The protection of food against contamination from pests is a key prerequisite within a good manufacturing practice (GMP) system. Preventive methods include staff awareness training, adequate proofing, an effective pest control programme, minimising harbourage and potential food sources, and suitable control of incoming ingredients and materials that could support pest infestation. The major emphasis, however, must always be prevention.
22.1 The Prevention of Damage by Pests Act 1949 requires an occupier of any land or buildings to notify the local authority of rodent infestation. It also requires all local authorities to take steps to ensure that their district is free from rats or mice.
22.2 The Food Safety Act 1990 made it an offence to sell food that is unfit for human consumption or contains foreign bodies, for example pests, parts of pests or droppings. EU Regulation (EC) No. 852/2004 on the hygiene of foodstuffs requires that ‘The layout, design, construction, siting and size of food premises are to … permit good food hygiene practices, including protection against contamination and, in particular, pest control’. To do this requires measures including:
22.3 The principles of pest control are to limit food supply, access or movement of pests, and potential harbourage. There are two types of pest control: physical and chemical. Physical control methods are preferable as the pest is caught, cannot further contaminate the food and there is no risk of chemical contamination of food. Physical methods also include proofing of the building. Physical methods are not always completely effective, and a combined approach with chemicals may need to be used. A major concern with chemical control is that the pest may not be killed at the point of contact, for example ingestion, and could die later and possibly contaminate the food.
22.4 Incoming ingredients and materials should, as appropriate, be thoroughly inspected for signs of pest infestation as part of the quality control programme. All materials should be stored (see 22.10) to minimise the risk of infestation.
22.5 The most effective contribution towards infestation control is maintaining good housekeeping standards, for example controlling accumulations of food and paper debris, keeping gangways and passages clear, removing redundant equipment and materials from the manufacturing areas, and ensuring good stock rotation. External housekeeping is as important as internal housekeeping. External housekeeping includes:
22.6 All premises should either have personnel trained in pest control or employ a professional infestation control organisation for regular inspection, advice and treatment to deter and destroy infestation. An outside contractor should be accompanied on his/her visit by an appropriate staff member. It is important at the end of each visit to have a closing meeting with the contractor to discuss key points such as the current level of pest activity, contractor recommendations on proofing or general housekeeping, areas where the contractor has not been able to gain access to examine bait points and whether any actions recommended in previous visits have been addressed appropriately by the manufacturing organisation or if further action is required and if the documentation in the pest control file is up to date.
22.7 Site inspections should be regular and reports of each inspection should be kept on file to be available for future reference if required (see 22.16).
22.8 Care should be taken to ensure that bait spillages cannot pose a risk to any foodstuffs being manufactured or stored in the vicinity. Wherever practicable rodent baits should be based on fatty or waxy substrates. Risk assessment of individual locations should be undertaken to determine whether loose or solid bait materials will be used. The risk assessment should also assess whether only non‐toxic baits should be used in internal areas. Private standards differ in their prescriptions on this point and their requirements should be determined in order to ensure compliance and thus approval. Standards, such as the British Retail Consortium (BRC) Global Standard for Food Issue 7, prescribe that only non‐toxic baits can be used within production or storage areas where open product is present except when treating an active infestation (see 22.16).
22.9 No substances or application methods should be used in infestation control that have not been approved under the Control of Pesticides Regulations 1986 as amended 1997. Due attention should be given to risks of cross‐contamination, for example by spillage of grain bait, inadequate cleaning after chemical application to control pests and dispersal of tracking dust. Care should be taken to protect all materials, product, packaging, utensils and surfaces in contact with food from residual contamination by pest control substances.
22.10 Goods and equipment should always be stored at least 50 cm from adjacent walls to facilitate cleaning and inspection for rodents and insects. Drains and gutters should be fitted with screens and traps to prevent pest entry. Attention should also be paid to drains and drain pipes that could allow pest ingress.
22.11 Except where there are risks of dust explosions, all production areas should be supplied with electrical insect killing ‘knock‐down’ devices. These should be sited in areas of minimum light intensity for best effect, but should not be sited directly above any tanks, hoppers, conveyors, processing equipment, filling machines or open food.
22.12 Depending on insect type and the products being produced, pheromone traps may be used, where appropriate. Insect ‘knock‐down’ devices should be fitted with suitable catch trays that should regularly be inspected and emptied when necessary (see 22.16). These devices should be left switched on at all times even after production has finished and the premises vacated; this is particularly important during the summer months. The ultraviolet (UV) light tubes on these units should be shatterproof in design and replaced at least annually. The glass tubes should be suitably controlled under the site’s brittle material control procedures. The annual bulb change of the UV light should be recorded, plus any damage or breakage to the light bulb and the actions taken (see Chapter 19, 19.36–19.42).
22.13 Domestic animals, for example cats and dogs, should be excluded from manufacturing and storage areas. This is mainly accomplished by keeping all doorways and other entrances closed. Staff should never feed or otherwise encourage stray animals. Waste skips and waste storage areas should be adequately controlled to prevent attracting feral cats, especially on meat‐processing sites.
22.14 Birds and insects must be excluded from all production and storage areas. To do this effectively, all apertures in the roof or its eaves, or the walls should be identified and either closed off or suitably screened. Drains and guttering should also be fitted with screens and traps to prevent pest access. Doors and windows similarly should be suitably protected, for example by use of air curtains, strip curtains and netting (see 19.11).
22.15 Where there are already birds in the confines of the premises, they, and their nests, must be removed. In the UK there are legal requirements under the Wildlife and Countryside Act 1981, elsewhere due regard to the requirements of the various bird protection agencies must be observed.
22.16 The pest control programme should address the following steps:
22.17 The quality control manager and their nominated deputy must be responsible for the implementation of the pest control programme. They should be responsible for undertaking a review at regular intervals with the pest control contractor to ensure that the required level of service is maintained, for example the number of visits complies with the contract and that the programme provides effective control, there is a hazard data sheet in the file for each chemical control used and so forth.
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