A Strategic Approach to Stored Product Pest Infestations
Stored product pest insects are a common concern in the Food Processing Industry within all facilities that incorporate and/or produce a dried ingredient or product. These insects in general are of little consequence with respect to food safety as they typically are not associated with pathogenic bacteria transmission. However when it comes to ensuring product integrity, customer satisfaction and protecting brand image their presence must not be ignored. Stored product pest insects have high reproductive rates (majority produce hundreds of eggs in a their short lifetime), great mobility and dispersal capabilities, and use pheromones for communication, allowing them to take advantage of their environment and thrive. These same qualities make exposed food products and ingredients extremely vulnerable to infestation and contamination.
Some of the most prevalent stored product pest insects include Red and Confused flour beetles, Saw-toothed and Merchant grain beetles, Warehouse beetles, and Indian meal and Mediterranean flour moths. Each insect species has its own food preferences but in general they will infest items such as flour, spices, nuts, dried fruit, chocolate, cocoa powder, powdered milk, dried pet foods, and cereal. Knowing the specific biology and food preferences of these common species is an important first step in preventing infestations from developing. This knowledge is also critical when trying to eliminate known infestation within the facility.
There are multiple factors that need to be considered and strategies that need to be implemented to manage and minimize the potential impact of stored product pest insects. Working in conjunction with a quality pest control provider the following key actions must be performed:
Identify the ingredients within your production process that are vulnerable to infestation. Your incoming goods and warehouse inspections, inventory practices, and cleaning activities with respect to these items must be enhanced to reduce their risk to your end product. Equipment processing these ingredients must have detailed cleaning procedures with the frequency of cleaning set to disrupt the life cycle of any associated stored product pests.
Identify potential sources of insect infestation both within and outside the facility through conducting detailed facility inspections. Shipments from suppliers are a potential source of infestation that can often be identified through a detailed incoming goods inspection. Within the facility, sources of infestation can include inadequately cleaned equipment either in use within production or in storage, old dried ingredients or food items stored within warehouses, inadequately cleaned surfaces such as overhead pipes, and accumulations within void spaces such as concrete block walls, ceilings, etc.
Depending on the stored product pest involved, pheromone traps can be implemented within the facility to help identify hot spots for infestation. Pheromone traps for Warehouse beetles, Indian meal moths, and Mediterranean flour moths are highly effective in attracting these insects. Evenly spacing the pheromone traps at 40 foot intervals on a grid system layout will provide unbiased data capture that can be spatially analyzed to identify infestation hot zones within the facility. Trending the data in this manner not only helps to focus and improve existing cleaning practices but also allows for the identification of chronic problem areas within the facility over time.
Infested incoming goods should be rejected prior to unloading into the facility. The supplier should be contacted to discuss the integrity of their product(s) and where assurance cannot be given or fulfilled as to future shipments a new supplier should be investigated.
Infested food items in storage (ingredients or final product) should be evaluated as to their suitability for use. Where value is minimal these items should be disposed. Where the Food Processor wishes to keep the infested items for use, fumigation may be performed to kill all life stages of the pest. In conjunction to these measures, the storage area must be thoroughly cleaned to remove all life stages that have emerged from the product. A crack and crevice and possible ultra low volume (ULV) (fogging) insecticide treatment to the storage area should supplement the cleaning action to ensure control.
Infested equipment, silos, or an area within / complete facility should be evaluated to determine the level of infestation and the appropriate action. In many instances infested equipment and structures can be heat treated or fumigated for insect control. Depending on the severity however it may be possible to gain control through intensifying cleaning and performing crack and crevice and / or ULV insecticide treatments in the area of infestation.
Ultimately it may be impossible for some Food Processors to completely eliminate the presence of stored product pests within their facilities. The implementation of these control strategies greatly minimizes the potential for product adulteration through insect infestation, providing a quality food product to the consumer.
Steven Graff is the Quality Assurance Manager at Abell Pest Control. Holding a Biological Science Honours degree from the University of Guelph, he has written and developed many nationally recognized papers, articles and training programs in the field of Pest Control, Integrated Pest Management and related fields. In his 15th year with Abell, he directs a team of Auditors and Field Trainers, who support hundreds of Technical staff for Abell and their Customers.