You may have heard of the joke that goes something like this: “What’s worse than biting into an apple and finding a worm? Finding only half a worm!” While pests in our food have been the subject of jokes, pests in the food manufacturing environment are no laughing matter.
The food plant environment is extremely attractive to pests as it provides ideal conditions and basic survival needs: food, water, warmth/temperature, security and absence of natural predators. Insects and rodents are attracted to both odors from food plants and the lighting used inside and outside the facility. Pest control is a requirement for conformance to federal regulations. The Code of Federal Regulations, Current Good Manufacturing Practices (21 C.F.R. 110.35), makes it very clear that pests are to be excluded from food plants and is described as follows:
(c) Pest control. No pests shall be allowed in any area of a food plant. Effective measures shall be taken to exclude pests from the processing areas and to protect against the contamination of food on the premises by pests. The use of insecticides or rodenticides is permitted only under precautions and restrictions that will protect against the contamination of food, food-contact surfaces, and food-packaging materials.
Pest infestation results in product adulteration, which can lead to product loss, possible recall or regulatory control action and potential loss of business. In addition, many pests carry disease or spread microbes, damage ingredients and infest finished products. For example, mosquitoes carry diseases such as West Nile virus, flies and roaches spread microbes due to the environment in which they feed or breed, beetles can infest breading or flour, rendering it unusable, rodents can transmit hantavirus and birds can carry Salmonella. As such, plants will often include pest control as a prerequisite program for their Hazard Analysis and Critical Control Points plan to demonstrate that contamination of ingredients and foods is not reasonably likely to occur.
However, it is not enough to have pest control as a prerequisite program. The program must be supported by senior corporate/plant management, fully implemented and involve several steps to ensure that the food manufacturing facility, ingredients or finished products are not adulterated. The approach most recommended for control of pests is integrated pest management (IPM). IPM is a multiple-hurdle approach that provides several barriers to thwart pests. It begins with the recognition that pests have three basic survival needs—food, water and shelter. It uses approaches to control conditions that will allow pests to survive. These approaches include elimination of breeding and harborage areas both inside and outside the plant, exclusion from access to the plant, sanitation and extermination.
The focus of this article will be on the implementation of sanitation for the control of conditions outside and inside the plant to prevent the attraction of pests.
Sanitation
Poor outdoor sanitation or internal housekeeping can lead to harborage, attraction and breeding of pests that can eventually make their way into the manufacturing facility. Once inside the facility, they will gravitate to where ingredients or finished goods are stored and contaminate these materials and the facility itself. Regular cleaning will prevent the harborage, attraction, breeding or infestation of pests.
External
Maintain the grounds of the facility in a clean condition. Make sure that plant grounds are well drained to prevent stagnant water or pooling water sources on grounds or on flat roofs that can become harborage areas. For mosquito control, eliminate standing, stagnant water, stock fishponds with mosquito-eating species and use mosquito bacterial agents that won’t affect environment or aquatic life. This includes the removal of conditions that can result in standing water such as low spots in parking or facility grounds.
An area that can often be overlooked is the roof, where ducts vent from the plant to the outside. Vents that are connected to mixers, such as vacuum blenders, can often pull food material from the mixers and deposit it on the plant roof. Vents from areas where there may be significant food dust may also deposit this material on the roof. This material attracts pests that may eventually enter the plant through these vents or other openings. In addition to cleaning the roof, it is important to clean the vent itself, but there must be hose stations on the roof or at roof access points if the vent is to be cleaned from the top down.
Other areas that may be overlooked include load levelers at dock doors. These are typically open from the outside; materials, including food, can become trapped inside, creating an attraction for pests. These levelers must be cleaned regularly—daily is ideal but no less than weekly. These typically will require only a dry cleaning, but they should be evaluated to determine if wet cleaning is necessary.
Stray trash from plant processes or neighboring facilities must be removed regularly to prevent attraction and harborage. Trash compactors and refuse containers close to the building must be maintained in sanitary conditions. While all attempts must be made to avoid spills, as these containers are filled with plant waste, occasional spills are unavoidable. All spilled product must be removed immediately, and the areas under and around the compactors/containers are to be hosed and scrubbed once each processing or operating day. Depending on the soils found around these containers, it might not be sufficient to simply hose them; it may become necessary to use cleaning chemicals to remove the soil. If this is necessary, then the sanitation group needs to know local and state regulations governing the chemical runoff that will travel to sewage or local drainage. It is recommended that all paved areas on the property be hosed every week if they potentially present an attractant to pests.
If the plant has external areas for employees to take breaks or enjoy their lunches, it is important to provide a sufficient number of self-closing trash containers for the number of employees who will use these areas. Employees must be trained to throw their trash into these containers and not leave it on tables or on the ground, as this will attract pests. In addition, the sanitation/janitorial personnel must have this area on their routine route for cleaning and emptying the trash cans. Routine cleaning should be a dry pickup and trash removal, but if the area does become soiled, then wet cleaning should be included to remove food soils.
In animal slaughter operations, it is necessary to clean holding pens and chutes or live hang areas to remove all animal waste. Offal areas that open to the outside will require regular cleaning to eliminate scraps that will attract pests. Daily removal of trash and offal will prevent attraction or harborage of pests. Clean up spills around storage tanks on a regular basis. Materials, such as corn, soy or flour, are attractive food sources for pests. Dry spills may require only
a dry sweeping and pickup, whereas oils or syrups will likely require a wet cleaning.
Internal
Sanitation inside all buildings is important to eliminate sources of food to prevent pest attraction and feeding. The frequency of facility and equipment cleaning varies by type of production and regulatory requirements. A complete cleaning of the manufacturing environment will eliminate accumulated food soils that can provide attraction and nutrition for pests. Personnel conducting pre-op sanitation inspections must be trained to ensure that the plant has been cleaned to the level expected. In addition, they should be trained to look for indications that sanitation has not been effective and has resulted in the presence of and harborage of pests.
One example of an indication of inadequate sanitation is the presence of drain flies or common nuisance flies, fruit flies, phorid flies and moth flies. Organic buildup in drains, sewage filters, p-traps and disposals creates breeding grounds their larvae thrive in. Because they survive in the organic material in the drain, the drain must be scrubbed clean to remove the buildup of material. Simply pouring chemicals down the drain will not eliminate the flies or the harborage environment for the flies. In addition to effective sanitation, there are environmentally friendly materials that break up organic material in drains, eliminating the food source and helping promote effective drainage.
As part of their routines, sanitation/janitorial personnel will have to empty internal trash containers, both inside and outside production areas, no less than once every 24 hours or more often to ensure that trash does not overflow the containers. These containers must also be cleaned regularly and should be included on the master sanitation schedule. These containers do not need to be covered if they are emptied and scrubbed once every 24 hours. All spilled product and food items within all buildings should be cleaned and removed as quickly as possible.
It is also important to implement sanitary design concepts for the equipment and the facility to prevent areas where food can become trapped. This means that equipment should be designed to facilitate cleaning and eliminate areas where food can accumulate and where pests can enter and possibly breed. Facility design should include coating over floor slabs to eliminate cracks that can harbor food or pests. Overhead beams should be avoided in the facility design or have angled surfaces as opposed to flat ones so that they do not accumulate soils and can be easily cleaned.
Employee Good Manufacturing Practices should reflect that food will not be allowed to be stored or consumed in locker rooms and lockers will be inspected regularly. The lockers should also be emptied for cleaning by sanitation on a regular basis. This cleaning should be included in the master sanitation schedule. The employees must also be instructed not to leave food scrap or waste, including open drink cans, on tables inside the break room of the plant. Waste must be thrown away, and break rooms must be cleaned regularly during production days.
Warehouse areas must be kept clean, especially around load levelers as noted earlier. All nonrefrigerated storage areas should have a rodent control strip. Maintain 18-inch perimeters around storage racks or floor storage for cleaning and observation. It is highly recommended that this perimeter be painted white to provide a visual aid for storage and for contrast if there are soils or spilled ingredients present. It is very important to address product spills immediately in storage areas to prevent accumulation and pest attraction.
The role of sanitation and janitorial personnel in pest control cannot be overlooked, and their training is very vital. They must be trained specifically to understand how their actions can be critical to effective pest control. Some of the specific training points are as follows:
• They must be trained not to block open doors to the outside when they are cleaning or removing trash. While this may make their jobs somewhat easier, it facilitates the access of pests into the facility.
• They must be trained to ensure that pest control devices, such as internal rodent traps, are positioned properly at the completion of sanitation. Often these devices are moved to facilitate the sanitation process or to prevent them from getting wet. Once they are replaced, they must be properly positioned so that the opening is close to the wall, making it easier to get the rodent into the trap.
• They must be trained to be aware of the presence of pests and know whom to notify if there are pests present and what actions to take to restore sanitary conditions.
• Unless they are trained and licensed applicators, they must be instructed that they cannot apply pest control chemicals that are not acceptable for use in a food facility.
Extermination
Despite your best efforts to exclude pests, there will likely be times when they still enter the plant. Pests are opportunistic and can enter the facility through extremely small openings. Key sizes to remember for openings are that an opening ½ inch square or round and smaller is rat- and large-bird-proof; an opening ¼ inch square or round and smaller is mouse- and small-bird-proof; and screening for windows and doors 22 mesh and finer is fly- and insect-proof. Even with air curtains that operate over doors, there is a possibility that pest insects can enter the plant if the velocity is not sufficient or if it does not control pests that travel on the ground.
In the event that pests do enter the plant, there are methods that can be used to exterminate them. These include trapping and chemical application. If traps, such as insect traps (including electrocution devices) or rodent traps, are used, they must be maintained in sanitary conditions. If birds enter the plant, they must be trapped for removal. It is not recommended that you use a firearm to eliminate birds as this presents a significant danger to plant personnel or may damage the plant structure. A means of trapping the birds must be developed, followed by inspection and sanitation of any areas that may be soiled by bird droppings.
Chemical Interventions/Insecticides
One of the benefits of IPM is employment of methods that reduce the need for chemical application. As much as possible, chemical use should be a last resort or a minor supplement to the comprehensive plant program. However, if chemicals must be used, then facility personnel responsible for pest control must be familiar with federal regulations such as the Federal Insecticide, Fungicide and Rodenticide Act, which regulates the registration, use and disposal of insecticides. It is also important to determine what insecticide is appropriate for the pest being controlled and for the area to which the insecticide is being applied.
Some insecticides contain harmful chemicals that leave a longer-lasting residual, whereas others become inert on contact or within a brief amount of time. Residual chemicals kill both immediately and over time. Because they continue to act, they must only be used outside of the food facility in areas where plant employees will not be traveling so they do not track pesticides into the manufacturing facility. Other chemicals, such as pyrethrum, work only on contact, do not leave a residual kill and do not kill over time.
Because residual insecticides are effective for several days, they are best used for crack and crevice treatment that will be followed by sealing of the treated crack and cleaning of the entire treated area. Though residuals are not recommended for fogging, they may be applied to larger areas such as floors at wall junctions where insects are tracking or outside the plant to treat walls or floors in dumpster areas where flies might congregate or rest. With any residual application, all regulations for use must be followed for safety reasons.
Nonresidual insecticides are most often used for fogging or space spraying to knock down adults. Nonresidual sprays may be used in production or personnel welfare areas provided there are no ingredients, food products or employee uniforms present. If nonresiduals are used in food contact areas, food should be removed and contact surfaces covered before and cleaned after use. If fogging with nonresiduals, follow with a full cleanup and sanitizing procedure of all work areas, lockers and equipment.
Conclusions
Preventing pests from entering the plant and infesting ingredients, product or the facility requires the application of multiple strategies starting with a written pest control program and including habitat elimination, exclusion, sanitation and eradication. If all elements are incorporated, the plant and company can avoid product contamination that may lead to expensive losses of product or business. Effective sanitation can greatly minimize the conditions that attract or result in the harborage of pests.
The technical expertise and documentation required for effective programs can be supplied by a number of qualified and certified pest control companies. Drawing from a variety of control measures, specialized programs can address immediate concerns, long-term prevention strategies and third-party inspection standards. This ensures the quality, value and safety of food products, as well as company employees and the environment.
Michael Cramer is the senior director, food safety and quality assurance, for Windsor Foods. He serves on the Editorial Advisory Board for Food Safety Magazine.
