This article features otherwise unpublished food safety management data held by BRCGS and Safefood 360° which, combined with real-time events, provides an unparalleled view of current and emerging issues and trends in the food safety industry.

 

Pests are defined as ‘a destructive insect or other animal that attacks crops, food, livestock, etc.’ The United States Food and Drug Administration (US FDA) defines pests in the Code of Federal Regulations as ‘any objectionable animals or insects including, but not limited to, birds, rodents, flies, and larvae.’ Pests can affect virtually anything that we interact with including animals and plants in farming and agriculture, food and non-food products.

Pests can contaminate products and adversely affect the quality and safety of a product. In most cases, infestation results in physical contamination or damage that is objectionable to the consumer, but in some cases the infestation leads to the product being unsafe to use or consume.

There is a wide range of pests that can affect products including rodents, insects and birds and, depending on the location, amphibians (frogs), reptiles (snakes) and any manner of local animal species. The core principles of preventing a pest infestation are relatively generic but the variety of threats can require local variations in approaches.

This article will only consider animal pests primarily affecting food, but it will have some relevance to the production environments for consumer products and packaging. I will focus on the management of common pests such as rodents, insects and birds.

 

The background

 

Pests come in a variety of shapes and sizes ranging from store product insects (SPIs) such as flour mites, to ants, fruit flies, house flies, cockroaches, mice, rats, birds, etc.

 

Common Name                                                                                         

Latin Name                                                                                 

  Ant (black ant)                                                               

Lasius niger                                                        

Flour mite                                                                 

Acarus siro                                                        

Cockroach (German cockroach)                                

Blattella germanica                                            

Fruit fly                                                                  

Drosophila melanogaster                                

House fly                                                          

Musca domestica                                           

     Blow fly                                                                     

Calliphora spp.                                                       

   House mouse                                                             

Mus musculus                                                     

Wood/Field mouse                                           

Apodemus sylvaticus                                      

Brown rat                                                           

Rattus norvegicus                                            

Pidgeon                                                           

Columba palumbus                                         

 

Many pests present a physical contamination risk to a product that is objectionable to the consumer. Insect larvae or bodies including ants, flies and cockroaches, hair or faeces from mice and rats, feathers or droppings from birds are just a few examples of undesirable findings in food or non-food products. Pests can cause physical damage to the item rendering it unfit for use or consumption, for example gnawing the packaging or the product.

Pests can also be the carriers of pathogenic micro-organisms. Birds are recognised carriers of Campylobacter spp. and their faeces on crops can result in localised contamination that is spread during further harvesting and processing. Rodents may be carriers pathogenic micro-organisms including both Salmonella spp. and Campylobacter spp.

A recent systematic review of the role of wildlife as spreaders of Campylobacter spp. has shown the potential risk from many that would be considered pests. Insects are recognised vectors of pathogenic micro-organisms, spread generally through human or animal faeces to raw materials and finished products. A recent study demonstrated a high prevalence of pathogenic micro-organisms including Shiga toxin-producing Escherichia coli STEC in flies captured in fields used for growing leafy greens near beef cattle where there is ready access to faeces.

Legislation throughout the world requires that products are made in premises protected from pest infestation and that such products are not exposed to contamination. Examples include EU Regulation No 852/2004 on the hygiene of foodstuffs and the US FDA Code of Federal Regulations Part 110 on Good Manufacturing Practice. CODEX extensively covers the measures that should be employed for the effective management of pests in the General Principles of Food Hygiene CXC-1-1969 (and subsequent amendments). Other examples of advice and good practice for pest control are available (Food Standards Agency, Food Standards Scotland and the British Pest Control Association).  

 

The control of pests

 

Exclusion: The first fundamental principle of effective pest control is to design and maintain the facility to prevent pest entry. Pests gain access to a production facility through gaps in floors, walls, ceilings/roofs or through services such as drainage or air handling systems. They can also enter through doors and windows that are left open.

Insects and small rodents can enter through very small holes or cracks whereas larger animals such as rats and birds need larger openings. The design and construction of a building must consider the potential risks of pests. To reduce risk, doors should fit close to the floor and be kept closed and windows should be covered with a mesh screen. Pest access points are often increased as factories age, due to natural wear and tear as well as alterations to buildings and equipment during the lifetime of a facility. Any alteration should be accompanied by a risk assessment to determine the potential increased risk of entry of all potential hazards including pests.

The general principles of hygienic design of production facilities that are applicable for microbiological, physical and chemical safety also provide for effective pest management. Industry and commercial guides are available for best practice in the design, construction and general proofing of building to prevent pest entry (European Hygienic Engineering and Design Group, Institute of Food Science and Technology, Codex General Principles of Food Hygiene).

A further consideration to prevent the entry of pests to the facility is managing incoming raw material and packaging, including equipment such as crates or pallets. It is essential that effective inspection routines are in place for the intake of all materials and that the controls are understood by suppliers so that pests are not transferred to the receiving site during deliveries.

Restriction: All pests need food, water, favourable temperatures and somewhere to live. Restricting access to these will reduce the overall potential for pest infestation.

Pests, on occasion, will breach even the best defences and it is important to plan for this eventuality. The key to preventing a breach becoming an infestation is the principle of denying shelter. Most pests seek areas that offer protection, and these are usually parts of the facility that are hidden from view. This not only offers protection but the opportunity to proliferate. Regular cleaning and maintenance is important. Store materials off the floor, put equipment where surrounding areas can be easily accessed and make repairs to walls, floors and ceilings that would otherwise provide voids for pests.

Food is one of the primary motivations for pests to enter and remain in a facility. Storing food off the floor works, but the key is to store food in such a way that it is not accessible to the pest. Packaged raw materials provide a degree of deterrence but many pests, especially rodents, can gnaw through thin packaging. Storing raw materials, work in progress and finished products in sealed containers and storage vessels provides the best defence against pest attack.

A source of food to many pests is often spillages and a clean as you go approach should be adopted in addition to end of production cleaning. This includes equipment, surfaces, floors and walls but also drains. Drainage systems can provide areas for pests to shelter and the presence of food combines to provide ideal conditions. This is why drains are often a key point for effective management of pests, especially in food factories.

Pests are attracted to waste, inside or outside a factory. Instigating processes for the regular removal of waste and cleaning of bins and surrounding areas is important in reducing the appeal. Use bins with tight-fitting lids, store them away from the production facility and deal with any spillages promptly.

Destruction (or control): The presence of pest activity or infestation may require the adoption of fast and effective eradication techniques. Integrated pest management (IPM) approaches using a combination of deterrence and, where necessary, destruction are accepted as best practice. however, spending an undue amount of effort on eradication without dealing with the root cause can be costly, time consuming and ultimately will never remove the pest completely.

Eradication can include the use of natural predators although this is only for use outside the production facility to deter potential invading species. A monitoring system should alert someone if a pest is identified. Toxic baits or trapping devices can cope with a few pests and can buy time for the pest controller to arrive.

Electric fly killers (EFKs) are commonplace in most factories for flying insects. It is important that they are citied away from open food handling, processing and packing areas and that they are regularly checked and emptied to monitor the presence of flies and remove dead ones.

Sticky boards have historically been used for insects and pheromone traps where the insect is attracted to the scent. Rodent traps, non-lethal or lethal have been used for many decades and where toxic bait is used in the latter, this must be done under advice from suitably qualified professionals and in line with regulatory requirements for the use of rodenticides. A variety of bait-free rodent control options are available that deliver both lethal and non-lethal control e.g. spring/snap traps and carbon dioxide. Pesticides may also be used for the control of insects especially where infestation is extensive, and the same precautions need to be employed when using insecticide in sprays and fogging.

Monitoring: A key element of any effective pest control programme is monitoring to identify activity and any trends in pest occurrence. Traps, pheromone detectors and electronic fly killers all act as indicators of pest activity and these should be checked regularly with activity recorded to monitor trends.

All monitoring devices should be marked on a site map and the inspection frequency defined in the pest management programme. It is important to recognise that monitoring activity does not identify the source of the infestation nor the root cause and any increases in pest activity should trigger further investigation and response that may require the support of third-party specialist advice.

More advanced pest control systems use digital and/or motion capture monitoring. Detection systems for rodents and insects can provide 24 hour continuous surveillance which has advantages over traditional approaches that rely on manual checks of monitoring devices. However, it is important to recognise that personnel play an important role in monitoring for pest infestation and signs of activity and are also key in delivering the key mitigations so training in pest awareness for all personnel is essential.

Professional pest management: Pest control is a skilled profession, and trained professionals should support the development of the pest control programme on a site. This may be undertaken by suitably qualified and trained site personnel but is most often undertaken by specialist third-party contractors from pest control businesses. In both cases, the pest control programme should be fully documented including the pest risk assessment, preventative measures, inspection routine and training provision.

 

Third-party certification schemes

 

Legislation is a key driver for management of pests but equally so is brand reputation and protection. Most reputable businesses implement measures beyond a legal minimum standard to protect their customers from exposure to harm and this equally applies to the management of pest infestation. Indeed, given the highly emotive nature of finding pests in a product, beyond any product safety risk, most businesses have highly advanced pest management programmes.

Third party assurance schemes such as BRCGS standards for Food Safety, Consumer Products and Packaging Materials all require the implementation and effective management of pest control programmes including measures to prevent entry, prevent proliferation, monitoring any activity and to review the adequacy of the programme. In addition, food safety software used for identification of hazards and management of risk such as Safefood 360° can also integrate the pest control and monitoring programme.

BRCGS also has comprehensive Best Practice Guideline for Pest Management that is an excellent reference source for the development of an effective pest management programme and Safefood 360° has an interesting blog on the considerations for effective pest control.

Pests are an inevitable part of producing products in our industry but with suitable risk assessment and preventive measures, it is possible to manage this risk to protect our collective customers.

 

Summary

 

I hope I have given you a bit of an insight about some common pests and a bit of food for thought regarding their control, something that can only be achieved through constant vigilance and attention to detail.

 

 

Author

 

Alec Kyriakides

Independent Food Safety Consultant