Store location is important. A detached store is less liable to infestation.

Store management, good hygiene and regular surveillance can help to prevent rodent harbourage. E.g. piles of unwanted building materials, damaged containers, packing cases, waste paper and floor sweepings should be removed completely and their accumulation prevented.

Apply rodent proofing techniques.

• Cover openings (ventilators, windows, sewage etc.) with gauge wire netting or expanded metal.
• Fix kick plates to the outer face of wooden doors
• Fix barriers on stack
• Paint with gloss paint any rough-walled building or barrier, to make surfaces too smooth for rodents to climb.
• Proof any horizontal pipes, wires and cables running between buildings or in the interior of the building.

RODENT CONTROL

The use of chemicals in a food store is toxic to all mammals - including humans - and food stocks could be contaminated.

It is generally prefered to have measures in-place, such as the ones described above, that will prevent the occurence of rodents.

If it is necessary to introduce rodent control measures in a food warehouse - e.g. traps, poison baits, fumigants, acute rodenticides or coagulants - contract the services of a reputable company able to provide the necessary safety assurances.

• Rodent traps

• Break-back traps with a treadle are the best type and should be laid across runs rather than along them. To control rats, they should be left unset for a few days until the rats are running freely over them. Traps for mice can be baited and set immediately.
• Live traps are less effective than break-back traps because most rodents are reluctant to enter the cage, and their use should be discouraged.
• Glue or sticky traps are another option that can be effective, particularly in relatively inaccessible areas.

• Acute rodenticides

Acute rodenticides (e.g. zinc phosphide) are effective after a single dose. The onset of poisoning symptoms is rapid and death may occur within less than one hour.

Acute rodenticides are among the most effective of the acute poisons but are hazardous and should only be used by experts.

• Chronic rodenticides/ Anticoagulants

Chronic rodenticides take much longer to act, and they can be taken repeatedly over a period of several days without the development of poison shyness. This type of rodenticide is safer to use. They are anticoagulants, a group of chemicals that prevent blood from clotting and eventually cause death from internal haemorrhage.
When using an anticoagulant bait:
• The bait should be placed in piles located where the rodents will find and eat them before reaching their normal food
• The amount of bait put in each pile should be about 100–200 g for rats and 25 g for mice. Eaten quantities should be replaced daily
• After about a week of using anticoagulants, the amount of bait eaten should rapidly decline as rodents begin to die
• All rodents should have died within 3 weeks for Norway rats, 4 weeks for roof rats, and 5 weeks for house mice.

• Fumigants

Rats and mice are more susceptible than insects to fumigants. Treatment with phosphine which isdesigned to control insect pests will also kill rats and mice.