Trading Standards Institute Advice

Pest control in a food business: flies

This leaflet is for all food businesses including those involved in food preparation and production, retail premises, catering businesses, restaurants, pubs, cafes, and takeaway and fast-food shops.

The fly problem
When a fly lands on food, equipment or a work surface it causes contamination. Flies carry disease, spreading a range of bacteria including Salmonella, typhoid, cholera and parasitic worms. These are carried on their body hairs, the pads on their feet, their faeces and in the saliva that they give out when feeding. 

Even if a fly does not leave bacteria on food, it may still physically contaminate food (for example, it could fall into food).

It is far better to stop flies getting into your food area in the first place rather than trying to control them once they are in the food room.

Types of fly
Common house flies are most active in daylight and usually breed in decaying animal and vegetable waste. They are a problem in homes, food-production areas in factories, shops and rubbish tips.

Lesser house flies breed in rotting vegetation and manure. They can be a serious problem on farms. They are able to fly several miles so they could also be a problem if your business is near to a farm. They are not usually attracted by ultraviolet light, so electronic fly killers are not effective in controlling them.

Cluster flies hibernate in autumn. Large numbers of these flies may enter a building through the roof space to hibernate. Flies will often choose the same building year after year. They live outdoors during the summer, laying eggs in damp soil or rotting vegetation.

Blowflies breed in carcasses and scrap meat, and are found on rubbish tips, in food-production areas and in slaughter houses. The female may fly for many miles, before entering a food area to look for meat to feed on or a place to lay eggs.

Fruit flies are associated with poor kitchen or bar hygiene and breed very quickly in areas with rotting fruit  and vegetables, beer, fruit juices, vinegar, and milk that is going off.

Storing and preparing food
Keep food uncovered for as short a time as possible to reduce the chance of contamination by flies.

If you leave food on a work surface while you are preparing or cooling it, protect it from flies as much as possible (for example, by putting it in containers with lids or under washable net protectors).

Any pest control starts outside the building. Identify what might attract flies to your building and then put controls in place to so that they are no longer attracted.

Waste food, leftover tins and other packaging containing traces of food waste can attract flies and other pests. If possible, waste bins should be kept away from the building.

Food waste will need to be collected often, before you run out of storage space and the bins are overflowing. If it is not possible for your bins to be emptied as often as you need, make sure you have enough bins, with lids, to store the waste until it is collected. This includes food and materials that are for recycling.

For some businesses it may be worth investing in a waste compactor to help reduce the volume of waste, and so reduce the number of flies that may be attracted. 

Waste storage areas should be set up on a hard surface that is easy to clean.

Waste will be created from the food preparation stage through to the wash-up section in a cafe or restaurant. The food waste may include bottles, cans and packaging. You should have facilities in place to allow staff to work hygienically throughout the business, and make sure staff follow a 'clean as you go' routine. 

Use bin liners in bins in work areas, and make sure they are not overfilled so they don't spill while you are emptying them. After emptying the bins, clean them before putting in a new liner.

Remove waste from food-preparation and storage areas as often as possible. If it is not practical to always take the waste to the outside bins straightaway, store the waste in tied polythene bags. 

Don't leave waste inside overnight.

Flies will be less attracted to your business if you keep it clean and tidy. 

A well-designed and well-run cleaning schedule will make sure that walls, floors, doors, windows and ceilings are all cleaned regularly.

A cleaning schedule will also make sure that equipment is kept clean inside and out. You should move fridges, freezers, ovens and other equipment so you can clean underneath and behind them. 

A 'clean as you go' policy will make sure any spilt food waste or liquid is cleaned up immediately.

In storerooms, keep food in sealed containers and rotate stock regularly using date coding.

Clean outside drains regularly, particularly those near kitchen areas.

Fly screens
If you are leaving a window or door open for fresh air, you should fit screens to try to prevent flies from getting into the building.

Many companies make and fit fly screens. The screens can be a secondary door made of mesh, hanging plastic strips or metal chain curtains. Screens fitted to the inside of window frames are made from cleanable mesh fitted to a sliding frame which allows you to open and close the window.

Chemical control
You must not use fly sprays as they can cause chemical contamination if sprayed onto food or work surfaces where food is to be prepared.

Flypapers are unattractive and are not likely to impress your customers or be pleasant to work around.

Electronic flying insect killers
Most but not all flies are attracted by ultraviolet light.

Once flies have entered a building, they can be attracted by ultraviolet light into a fly trap. These electronic flying-insect killers, usually referred to as 'insectocutors' or 'fly zappers', electrocute the flies with an electric grid and the dead flies then fall into a catching tray below. You can then empty the catching tray.

Tips for using the traps:

  • you need to be careful where you put these traps in a food business - they should not be visible from outside as they may attract flies in
  • do not put electronic traps on a wall above a surface where you prepare food as a fly may fall from the catching tray into food being prepared below
  • the ultraviolet lights fitted to these traps should be replaced according to the manufacturer's instructions - although they may still seem bright to the human eye, you should still replace them after a few months as they lose their power to attract flies

Get advice from a pest control contractor. They may offer service contracts for flying-insect killers and be able to offer advice on other ways to prevent problems from insects. 

More information
You will find further guidance in our other leaflets on this website. Information can also be found on the Food Standards Agency website.

Alternatively, contact your local environmental health service for advice.

Please note
This leaflet is not an authoritative interpretation of the law and is intended only for guidance.

© 2018 itsa Ltd.