Cockroaches in the workplace: signs, risks and prevention

Cockroaches are one of the most persistent pests a business can have. Restaurants, cafés, hotels, offices, warehouses and care settings can all be affected, anywhere with warmth, moisture and food. Because they hide during the day, an infestation is often well established before anyone sees one.

01The two species you are likely to meet

• German cockroach. Small, light brown, and the main problem in commercial kitchens. It likes warmth and humidity: behind cookers, dishwashers and fridge motors, and inside equipment. It breeds quickly.
• Oriental cockroach. Larger, dark brown to black, and slower. It tolerates cooler conditions and is often found at ground level, around drains, in basements, cellars and service ducts.

Telling them apart matters, because they live in different places and the treatment is targeted accordingly. A large brown beetle at a window in spring is more likely to be a cockchafer, and our guide to telling a cockroach from a cockchafer shows the difference.

02Why commercial premises suit them

Kitchens, staff break rooms, bin stores and plant rooms provide food, water and warm shelter. Pipework, drainage and ducting connect one space to the next, so cockroaches move between rooms, and in shared buildings between businesses. They also arrive in deliveries, packaging and second-hand equipment.

03The risks to your business

• Hygiene. Cockroaches pick up bacteria such as salmonella and E. coli from drains and waste and carry them onto food and surfaces.
• Health. Their droppings, shed skins and dead bodies build up in dust and can trigger allergies and asthma.
• Compliance. In a food business, cockroach activity is a serious finding at inspection and can lead to enforcement action.
• Reputation. A cockroach seen by a customer, guest or member of staff is remembered, and often shared.

Where vulnerable people are present, such as in care homes, healthcare and childcare settings, the stakes are higher still.

04Signs of an infestation

• live cockroaches, especially at night or when lights are switched on
• dead cockroaches in corners, under equipment or in light fittings
• small dark droppings like ground pepper, or dark smears along edges
• egg cases (oothecae) in warm cracks near appliances
• an oily, musty smell in enclosed areas

A cockroach seen in daylight often means numbers are high enough that the hiding places are full.

05Why sprays rarely work

Shop-bought sprays kill the cockroaches they hit, but the colony is hidden in voids and equipment, and egg cases protect the next generation. Spraying can also scatter cockroaches into new areas. Professional treatment uses gel baits and residual treatment placed at the harbourage, followed by monitoring and repeat visits until the site is clear.

06Prevention

• clean behind and under equipment regularly, not just the surfaces in use
• fix leaks and dripping taps, and keep drains clean and covered
• seal cracks, gaps around pipes and gaps behind wall-mounted equipment
• store food in sealed containers and keep waste areas clean
• check deliveries and second-hand equipment before they come inside

Even well-run premises can be affected, particularly in shared buildings. Regular inspection catches activity early, when it is far easier to deal with.