[Annual Rodent Control Issue] Giving Mice the Cold Shoulder

Rodent control in supermarkets and commercial kitchens is a challenge for even the most experienced pest management professional. That’s because these complex environments typically house scores of potential harborage sites for rodents.

Occasionally, mice (sometimes rats) will nest inside the insulated walls of food cooler and freezer boxes. If the infestations become severe, eliminating these rodents may be challenging. It is important to note, the client must be involved in the management strategy. The following procedures are recommended:

1. Limit all foods via sanitation or temporarily remove food from the cooler or freezer box and surrounding exterior. Foraging rodents that notice the food supply has suddenly disappeared will respond well to foods used to bait traps.
2. The same foods that the mice were eating prior to the cleanup should be used as the bait for the snap traps of multiple-catch traps (placing the bait in their entrances).
3. If multiple-catch curiosity traps are used, pieces of paper toweling can be placed partially into the entranceway of the traps. Mice in coolers often respond well to soft warm nesting materials. Mice will sometimes enter these holes when they encounter nesting materials.
4. If the entrances of the mice into the cooler/freezer walls can be found, these holes can be treated with a non-residual flushing agent as is done to inspect for the presence of insect pests. Often this causes infesting mice to evacuate the wall. The area surrounding the hole can be surrounded with rat-sized glue traps just prior to inspecting with the flushing agent. Any infested mice will become captured as they exit.
5. The same holes can be surrounded with double sets or mousetraps and left in place for mice as they exit from these holes to go foraging.
6. Once the mice in walls have been eliminated, the holes must be sealed closed using high-quality sealants.
7. If mechanical snap traps are used inside coolers and freezers, the traps should be exposed to the cold temperatures before being set. Otherwise, the traps will set on prematurely from the temperature change.
8. Tracking powders should never be applied into these walls (or anywhere else in a food-handling establishment) as the rodents can track the toxicant onto nearby stored and often exposed chilled or frozen foods or food storage surfaces.
    

This article was adapted from Rodent Control: A Practical Guide for Pest Management Professionals by Bobby Corrigan. To order the book, visit www.pctonline.com/store.