Insect control articles and pest control news

10 May 2018

Controlling flies in commercial food sites

Pest control | PPC91 May 2018

As professional pest controllers, many of us deal with large and small food sites and it is essential that we focus on which pests pose the most significant risk to our customers. Although rodent infestations tend to be considered a more extreme issue by customers, flying insects that can pose the greatest risk to the contamination of products and packaging.

Chris Cagienard from Pest Solutions, Glasgow makes a case for how and why we prioritise flying insect control in food sites.

 The fly in the ointment

Speed read

Due to their size and mobility, flies can move far more freely, and bypass our exclusion measures with much greater ease, than any rodent. Unlike rodents and many other pests, fly species are often tolerated at background levels within food production, handling, packaging and retail areas.

There can often be a limited concern when there are seasonally-acceptable fly count numbers recorded within the catch trays of the electric fly killer (EFK) units that we service. It is true that it is almost impossible to exclude all flies and that our catch tray results demonstrate if our control measures are being effective. However, the fact that we have these species of flies present means that there is a real and present contamination risk to any exposed product.

Back to basics understanding of biology

Contamination of products with flying insect parts remains a significant issue for many food and packaging companies.

In addition to the physical contamination by flies or insect parts, we are also aware that flies are one of the most prolific propagators of disease due to their feeding practices and the likelihood that they have alighted on unclean surfaces before landing on products or packaging.

A product recall due to insect contamination (and the potential for loss of clients) is often a real fear for our customers in the food industry.

Let’s make sure we are always taking fly control seriously for our clients and working towards achieving better results and outcomes at all times.

Remember flying insect biology

Often new clients who have had long-term fly issues have told me a previous contractor had merely prescribed the purchase of more EFKs. This is clearly not always the right solution for the end-user.

It is fundamental that the first thing we do with any fly issue is to go back to basics and understand the biology of the flying insect we are dealing with.

In many cases, understanding the biology and behaviour of the flies we have issues with can lead us to identify and remove a breeding site, a food source or other encouraging factors.

If we give the right advice, our customers will build a more robust long-term relationship with us. This way you’re far less likely to lose a valuable contract to the guy that sells cheaper EFKs or fly screens.

Fly screens and door policy

Our second focus should be the exclusion of flies from any vulnerable areas. The simplest way of excluding most pests is good door policy. Keeping doors closed when not in use. This can often be bolstered with some of the following systems:

  • Fly screens and doors
  • Chain curtains
  • Strip curtains
  • Air curtains
  • Other proofing.

These can often be excellent product solutions that we can add to our services to increase sales. If the installation of these seems daunting, many industry suppliers can deliver these services for you under your company name.

Fly control units – EFKs

Fly control units EFK

Fly control units can be and are a mainstay of any integrated pest management plan and are a prerequisite for delivering a service on any food site. The technology and quality of modern EFKs have come a long way, and we have a more comprehensive range of products to choose from than ever.

However, no matter how much we advise our clients that they require a certain type of unit there will always be the client that goes and buys those cheap catering supply units. I’m sure they do a job in some situations but they are not fit-for-purpose in every commercial site. Often the catch trays can be too small to retain flies and they are not able to be adequately cleaned or serviced. I would highly recommend refusing to service these units and I would recommend a replacement unit.

We have such a wide range of types of fly control units at our disposal including:

  • Electric grid units
  • Glue board units
  • Intrinsically safe units
  • Low energy units
  • External use units
  • Discrete units.

When setting out our fly control strategy and selecting the right EFKs for the job it is important to position them adequately. Are we sure our units are not positioned above any production lines or product preparation areas that could be contaminated by fly parts from the unit? Have we made sure to position the units in a location that will not attract flies in from outside? Have we considered ease and safety of access for servicing?

Monitor or control method

As part of our pest risk assessment we should consider whether we are using EFKs as a control method or as a monitoring method.
In all food sites we should always work towards EFKs being a monitoring method first and a control method as a failsafe.
If we become reliant on EFKs as a primary control method inside a food production we are allowing an unacceptable risk of product contamination.

Reporting and servicing of EFKs

On our food sites we should ensure that we use the information that the EFKs can provide to full effect. Fly counts in relation to the position of each unit can give us a wealth of information about issues or potential issues within our sites. For example the presence of rogers ants and elevated numbers of drain flies in a catch tray may suggest a specific problem within the drains in that location.

Make sure that trends are documented and communicate this information to customers so that the progress and resolution of an infestation can be tracked. Referring to historical trends can act as a helpful early warning that a more significant issue is looming.

To ensure that EFKs within any food site where we deliver our services are fully operational we must ensure they are serviced and maintained correctly.

There are EFK-related courses available for technicians to attend and there is excellent online EFK servicing learning material in the CPD zone of the BPCA website.

Eye spy with my little fly

There are over 100,000 species of flies in the world. Would you be able to identify these flies if you found them on your rounds?

Cluster fly

Cluster fly
(Pollenia rudis)

Common house fly

Common house fly
(Musca domestica)

Lesser house fly

Lesser house fly
(Fannia canicularis)

Stable fly

Stable fly
(Stomoxys calcitrans)


(Calliphora vicina)

Fruit fly

Fruit fly
(Drosophila spp.)

Horse fly

Horse fly

Common house mosquito

Common house mosquito
(Culex pipiens pipiens)

Biting midge

Biting midge

Sewage fly

Sewage fly
(Psychoda spp.)



Flying insect control will always be a significant part of an integrated pest management plan delivered to the food industry.

Within the BPCA membership we all take great pride in doing our best for clients and working to increase the professionalism of our industry.

Let’s make sure we offer and provide effective solutions and work towards the best outcomes for our customers when it comes to flying insect control.

Three top tips on effective fly control for food sites

1. Remember your biology

When we work alongside our customers and reassure them that we understand the consequences of issues like product contamination we are speaking their language. Any advice given will be taken more seriously, and is more likely to get your client to understand the importance of your recommendations.

2. Product contamination risks are important 

This is always the first place we should go. As professional pest controllers we have the chance to impress our customers with the depth of our knowledge and training. Applying simple basic principles and delivering simple but effective results will always strengthen the relationship with the customer.

3. EFKs can be an excellent product sale

When we have established that additional EFKs are the solution these are an excellent product upsell. We are spoilt for choice with some excellent well-engineered units that we can sell on to our clients with the associated servicing. There are even some low energy EFKs available that can save your clients more than the cost of the unit in two to three years, making the conversation about upgrading older units a justifiable investment. This can help towards many customers ISO14001 goals and carbon footprint reduction targets.


Check out BPCA’s training programmes:

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Chris CagienardChris Cagienard
Pest Solutions Glasgow

1 May 2018  |  PPC91

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