Safe storage of food in warehouses has always been a challenge as there are about more than 30 different insects, several rodents, birds and other animals which may be attracted to stored food areas, causing losses and contamination problems in warehouses.
There are multiple key components necessary for successful Integrated Pest Management programmes in any warehouse:
The first step in managing stored product pests is effective sanitation programmes which include sanitation measures outside and inside the warehouse. Exterior areas of the warehouse must be kept neat and clean so that this will not attract insects or rodents. Clutter like unused pallets, used packaging material, used gunny bags should be removed. A vegetation free zone or barrier around the outside perimeter of warehouse will discourage crawling insects and rodents. All cleaning duties are divided into two types namely Daily and Periodical (weekly or longer).
There should be a master cleaning schedule for sanitation. Proper waste disposal mechanism is necessary to avoid stored pest problems.
Building design and Pest proofing
Pest proofing means preventing pests from entering the warehouse. It provides the best long term solution and reduces the need for repeated chemical control.
Exterior area: Many pest problems originate outside the food plant and can be effectively managed by eliminating conditions around the structure which allows the pest to find harborage. Exterior pest proofing techniques involves:
• Entrance and Exit doors – automatic door closing mechanism must be used. Metal doors instead of wood are preferred as wood is susceptible to weathering and gnawing by rodents. Screen doors should be fitted. Air curtains or plastic stripes should be installed to prevent entry or movement of flying incoming pests.
• Windows – should be properly designed and fitted with a mesh.
• Foundation – all openings greater than ¼ inch should be sealed to prevent rodents.
• Drains and Vents – These provide convenient entry points for insects as well as rodents and hence must be adequately screened and cleaned.
• Utility lines – Plumbing pipes, electrical conduits etc, all serve as convenient runways for pest entry into the building as gaps are created wherever they enter the structure. These gaps must be sealed.
• Roofs – All openings in the roof must be tight fitting and properly sealed to prevent any entry of pests.
• Shipping and receiving docks – All exterior docks should be constructed with an overhang, this acts as a barrier against rodents.
Interior area: Proper building design and interior pest-proofing of a food warehouse discourages proliferation of any pests that have already gained access in to the building. Ceiling, wall and floor should be free of cracks.
• Inspection aisles next to wall should be painted white and products are to be stored away from walls.
• Proper management of storage pallets used inside food warehouses is important as they harbor various pests.
• Infested packaging materials act as breeding grounds for insects. Proper cleaning, quarantine and pest management procedures must be implemented to prevent infestation.
• Always implement and follow Good Warehousing Practices (GWP) like FIFO principle etc.
Insect Traps and Monitoring – locating the source of infestation and identifying the insects are important. Sensitive monitoring tools for various pests, like species specific Pheromone traps are used to determine the location and intensity of insect infestations.
Pesticides application – Pesticides application within warehouses may involve fumigation, space treatment and the application of residual sprays. When considering using pesticides in the food warehouse, the approved list of pesticides given by Central Insecticide Board must be selected. Refer pesticide labels for detail information regarding the correct use of pesticides. Broadly pesticides applications are classified as residual and non-residual insecticides. General pesticide spray applications are always in non-food areas. Spot applications are limited to areas where insect pests have been observed. Fogging or Ultra Low Volume misting are carried out in spaces. Pesticide application should always be done by licensed and trained PCOs by using appropriate personnel protective equipment. Pesticides should not contaminate foods stored in the warehouse.
Fumigation – All fumigants are gases and quickly disperse to reach the target organism. Fumigants used are broad spectrum insecticide and kill all living creatures in enclosed area. No protective residues are left behind (if used properly), unlike liquid and solid pesticides. There are only two fumigants registered in India, namely methyl bromide and phosphine. Both are classified as restricted pesticides due to extremely toxic nature. Methyl bromide is an ozone depleting gas, its use is legally restricted only for quarantine and pre-shipment fumigation purposes in India and governed by Directorate of Plant Protection, Quarantine and Storage which authorizes and issues licenses to fumigators.
It is very important for exporters/warehouse owners to select a pest management company carefully. They must ensure that company has all the valid govt. licenses and approvals. The company must also have experience, well qualified and trained personnel and the knowledge of Indian fumigation standards, quarantine procedures also the guidelines & procedures laid down by the European, Australian, American plant protection and quarantine authorities to carry out these extremely dangerous services. Taking shortcuts is not advisable as it will prove counter-productive and lead to huge losses for exporters.
Business Development Manager
Pest Control (India) Pvt Ltd
The author is Board Certified Entomologist (BCE) by Entomological Society of America, Food Plant Pest anagement–Purdue University, USA, and Food afety for Warehousing and Distribution –AIB, USA