Segregation and rotation of stock ensure that pests do not find harbourage to breed

Segregation and rotation of stock ensure that pests do not find harbourage to breed

Protecting a warehouse

Uncontrolled pest infestations in a warehouse can result in adverse publicity, product recall and prosecution, warns Mohammad Arif Hussain, entomologist, Masa Establishment

01 October 2016

The consequences for freight companies associated with pest activity can be serious and costly. Pest species can transfer disease and bacteria, they can lower the quality of raw material through damage or physical contamination, and can cause damage to property by gnawing or burrowing – requiring expensive remedial works. Should such uncontrolled pest infestations occur, the results can be adverse publicity, product recall, prosecution and loss of revenue. 

Many pest problems are caused by poor hygiene, in which good housekeeping standards will help prevent the spread and harbourage of insects and rodents. Any equipment or containers used for freight should be well maintained and regularly cleaned to help prevent pests being attracted to commodities. 

Good housekeeping and the segregation and rotation of stock also ensures that pests do not find harbourage amongst items that are long standing, removing the chance for pests to establish colonies.

Warehouses and holding depots are potential hives of pest activity as the accumulation of goods and foodstuffs from multiple sources will undoubtedly introduce some form of pest species. The result of cross-contamination by pests in such a location can be the transferral of insects or rodents to multiple end users, such as factories, shops or members of the public. It is essential that warehouses and holding depots have a means of inspecting and proactively monitoring for the activity of pests.

Though much attention is often paid to the freight, the transport vehicle is also susceptible to infestation and needs equal attention, for example mice and cockroaches have been found within aircraft on the ground. Therefore, it follows that any area in which a vehicle is parked in between trips should have a pest prevention programme in place to minimise the risk of infestation and reduce possible down time to a business.

The main pest species to look out for are rodents and insects. Insects, in particular, stored product insects such as biscuit beetle and rust-red flour beetle can be imported with food commodities, and wood-boring insects can be found in wooden furniture.



Pest controllers will need to work closely with their customers in the freight and other industries to eradicate and prevent pest activity. Measures such as good hygiene, regular inspection, careful attention to building design and better training will all contribute to establishing integrated pest management (IPM). This is a pest control strategy that combines physical, chemical and biological methods to achieve comprehensive control and pest eradication. IPM is a long term solution that allows the customer and the pest controller to work together and gain control without the continual use of poisons, which can only be positive for the environment. IPM is the future of pest control and will require positive input from all those involved in pest management. 



The common housefly is a known carrier of diseases and pathogens, including Listeria and even Salmonella. Houseflies reproduce rapidly; the current school of thought is that one pair of houseflies would have over 500,000 descendants over a six-year period, though not all would survive. Another common food plant insect is the fruit fly, which reproduces just as quickly.

A Masa technician at a work site

A Masa technician at a work site

Flying insect control requires removal of breeding sites, such as the roof puddles and food sources.

Garbage is a prime source for both food and breeding sites; therefore, dumpsters must be placed away from open doors. All standing water should be eliminated from processing and distribution properties.

Keeping flying insects from entering buildings is difficult but essential. Screen doors work on standard doors, but not as well on dock doors. There are alternatives, such as air curtains and strip doors for dock doors. Air curtains are effective but must be monitored to be certain the airflow points outward. Strip doors are also effective if installed and maintained correctly.

Indoor flying insect control can be achieved with electrocuters, sticky traps or baited flytraps but must be maintained correctly and cleaned periodically. Bulbs must be changed regularly, as most lose their effectiveness after six months. 

Insecticide fogging is another alternative but must be performed only by a licensed technician from a reputable pest management firm that is knowledgeable about pest management in food plants.

Another food plant pest is the cockroach, which is known to transmit diseases and bacteria. It is best to know which species we are fighting to know its breeding areas. We can determine the species by placing insect traps around the facility; be certain to map the traps so we can check and collect them all. We can then identify which species we have trapped and battle them accordingly. Be complete with your placement; set traps in electrical junction boxes, behind and beneath equipment, control panels and even floor drains if it can be done safely. Insect evidence is a critical finding in any food manufacturing or distribution facilities.



As carriers of various bacterial and viral pathogens, rats and mice pose a serious hazard for the logistics and warehousing industry. The list of signs of an infestation is long but includes evidence of gnawing, smudges of excrement, feeding damage to merchandise, packaging materials and cables, as well as shredded nesting material.

Masa recommends identifying structural weaknesses and closing off access points such as joints, cracks or holes in walls, ceilings and doors. Strategically placed bait around the site exterior will also help prevent an influx of rodents and infestation of stored products in the future. Monitoring solutions should be implemented to ensure the early detection of any infestation in known problem areas such as cold storage or the food and non-food sector. In this way, specific control measures will only be needed for acute infestations.



Food and textile stored in warehouses are a tempting source of food for many uninvited guests. These include food and textile moths, cheese, flour, storage and cocoa mites, fur, rice grain, corn and biscuit beetles. Contamination of stored goods with their feces, tissue, shed skin and feeding damage can cause enormous financial loss.

In addition, an infestation often creates heat and humidity, the perfect breeding grounds for dangerous mold spores. It is vital to act quickly at the first signs of an infestation to prevent it from spreading rapidly.



Crawling insects that pose a threat include the German or Oriental cockroach, ants, crickets, beetles, spiders, woodlice, earwigs and dust mites who find warehouses a welcoming environment for breeding. Depending on the material being stored – food (raw materials), textiles, animal feed, tobacco and so on – other pests could also be present.



Bird pests, especially sparrows and pigeons, leave no stone unturned in their search for food and can penetrate the interior of warehouses and storage rooms, contaminating raw materials and merchandise.

Constantly opening and closing roller shutters in loading docks and materials handling areas, as well as nearby waste containers, make these areas highly attractive to birds.

Birds transmit bacterial infections such as Salmonella and Psittacosis, viruses such as Newcastle disease and parasites such as ticks, mites or bugs that can contaminate stock. It is therefore vital to prevent birds from penetrating buildings by deploying appropriate deterrent.

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