before
the pesticide can be applied safely and effectively. Toxicity and Hazards
Fumigants are usually highly toxic. They act fast and may be
odorless and cannot be seen. Some fumigants are flammable and under the wrong conditions
can be explosive. Fumigants are dangerous materials. No one should undertake their use without thorough
training and adequate precautionary measures to protect life and property. It is essential
that the person applying fumigants has a complete understanding of safe and effective
techniques before attempting any fumigation job. When training and precautions have been
taken and followed, the hazards of the work are greatly reduced and the results are highly
effective.
Disadvantages
Some disadvantages of using fumigants are that: They can be highly toxic to humans, animals
and plants They require more specialized protective
equipment, such as gas masks, leak detectors, etc. They require highly trained applicators They have no residual effectiveness after
aeration They require the complete and tight enclosure
of the commodity or area to be treated Some may injure seed, reducing germination,
and/or leave toxic residues, tastes, or odors Because they are fast acting, the response to
problems and emergencies must be quick Some are expensive, corrosive, or may leave
residues They usually require obtaining special
licenses or permits Temperature requirements may be hard to meet,
especially in northern climates Factors or Variables Affecting Use
Many factors affect the use and effectiveness of fumigants. The,
stage of development and activity of the target pest is important. Active adult insects,
for example, are easier to kill than inactive or hibernating adults. Immature insects
generally require higher dosages or longer exposure than adults. The amount of free or
open space in the area to be fumigated, the temperature, the porosity (having pores that
permit liquids or gas to pass through) of the product, the kind of product, the location
of the pest within the product, and the type of structure to be fumigated all affect
dosage and exposure periods.
ESSENTIAL PROPERTIES OF FUMIGANTS IN COMMON USE FOR INSECT CONTROL
*TLV-TWA: Threshold Limit Value-Time Weighted Average concentration for a normal 8-hour workday and a 40-hour workweek, to which nearly all workers may be repeatedly exposed day after day, without adverse effect. All methods by which fumigation may be accomplished have one factor in common some means to hold an adequate concentration of the fumigant for the time necessary to obtain pest control. These various methods are: vault fumigation, including vacuum chambers, atmospheric chambers, trucks, railway cars, ships and buildings, tarpaulin fumigation, which may be accomplished under a tarp indoors, outdoors, or by covering the entire structure, and spot or local fumigation. Vault Fumigation
Vault fumigation is referred to in this manual as including any
structure of a permanent nature in which fumigation may occur, as opposed to specialized
vaults such as vacuum or atmospheric chambers used only for fumigation. Vacuum Chambers
Vacuum chambers differ from other forms of vault fumigation in that
the fumigation is conducted under vacuum rather than at atmospheric pressure. Vacuum
chambers are large steel structures. One common chamber is built in sets of two, each is
50'x 6'x 8'. Frequently they are equipped with fans or recirculating systems. By using a
vacuum, the fumigation time can be reduced from 12 to 24 hours, down to 1-1/2 to 4-1/2
hours. The vacuum denies oxygen to the pest and facilitates rapid penetration of the
commodity by the fumigant. By adding an air-wash cycle (breaking the vacuum and drawing a
second vacuum), aeration is also rapid. Vacuum fumigation chambers are usually found at
port facilities and near large warehousing operations. Methyl bromide is the gas most
frequently used. Aluminum phosphide cannot be used because phosphine is explosive under
vacuum conditions. There are two main methods of conducting vacuum fumigation: sustained vacuum and
restored pressure fumigation. In the sustained vacuum method, the pressure is reduced, the
fumigant is introduced- and the slightly reduced pressure or vacuum is held until the end
of the fumigation period. In the restored pressure method, the pressure is lowered and restored in one of several
ways. Gradual restoration of atmospheric pressure The fumigant is released and air is slowly
introduced until it is just below atmospheric pressure after 2 or 3 hours. Delayed restoration with the vacuum being held for about 45 minutes following discharge
of the fumigant, after which air is allowed to rapidly enter the chamber. Immediate restoration following introduction of the fumigant by rapidly letting air
into the chamber by opening one or more valves. This method has been widely used in this
country for baled cotton. Simultaneous introduction of air and fumigant in which special metering equipment
allows a mixture of air and fumigant into the chamber. At the end of any of the methods, air-washing is carried out. It consists of removal of
the fumigant/air mixture and the chamber is then flushed with clean air several times
until it is considered safe to open the door for unloading. The disadvantages of vacuum fumigation include the very expensive initial investment,
and the need to move the commodities into and out of the chambers. It cannot be used with
certain tender plants, fruits and vegetables which cannot withstand reduced pressure. Portable Chambers
A portable fumigation system, developed by B & G Equipment
Company, Plumsteadville, PA, brings added flexibility to an applicator who may need to
fumigate small quantities of items or commodities in various locations. The components of
the system are: Two pieces of heavy duty vinyl sheeting that
can be zipped together, similar to food storage bags Fumigation dispensers Connecting hoses Security lock Gas concentration monitoring valve Carrying Case Gas discharge stand pipe The system is designed to allow the operator to develop a vacuum inside the bubble. The
vacuum will pull the flexible bubble around the commodity. After collapsing the bubble,
the fumigant is applied. Normal safety precautions are necessary, including, a
self-contained breathing apparatus (SCBA) and monitoring tools to test for leaks. Atomspheric Chambers (including trucks, railway cars and ships) Atmospheric Vaults or Fumigation Chambers These are usually small buildings located well apart from other structures. Some are specially built for fumigation, others are modified from other structures. Once an atmospheric vault has been built or modified for fumigation, it can be used again and again. Concentrations can be monitored through a permanent arrangement. Commodities are easily moved in and out of the vault without special preparation. The fumigator does not have to compute the volume of the structure each time the fumigation will take place. Special preparation of the X commodity, such as padding corners, is not necessary. Almost any fumigant can be used. While safety precautions must be observed, fewer considerations are necessary. In addition to the initial cost of setting up a fumigation vault, the disadvantages include; cost of moving the commodity to and from the chamber, the limited quantity of items that most vaults will hold, and the economical utilization of the facility. Trucks (Stationary) and Freight Cars (Stationary or in Transit) Stationary trucks and freight cars are also, examples of "vault" fumigation. These vehicles must be well constructed and in good repair. If they are not, they must be made air-tight or the entire vehicle must be tarped so that the fumigant, can be retained for the fumigation period. Movement of the freight car or truck during the fumigation may result in loss of the fumigant. An exception to this is in-transit fumigation of railcars using aluminum phosphide. PH3 (phosphine, hydrogen phosphide) is the only fumigant registered for in-transit fumigation. As hydrogen phosphide continues to be generated, a low gas concentration is maintained. See pages 125 and 178 for details for railcar treatment with metal phosphide fumigants. Fumigation of wheeled carriers is often convenient and economical in both time and labor by avoiding extra loading and unloading. It not only controls the pests in the commodity, but also in the vehicle so that live pests do not remain behind after unloading. Fumigation of incoming loads prevents the introduction of pests into clean areas. It is not legal to move goods under fumigation or incompletely aerated over public roads or highways. Structural Fumigation (by taping and sealing) This is essentially a modification of vault fumigation. No tarp is used and the entire structure becomes a fumigation vault. The building must be of the proper construction (brick, concrete, stucco, etc.) for a tape and seal fumigation. The roof may need to be tarpped if its construction alone will not provide a leak free barrier. By using this method, only those building contents which could be damaged by the fumigant need to be moved. Incidental control of non-target pests is usually obtained. Less material is needed to make the structure air-tight, but this advantage is usually offset by the labor required to find and seal gas leaks. Exterior shrubbery usually does not need to be moved. There are also many disadvantages. The occupants must be moved from the structure. Items that may be damaged by the fumigant must be moved from the structure. The fumigant may diffuse through the wall, and it may be-difficult to maintain the required gas concentration. The building may be more difficult to aerate than a tarp job. By the nature of its construction it is tight and will not lose gas through walls. Insects in the exterior walls may not be controlled because the gas concentration may be too low to be effective. Also, the eaves will not be fumigated as the gas will not penetrate to those building areas. Gas concentration test leads must be run throughout the structure and the gas concentrations monitored. It may be difficult to compute the cube of the structure. It is very easy to overlook vents, cracks, conduits, etc. that may permit the gas to escape. Premise Inspection
Once it appears that fumigation will be required to control a pest
problem, make an in depth on-site inspection. Ask yourself a number of questions and make
a number of decisions. Frequently, the success or failure of the fumigation operation will
depend upon what you learn, what you decide, and how you plan. Some of these questions
should include: If the structure itself is not infested, could the infested items or
commodity be moved from the building or trailer and fumigated elsewhere? Assuming that
removal of the infested items from the building is not practical, can you fumigate them in
place? Is there enough room between the commodity and walls or partitions so that you can
seal the tarp to the floor? What is the cube (cubic feet or volume) of the commodity? What
is the cube of the building? Can the structure be made reasonably airtight, or will it be
necessary to tarp the entire building? With what construction materials is the structure built? (Fumigants will pass through
cinder block and wood with no difficulty). Are there broken windows that must be replaced?
Are there cracks in the ceiling, walls or floors that must be sealed? Are there floor
drains, sewer pipes or cable conduits that will require sealing? There have been a number
of fumigation failures because floor drains under stacked commodities went unnoticed. In
one instance, the fumigant leaked into a telephone cable tunnel which led to an occupied
building and a number of people became ill. How are you going to handle air conditioning
ducts and ventilation fans? Are there fireplaces, flues, or stove pipes? Will interior
partitions interfere with fumigant circulation? Are the interior partitions gas tight so
that they can be relied upon to keep the fumigant from entering other parts of the
structure? Are there parts of the building not under the control of your customer? Can these other
operations be shut down during the fumigation? What are the building contents? Can any of
them be damaged by the fumigant? Can such items be removed during the fumigation? If they
cannot be removed, can they be otherwise protected? Where are the gas cut-offs? Where are the pilot lights? Where are the electrical
outlets? Of what voltage are they? Will the circuits be live during fumigation? Can the
outlets be used to operate your fumigant circulating fans? Look outside the building. If you tarp the entire structure, can you make a good, tight
ground seal? Is there shrubbery next to the building that might be damaged either by the
fumigant, or by your digging to make an airtight fumigation seal? Can this shrubbery be
moved? How far is it to the nearest building? Does that building have air conditioning?
Does it have air intakes that could draw the fumigant inside-particularly during aeration? How are you going to aerate your structure after fumigation? Are there exhaust fans,
and where are the fan switches? Are there windows and doors that can be opened for cross
ventilation? Does the building contain any high priority items that may have to be shipped
within a few hours notice? Is the structure to be fumigated located so that your operations may attract
bystanders? (If so, you should consider asking for police assistance to augment your own
guards). Where is the nearest medical facility? What is the telephone number of the
nearest poison control center? Once you are convinced that you have covered everything, prepare a checklist of things
to do and of materials needed. Don't rely on your memory. Then finally, two questions:
What have I overlooked? Is fumigation still the best method of controlling the pest
problem? A sample checklist for fumigation building inspection is presented on pages 142 and
144. Tarpaulin Fumigation
Tarpaulin fumigation involves the placement of a gas-tight material
over the commodity or structure to be fumigated. The tarps may be specially made for
fumigation, such as impregnated nylon, or they may be sheet polyethylene. Impregnated
nylon tarps may be used again and again as they are very strong and resist ripping. Many
sections of impregnated nylon tarps can be clamped together, so there is no limit to the
size of the stack or structure that may be covered. Polyethylene tarps can be used in
thicknesses from 4 mil up to 6 mil. The thinner material can be used once and is for
indoor work. Four and six mil material can be used outdoors, and possibly, the 6 mil
material can be reused. As clear polyethylene breaks down in sunlight, black polyethylene
films may be used outdoors. Use gas impervious adhesive tape instead of clamps to join
various sections of polyethylene film together. In addition to considering the material to
use for tarpaulin fumigation, consideration must be given to the method of obtaining a
ground seal. If they are smooth, concrete and asphalt surfaces are satisfactory. Wood
surfaces are not. With wood, and frequently with soil surfaces, it is necessary to place a
section of the tarp material beneath the stack as well as over it. There are several methods of obtaining a good ground seal. Of course, you must allow
enough tarp material to skirt out from the stack. This should extend outward at least 18
inches. Then loose sand, sand snakes, or water snakes are used to hold the skirt to the
ground surface. Snakes are merely tubes of cloth or plastic filled about 1/4 full with
sand or water. Don't fill them too full or there will not be enough ground contact to make
a good seal. A word of caution about using water snakes; if the floor is not level, the
water will run to one end and the seal will be poor. The snakes should overlap each other
about 1 1/2feet. Sometimes it is easier to use adhesive tape and make a direct seal to the
floor. In this case, snakes are not needed. Occasionally, you may find a stack placed too
close to a wall to obtain a good ground seal. In this case, move the stack and seal the
tarp properly to the floor. Indoors
If it is determined that a stack of items is infested and requires
fumigation, it is best to conduct the operation indoors. Indoors, the stack is protected
from wind and rain. If for safety, or other reasons, the storage area is not suited for
fumigation, then it is better to move the commodity to another indoor location rather than
to fumigate outdoors. You will have determined this when you first inspect the structure.
The commodity to be fumigated should be on pallets. With most fumigants, it will be
necessary to keep all persons not associated with the Jumigation operation out of the area
where the fumigation is being conducted. The entire building should be evacuated. If you
are using aluminum phosphide, these restrictions are not as rigid. With aluminum
phosphide, after the fumigant is introduced, work can continue in the area as long as you
are sure that there is no fumigant leakage. Of course, warning signs must be posted on the
stack and monitoring must be done regularly. If you are using any fumigant except aluminum phosphide, you will have to erect tarp
supports which are one to two feet higher than the stacked commodity. This is to make
certain that there will be adequate circulation of the gas during the initial stages of
the fumigation. The gas introduction tubes should then be secured to the top of one of the
supports. A pan or other device should then be placed beneath the gas introduction tube
outlet to protect the commodity from any liquid fumigant. Next, all of the corners must be
well padded to prevent the tarp from tearing. The lighter the polyethylene tarp, the more
chance there is for tears. If the stack is large, non-sparking fans must be placed so that
gas circulation will be assured. These fans must run for one-half to one hour after the
introduction of the fumigant. You must also run tubing from various positions in the stack
(usually, one located high- in the stack, one at an intermediate location, and one at a
low location) to the position where you will be sampling the gas concentration. After all
of this is done, the tarp can be placed and sealed to the floor. Because of the molecular
activity of hydrogen phosphide, the air dome, tubing and fans are not necessary if you are
using aluminum phosphide. Of course, you will have to obtain the cube of the space beneath
the tarp so that you can calculate the amount of fumigant to use.
Spot fumigation may be defined as the short term treatment of processing machinery and equipment with toxic gases for control of the pests which infest food and feed particles remaining within the equipment. These spot treatments are usually intended to interrupt the life cycles of insect pests. Since one or more life stages may survive this short term treatment, spot fumigations must be repeated periodically to control the insect infestation. Spot fumigation can be used to control stored product insects in bins, silos, holding tanks, elevator boots and heads, filters, conveyers, spouting, purifiers, food processing equipment, sifters, rollers, dusters and related equipment in mills, food and feed processing plants, breweries and similar industries. Application of the fumigant usually occurs where there is an accumulation of static or non-moving stock. Such places include:
The only fumigant currently registered for spot fumigation is magnesium phosphide. Sold under the trade name Magtoxinâ Prepac Spot Fumigant, this formulation has been specially manufactured for the treatment of food and feed processing machinery and equipment. The Magtoxin Prepac Spot Fumigant consists of a gas-permeable blister pack of Magtoxin Pellets. Each Magtoxin Prepac strip is roughly 4-1/4-1 1 x 16" and contains 33 blisters, each blister containing 2 pellets for a total of 66 pellets per strip. Magtoxin pellets weigh approximately 0.6 grams each and release 0.2 grams of hydrogen phosphide gas. Magtoxin also contains ammonium carbarnate which liberates ammonia and carbon dioxide. The ammonia serves as a warning agent. Upon opening the aluminum foil pouch, atmospheric moisture penetrates the porous fleece material on the top and bottom of the Prepac strip. The pellets then begin to react to produce small quantities of hydrogen phosphide gas which diffuses out through the fleece into the surrounding space. This reaction starts slowly, gradually accelerates and then tapers off as the magnesium phosphide is spent. The rate of decomposition will vary depending upon moisture and temperature conditions. For example, when moisture and temperature are high, decomposition may be complete in less than 10 hours. However, at lower ambient temperatures and relative humidity levels, decomposition may require 4 days or more. After decomposition, a dark gray powder composed almost entirely of magnesium hydroxide and other approved inert ingredients will remain. This powder will be retained inside the fleece of the Prepac strip. The spent Prepac must not be allowed- to contaminate the processed food or feed. Therefore, it must be retrieved after fumigation prior to starting up the processing line, unless the spot fumigant has been applied to a furniport or in some other fashion to ensure that it is retained and will not enter the food or feed stream. If properly exposed, the spent Prepac will normally contain only a small amount of unreacted magnesium phosphide and may be disposed of without hazard. The spent Prepac is not considered a hazardous waste. However, partially spent residual from incompletely exposed magnesium phosphide will require special care. These instructions are detailed in this manual under hydrogen phosphide fumigant disposal and on the product label. Safety Recommendations Summary
At least two trained persons must be present during spot fumigation of food and feed processing machinery and equipment. Two trained persons must also be present during reentry into fumigated and/or partially aerated structures or rooms housing treated equipment. Do not fumigate food processing machinery or equipment with hydrogen phosphide when air temperature is below 40 degrees F (5 degrees C). The minimum duration of the spot fumigation is 34 hours. This exposure period serves not only to control the infestation, but to allow ample time for reaction of the solid magnesium phosphide. The most important aspect in spot fumigation is a thorough understanding of the equipment and all of the various product and air flow patterns. The fumigator should review schematics and/or diagrams of the facility and a walking survey should be conducted to inspect the food processing machinery and equipment. The site and equipment inspection must determine if the machinery and the site to be spot fumigated can be made sufficiently gas tight. Then a plan should be developed to provide for proper and efficient application of the fumigant. This plan must include emergency monitoring procedures so that they can be conducted to prevent excessive exposures. An overall plan for the spot fumigation should be developed to include the following items:
All application points should be plainly marked, particularly where ladders must be used in reaching overhead areas where the application point may not be visible from the floor level. A checklist, or chart, should be prepared for each plant, showing the location and number of application points on each floor. As each point is treated, the appropriate location should be checked on the chart to be certain that no points were missed before moving to the next floor. Prior to application of the fumigant, run the machinery to empty the process stream and remove dead stock where possible. In the mills the feed should be cut and the mill allowed to run for 30 to 45 minutes to remove as much stock as possible. During this period, rubber mallets should be used to tap on spouting, elevator legs, and sifters to loosen as much residual stock as possible. Outlet channels in sifters should be checked at this time to be certain that they are not blocked or choked. Seal all equipment to which the spot fumigant will be applied. Eliminate drafts inside the equipment by closing off sections which have openings. Take any other steps necessary to prevent air movement inside the equipment. Seal all openings with tape, tarpping, etc., to prevent escape of hydrogen phosphide into rooms housing the equipment. All dust collector vents should be sealed using polyethylene sheeting or large plastic bags. On pneumatic mills, or where filters are used, a damper or series of slide valves are usually located in the air discharge system. It is important to close dust collectors and filter vents to contain the fumigant within the machinery. Thermal currents and drafts can make a spot fumigation a total failure because vapors may be discharged to the atmosphere before reaching a killing concentration within the machinery. Windows in rooms housing equipment may be kept open during application to allow for adequate ventilation. A fan or hood area may also be employed to reduce the applicator's exposure to hydrogen phosphide gas. Approved respiratory protection must be available and is often required to be worn during application of the spot fumigant. Never fumigate alone. Using sharp scissors or a similar cutting device, cut the appropriate amount of fumigant from the roll of Prepacs and apply to the equipment. Be careful not to cut into the blisters and allow intact pellets or spent dust to fall into the machinery. Make sure the Prepacs are flat and are not folded over during application. Prominently mark or otherwise indicate the points of application so that the applied dose may be readily located and recovered after aeration. Immediately after application, close all doors and windows and turn off fans and ceiling ventilators to reduce drafts and air currents in the building during the exposure period. All accesses leading to the area under fumigation must be properly placarded with warning signs. Only authorized fumigators are permitted to enter treated areas prior to aeration. Aeration may be initiated, after the fumigation period, by turning on ventilation equipment and opening doors and windows in the treated areas. Remove covers from bins, vessels and other equipment and turn on dust collector fans. Aeration is generally complete in less than one hour. Do not remove warning placards or permit entry into treated areas, without respiratory protection, until the gas concentration is 0.3 ppm or below as indicated by a suitable detector for hydrogen phosphide. Collect all spent or partially spent Magtoxin from the treated equipment. Transport this material to an appropriate site for further deactivation and ultimate disposal following recommendations given in the Magtoxin Manual under "Disposal Instructions". Placarding of Fumigated Areas
The applicator must placard or post all
entrances to the structures and/or rooms containing equipment under fumigation with signs
bearing, in English and Spanish: The signal word DANGER/PELIGRO and the SKULL
AND CROSSBONES symbol in red. The statement "Area and/or commodity
under fumigation, DO NOT ENTER/NO ENTRE". The statement, "This sign may only be
removed after the commodity is completely aerated (contains 0.3 ppm or less of hydrogen
phosphide gas). If incompletely aerated commodity is transferred to a new site, the new
site must also be placarded if it contains more than 0.3 ppm. Workers must not be exposed
to more than 0.3 pprn hydrogen phosphide." The date and time fumigation begins and is
completed. Name of fumigant used. Name, address and telephone number of the
applicator. All entrances to a fumigated area must be placarded. Where possible, placards should be
placed in advance of the fumigation to keep unauthorized persons away. Do not remove
placards until the treated equipment and surrounding work areas are aerated down to 0.3
ppm hydrogen phosphide or less. To determine whether aeration is complete, each fumigated
area must be monitored and shown to contain 0.3 ppm or less hydrogen phosphide gas. If a
partially filled bin or tank has been treated, monitor the air space and, if feasible, in
the mass of the commodity prior to removing the placard. Transfer of an incompletely aerated commodity to a new site is permissible. However,
the new storage must be placarded if it contains more than 0.3 ppm hydrogen phosphide. No
placarding is required if aeration occurs during transfer. During the winter months it may be necessary for personnel to check the operation of
the boilers. The outside entrance to the boiler room must be used rather than entering
through a section of the plant under fumigation. Warning signs must be placed on the doors
which connect the boiler room to the plant. Workers who handle an incompletely aerated commodity must be informed and appropriate
measures taken (i.e., ventilation or respiratory protection) to prevent exposures from
exceeding 0.3 ppm hydrogen phosphide. Selection of a Fumigant
When selecting a fumigant, make sure that the label or labeling
states that the fumigant is permissible: For the commodity to be fumigated. For the pest to be controlled. In addition, one should consider several of
the following characteristics before making a decision: Toxicity to the target pest. Volatility and ability to penetrate. Corrosiveness, flammability and explosive
potential. The safety equipment that you have available. Warning properties and detection methods. The temperature at which it is to be used. Effect on seed germination or on finished
product quality. Residue tolerances, odors or tastes. Ease of application. Availability and cost. Aeration or Ventilation of
Fumigants
Aeration procedures vary according to the fumigant being used, the
type of installation being fumigated and the items being fumigated. Because of these
factors always read and follow the label instructions for the fumigant and situation for
which it is being used. Factors Affecting Aeration Time In addition to the characteristics, of the fumigant itself, the rate
of ventilation or aeration is affected by several factors. The more important of these are
the rate of air exchange and the temperature, which controls the amount of sorption and
the rate of desorption.
Rate of Air Exchange The rate of air exchange within the structure or area fumigated is the most important
factor affecting aeration. The exchange rate will be proportional to wind velocity through
the area, size and arrangement of area fumigated and mixing of the gases. When the
conditions for mixing the old gas with fresh air are good, the exchange of one volume of
air will reduce the fumigant concentration by one-half. The time for this reduction to
occur is referred to as "half lost time" (HLT). In atmospheric chambers an
exchange time of one air change per minute is desirable. In other areas, the most
effective practical method is to increase cross ventilation. Fans (non-sparking) are
useful for this purpose, as well as to stir up the air in "pockets" or
"dead spaces." Loaded areas aerate much slower than empty areas. Temperature Temperature affected the clearance rate of a fumigant because higher temperatures favor
the diffusion of the fumigant and the rate of desorption. In aeration of areas using cold
outside air in the colder months of the year the rate of diffusion and desorption is
slowed down requiring longer aeration time. For commodity fumigation it may be necessary
to close up the area and reheat it to 76 degrees F (24 degrees C) and then to repeat the
aeration process in order to satisfactorily remove the fumigant. This should not be
necessary for structural fumigations with methyl bromide. Sorption and Desorption The amount of fumigant sorbed by the materials in the area fumigated is referred to as
the "Load Factor." This-torbed fumigant is not available to act as a fumigant,
but must be removed in the aeration process. Some commodities are much more sorptive than
others just as some fumigants are much more subject to sorption than others. The greater
the -sorptive capacity of the fumigant and the item fumigated, the longer the desorption
process and the greater the aeration time needed. Generally, the lower the boiling point of the fumigant, the lower the amount of
sorption and the more rapid the aeration. Also, the greater the surface area of the items
being fumigated, the greater the sorption rate and the longer the aeration period needed
for desorption. Because of the slow desorption rate of grain, it is usually advisable to
hold it an additional 24 hours after the satisfactory aeration period. The exception is
phosphine which must be held for 48 hours. Particular attention must be given to retention
of fumigant gas by highly sorptive materials such as flour, meals, and jute bags. Procedures for aeration or ventilation will vary with the fumigant, and the area and items fumigated. Plans for aeration should be made before starting the fumigation. See the manufacturer booklets and labeling for specific recommendations on aerating their products. Building Ventilation
Additional References and AV Material
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