The Dirty Truth About Sanitation and Stored Product Pests

“The gods had condemned Sisyphus to ceaselessly rolling a stone to the top of a mountain, whence the stone would fall back of its own weight,” wrote Albert Camus in “The Myth of Sisyphus.” “They had thought with some reason that there is no more dreadful punishment than futile and hopeless labor.”

You have likely heard it before, sanitation is essential when it comes to pest management. All living things need food, water and shelter. Pests are attracted to the abundance of food and shelter that a food processing or storage facility provides — it’s an unlimited buffet for them. Sanitation is cleaning up and removing the food source so there’s nothing for them to eat. And if there is nothing for them to eat, they aren’t attracted to enter and infest.

So sanitation is easy, right? Just clean up all the food at your site.

Of course, that is impossible: How could you possibly clean up all the food when you are making and storing that food? Since most facilities are in operation 24 hours a day, seven days a week, there is never going to be a time there is not food there. Between raw ingredients, in-process material and finished products, the food is there. Sanitation is a hopeless, impossible, dare we say Sisyphean task.

Or is it? These case studies are an example of how much sanitation plays a role in stored product pest control, whether you’re rolling a stone or not.

You can’t always get what you want ...

No matter how much effort a facility puts into a sanitation program, there is always going to be a food source. Accept the fact that you won’t get perfect sanitation. The goal is to get as much as possible and then limit the access to what is still present. By finding the major sanitation issues, those can start to be addressed. It can help to prioritize the sanitation problems, especially if there are many of them to deal with. Focusing on the top five or 10 biggest issues can provide the biggest results.

I once visited a chocolate factory that was having some pretty significant issues with Indian meal moths. This was an older site with older processing equipment. There was lots of spilled product throughout the production area and quite a bit of food waste at the end of the production cycle into the packaging area. It wasn’t possible to clean up every bit of waste that was coming off the production lines, but the site started prioritizing some of the worst areas and cleaning those every shift (instead of weekly). By consistently removing that particular spillage, and taking the trash bins out regularly, the moth problem was significantly reduced. There were still sanitation issues, not all of the spillage could be removed at all times, but much more of it was being removed to limit what the moths had available to eat. As a bonus, it physically removed many of the larvae that were feasting on the waste products.

But you should try ...

I was visiting a feed mill that had no real sanitation program. There was spilled raw ingredients and finished food product everywhere. In most areas, I couldn’t even see the floor because it was covered in feed material.

“I’m not going to bother cleaning, it will just get dirty tomorrow,” the manager told me.

I asked him if he had stopped bathing because he was just going to get dirty the next day. He didn’t find that funny. I didn’t find it funny that there were more mice than people and the insect issues were out of control.

Ignoring the problem will not make it go away. Sometimes, creative solutions can help to minimize the access to food for pests. While we typically talk about keeping insects out of a facility (seal off the inside from the outside), also consider sealing the inside from, well, the rest of the inside. There was a flour mill I worked with and, as you can imagine, cleaning up all the flour dust was impossible. There was a sanitation program in place, but the flour beetle numbers weren’t going down. We found the majority of the issue was on just one floor. By sealing off all the openings that led to the other floors, we could contain the issue to the one area and not let it spread. Sanitation efforts were refocused to the floor that was having the most issues and the beetle population stabilized.

You just may find ...

Monitoring can help you find where sanitation issues are and get to them before they become widespread throughout a site. Using the monitoring data can focus inspection efforts and sanitation efforts to where they will have the most impact on pest issues. Sometimes sanitation issues are hidden and aren’t obvious until it is too late, and insects have already found the food source and infested it. Monitors can be an early warning system to pest issues stemming from sanitation problems.

A warehouse beetle issue had been progressing through a large food manufacturing facility I visited. This was mostly dry processing, but they did not have a pheromone monitoring program in place, so by the time they noticed the warehouse beetles, they were fairly widespread through the facility. On first inspection, there did not seem to be significant sanitation issues. After installing a monitoring program, the highest number of beetles was found in the raw ingredients warehouse and was narrowed down to one area. Turns out, a tote of dry milk powder had been pushed back into a corner and other pallets had been stacked in front of it. It had broken open and no one had noticed for months. This gave the beetles plenty of time to reproduce and spread. Using the monitors allowed us to focus in on a problem area, find the sanitation issue, remove it and eliminate the warehouse beetles.

You get what you need ...

Sanitation makes pest control more effective. Many studies have looked at what limiting food intake does to pest populations. In almost every case, when insects are starved or have insufficient food, they expend more energy looking for food and competing with other individuals for that food. That means they are growing slower, they aren’t mating as much or producing as many offspring and their mortality rates are higher.

Sanitation also affects treatments. Better sanitation means pests are more actively out of their harborages and looking for food, so they are contacted by treatments more. Because they are stressed out from lack of food, they can be more susceptible to the treatments as well.

One processing site I worked with was having an issue with flour beetles. They were fogging the entire mill every month at a pretty significant cost. The counts in their monitoring devices reduced slightly but were back up a week after the treatment. Because there was a significant layer of food debris, the majority of the flour beetles were protected underneath that layer of debris and the fogging never contacted them. Cleaning up the spillage before a fogging significantly increased the treatment efficacy, and the number of beetles after the fogging was lower and stayed lower than previous treatments.

It’s not just about what your site gets. Your customers get what they need too: clean, pest-free products.

Sanitation is just one step in an integrated pest control program, but it is an important one. Every piece of food that can be removed or contained to make it harder for pests to get to is beneficial.

Every sanitation item that can be done is another steppingstone to get better results from your pest management program. While sanitation may seem hopeless and an endless task, you have to keep it rolling.

The author is a consulting entomologist at 360 Pest & Food Safety Consulting.