[Pest Control] The Global Challenge

Raw ingredients are just that — raw. Unprocessed, unrefined, often un-anything’d, a raw ingredient carries a high susceptibility to pest infestation. In fact, it is estimated that 10 percent of the global grain production is rendered inedible for humans by stored product pest contamination. When raw ingredients are delivered to a plant in bulk, from overseas or from an uninspected supplier, the potential for infestation and contamination increases dramatically.

The potential, however, can be decreased through preventive measures by the plant.

“It has to be a control process,” said Orkin Technical Manager Pat Copps. “The best thing is to prevent the infestation before it occurs.”

Preventing the infestation means understanding the pests to which your product is most susceptible, auditing suppliers for compliance, inspecting all inbound shipments to ensure you are not bringing pests into your plant, ensuring goods are correctly stored both before and after you receive them, and monitoring to prevent “overnight blossoming.”

THE PESTS. While there are scores of stored product pest species, the number that would be associated with any one commodity generally is quite limited. The first thing that a processor should do to protect itself against infestation is become familiar with the pests to which its products are most susceptible.

“What pests are normally associated with your specific commodity?” asked Earl Hallberg, technical services manager for Presto-X in Omaha, Neb. Once you know this, you want to learn and understand the biology, origin and habits of those pests. Then when a commodity comes in, inspect it for those pests.
Mark “Shep” Sheperdigian, vice president of technical services for Rose Pest Solutions, Troy, Mich., classifies pests into two categories: important pests and critical pests. “That’s all there are; there are no okay pests,” he said. “Everything you find is important. Some things may be critical."

“Most stored product pests can reproduce at a fairly quick rate and they can live in some fairly tough conditions,” said Myron Baumann, assistant vice president and regional manager for St. Paul, Minn.-based Ecolab Pest Elimination. In fact, a dusting of food along a beam within a plant is enough to keep a pest thriving, he said.

THE SUPPLIER. Prior to joining Ecolab, Baumann worked in the food processing industry and was, at one point, one of the people responsible for inspecting and sampling every shipment that came in for quality, texture and pests. As time went on, he said, this responsibility began shifting more and more toward the supplier. Although Baumann continued to do periodic checks on incoming goods, suppliers now had to comply with plant requirements to conduct the inspection themselves and provide a compliance report.

Problems that processors have with incoming raw ingredients often depend on how the commodity was handled and stored by the supplier. In many instances, these raw commodities have very low profit margins for the supplier, Hallberg said, “so they’re probably not going to do much with that product unless they absolutely have to.” As a result, he explained, “you’re inheriting the problems of that first storage.”

Whenever possible, a plant should conduct a full review of the storage practices of its suppliers. “Look at the facility or have a third party auditor look at the supplier,” Copps said.

THE INSPECTION. “The biggest thing about receiving anything into your plant, whether it’s food or packaging, is having some sort of inspection program at the dock,” Baumann said.

Incoming inspections should include visual checks of the product, the packaging, and transport conditions; testing of product samples, particularly for bulk commodities; and recording of all results in a logbook for ongoing reference.

Incoming bulk commodities can pose the greatest challenge to processors, Hallberg said, because it is difficult to inspect the areas where the pests are most likely to harbor. When you receive a 4-by-4-by-4 supersack of grain, he asked, “What is going on in the center of the burlap bag?” A similar issue occurs with tea shipped in wooden boxes. The boxes generally are not opened until the product is ready to be used, but there is no way to tell if there may be a problem until that box is opened.

Even when a package is opened, it can be difficult to tell if there is a problem with internal feeders, he added. “Your internal feeders — on beans, peas — could be anywhere in there. Unless you see adults on damaged kernels, you may not know there is a problem.” In addition, he said, because the pests are very small and don’t move around much, they can be very difficult to detect.

To get past these challenges, some processors will pull random samples to sift and view beneath a microscope. While this type of inspection works only with some products, “it doesn’t hurt to do it,” Hallberg said.

“Once you accept a product, it’s yours along with all the inherent problems that come with it,” he said. “Once you accept it, then it becomes your problem.”

Stored product pests can have long larval periods, and so can develop into an adult infestation seemingly overnight. So when susceptible incoming goods, such as raw and bulk ingredients, are put into storage, they should be placed where they can continue to be monitored. “Usually,” Copps said, “incoming goods are stored separately from finished products for that very reason.”

STORAGE. The conditions of the storage areas where a product is held — both before it is received at the plant and after — are critical to the condition of the product itself, particularly if it is held for any length of time. “Time and temperature are key. I can’t emphasize that enough,” Copps said. While it may not always be feasible, keeping warehouse temperatures no higher than 65° F is ideal for controlling stored product pests, he said. “That has a huge impact on the growth of stored product pests.” If you keep temperatures low, store for short time periods and keep the facility clean and dry, he said, “you won’t have a problem.” 

“Probably the most challenging thing is that most commodities that stored product pests would affect have a longer shelf life,” Baumann said. Baumann cites as an example the differences between a gallon of milk and a box of nonfat dried milk. The gallon of milk, which is generally drunk within a week or two of its processing, is not susceptible to stored product pests; nonfat dried milk, on the other hand, which can be kept on a shelf for years, is highly susceptible to such pests as the carpet beetle, Indian meal moth and warehouse beetle.

While the product itself can retain quality for a long period, its lengthy shelf life provides that much more opportunity for pests to infest and blossom, “often seeming to be out of control overnight,” Baumann said.  At less than a quarter-inch in length and preferring dark, quiet, out-of-the-way places, many stored product pests can sit virtually undetected in their larval stage, causing this overnight effect.

Pheromone traps can help a plant prevent this blossoming effect. Place them in susceptible areas to monitor for any incoming pests so a single pest can be prevented from becoming an infestation. Because a pheromone trap is specific to a limited number of stored product pests, the plant needs to be sure it is monitoring for those to which it is most susceptible. Light traps with glueboards also can be used for monitoring; though, as Copps warned, if you use light traps with trays, be sure to empty them regularly or the dead insects can attract dermestid beetles, and “you will be compounding your problem.”

Monitoring of pheromone traps also can provide record of a plant’s pest-free environment. If a customer does claim that your product had a pest problem, your records can show that there were no pests in your facility at the time the product was there. “Sometimes records don’t prove (the problem) didn’t come from the plant, but they can strongly suggest it,” Shepherdigian said. 

SECONDARY PESTS. Apart from contamination resulting from a stored product pest infestation, the very presence of certain pests can be an indicator of poor quality of goods. “A lot of stored product pests are associated with spoilage,” Baumann said, so their presence is an indicator of a quality issue. For example, he said there are certain pests that infest moldy or moist grain. The pest is, therefore, not the source of the problem but rather an indicator of a problem.

These secondary pests, such as the foreign grain beetle, the hairy fungus beetle and grain mites, are literally attracted by the damaged, moldy or moist commodity and should be a red flag that there is an overall issue with the quality of the incoming goods; an issue that will affect the quality of your outgoing product. “You don’t want to be using ingredients that are pretty nasty because it will affect the quality of your product,” Copps said.

The good news, according to Baumann, is that stored product pests are less of a challenge in today’s environment than in the past. “I think, as a whole, stored product pests are much less of an issue today than they were ten years ago.” He sees a number of reasons for this, including the fact that the industry has gotten much better at dealing with the pests.

One may think that the phaseout of methyl bromide would have increased the challenge, but its loss has actually made the processor more vigilant and aware of the need for prevention, sanitation and proper storage conditions all along the food supply chain, Baumann said. It is a vigilance which is well-placed and recompensed. Stored product pests are good flyers and good hitchhikers, he said. “All it takes is just the right spark somewhere in the chain.”

The author is staff editor of QA magazine and can be contacted at llupo@giemedia.com.