Cockroaches are large brown insects ranging in size from 10 to 23mm in length. They have long, whip-like antennae and two pairs of wings. The most common species in the UK are the:

• Oriental cockroach
• German cockroach

These can be distinguished by their size and colour, with the Oriental cockroach being larger and darker in colour. Only the German cockroach can climb smooth vertical surfaces.

Nocturnal insects, cockroaches spend most of the day hiding in cracks and around drains and service ducting. Infestations may be introduced into premises in laundry and food deliveries.

Cockroaches carry food-poisoning germs on their bodies and are responsible for the spread of dysentery and gastroenteritis.

They feed on almost anything including food meant for human consumption and faecal matter..

Contamination occurs when the insect comes into contact with food or work surfaces or through faecal contamination of foodstuffs.

You can help prevent infestations by ensuring that:

• Premises and work areas are kept clean.
• Foods are properly stored and not left out in the open.
• Potential hiding places are kept clean such as junctions of walls and floors, vents, ducting and gaps behind or under equipment.

A cockroach infestation must be treated professionally. The pest control contractor will treat the premises with an insecticide spray. The treated area should be left undisturbed for as long as possible. It will be necessary to re-treat the premises to kill any new nymphs as they emerge from their eggs.