Adam’s Pest Control Solves Who, What and Where of Mouse Droppings

Adam’s Pest Control, a Food Protection Alliance member, received a request to investigate a shipment that was returned from California to the producer in Minnesota due to mouse droppings on the final product. The documentation of the PMP at Adam’s Pest Control was able to show exactly where the droppings occurred and who was responsible.

Situation.
This case started when mouse droppings were found inside a box of a client’s products which were shipped to California. The whole shipment was rejected and sent back to its origin in the Minnesota Twin Cities. Our client asked us to investigate the issue and come up with justifications and recommendations.

Solution.
To solve the issue, we had to follow a number of steps.

The first step was to identify the droppings. This step was crucial to ensure that they were indeed mouse droppings and not droppings that belonged to other animals, such as shrews, American cockroaches, squirrels, etc.

Through careful inspection, we confirmed that the evidence were mouse droppings and moved onto the next step of determining the place of infestation. Did the droppings originate in Minnesota or were they introduced in California after the shipment had arrived? In order to answer this, we looked at where and how the boxes were stored. If the inside of the boxes were stored face up, droppings on top of the box could be folded up and sealed inside. It would be unlikely to have droppings stuck on the bottom of a stack of boxes.

The most important factor that helped us solve this issue was our record keeping and documentation practices. We looked at the process by which the product was made, processed and handled. This was compared to the history of mice activity in the plant at each level.

The products were made and immediately placed into a freezer, rotated through until frozen where they were placed on layers of wax paper inside the box, which was folded and taped. Boxes were taped shut and placed on a pallet. When the pallet was full, a forklift drove the boxes into a freezer that was kept at 10°F. This temperature is too cold for mice infestation. Additionally, we have had zero history of mice in the freezer. If a mouse were packaged inside the box, it would die in there or have a lot Adam’s Pest Control Solves Who, What and Where of Mouse Droppings more droppings in there, as a mouse excretes about 50 droppings per day, which is about one every 30 minutes. From our understanding, the customer found one dropping and shipped the box back to our client’s plant where two more droppings were found. This might indicate that a single dropping didn’t just fall into the box, and that a mouse didn’t excrete the droppings during the one minute of packaging.

Another step to investigate was during transportation. When the boxes go from the freezer to a semi-trailer, they usually sit on the trailer in the ‘Freezer Section.’ History tells us that trailers can sometimes be the source of infestation. We asked to inspect the trailer that was used for the transportation of the products. We also inspected the box for any markings to determine if the box was chewed and if a hole of at least 3/8” in diameter was created so that a mouse could get inside during transit.

We also collected information about the end location storage situation. Their process was to store received products in a refrigerator, which mice are more likely to visit, infest, or even survive than in a freezer. We also wondered if the product was unwrapped and used, with the leftovers immediately put back in a freezer or refrigerator. Was the partially used case sealed up or how was it stored? Droppings could occur while a case was in the kitchen, or when it was stored in the cooler.

Since the above information did not provide us with a conclusive evidence of potential mice infestations, we recommended that our clients perform an on-site inspection at the end location to see if they had a significant mouse issue. Since mice signs can be somewhat removed, we recommended our client to inspect in the false ceilings (mice are excellent climbers and can climb down for food and return to the ceiling). This final inspection proved to be the case solver: mouse droppings were indeed found in the false ceiling, and our client won the case.

Conclusion.
We were able to save our client’s business through our documented record system that displayed all pest control activities and corrective actions taken in our service location, along with educating our client on how to inspect for mice activity at the end location. As a critical component in integrated pest management, the documentation of each performed activity must be accurate, up-to-date, and include inspection for evidence of pests in each plant area.

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FPA is an organization of regional companies formally organized to provide Pest Management/Food Safety/ Fumigation/Alternatives and Fumigation & Product sales throughout North America. 1-877-FPA(372)-3334.