August 1, 2015 | Robert Nieminen

The third quarter 2015 Milling Journal features an article on how Temp-Air, Inc. helps milling facilities control pests safely.

Problem: A troubling bug infestation has just been discovered inside your milling facility that threatens to damage the quality of the food product. Solution: You might go the traditional route and temporarily close down operations, so the facility can be fumigated. However, an extended shutdown means lost productivity and revenue. There are also the inherent dangers associated with using pesticides that can be not only harmful to the environment but also to human health.

Or you could consider thermal remediation, a high-temperature treatment performed in a scientific manner to eradicate stored-product pests safely and effectively without any structural damage to the facility or storage structure.

Controlling Pests Safely

Given the consumer trend relying less on chemicals, treating insect in-festations with heat has been making a strong comeback. No one knows this better than Temp-Air, Inc., Burnsville, MN (800-836-7432), a leading provider of temporary, portable heating, cooling, dehumidifying, and air filtration rental services in the United States.

Founded in 1965, the company ap-plied its expertise and received a patent in 1999 for its Thermal Remediation® process for controlling stored-product pests in food processing facilities.

While the process of treating insects with heat isn’t new, it’s been refined and used as an effective strategy to manage insects due to global environmental and regulatory concerns, increased insect resistance to certain chemicals and stronger demand for safer control methods.

As a result, food processing plants, flour mills, rice mills, cereal and pasta processing plants, warehouse/packaging facilities, bakeries, and many other industries use thermal remediation equipment for controlling stored product pests.

“Temp-Air is celebrating its 50th year of being in business,” says Raj Hulasare, senior scientist and product manager, Thermal Remediation, a division of Temp-Air. “The Thermal Remediation division began in about 1999 and was basically an offshoot of Temp-Air’s construction heating and cooling business. Based on that experience, we collaborated with Kansas State University (KSU), Manhattan, in 1999 to understand exactly how the insects behave at high temperatures.

The company’s collaboration with KSU in 1999 investigated the effect of high temperatures on stored-product pests. The research showed that tem-peratures greater than 122 degrees F effectively kill all life stages of insects (eggs, larvae, pupae, and adults), unlike chemical fumigation, where a higher concentration may be required to kill the eggs or immature life stages.

This resulting research helped Temp-Air develop its patented heating process, which offers the company a competitive advantage.

According to Hulasare, there are two basic ways to manage insect infestation using heat.

One way is to put a heater inside the room and shut the door, so that the air recirculates until the designated temperature (122 degrees F) is reached and then held for 12 to 36 hours to attain a lethal threshold.

Another method, which Temp-Air specializes in, is to pressurize the space by placing a heater outside the facility that raises the temperature of the air and then forces it into the room.

“This is referred to as the positive pressurization principle, wherein any pressurized room is being heat-treated,” he says.

The proprietary process employs a combination of direct-fired (natural gas, propane, or steam-fueled) makeup heaters, fans, and ductwork to control the flow of air and maintain uniform temperature profiles throughout the treatment area. The positive pressure throughout the treated space pushes hot air into corners, cracks, and crevices making it virtually impossible for pests to hide anywhere.

Temp-Air’s clients include mills and plants with very large facilities that measure in the millions of cubic feet, spread across North American, Europe, and Asia, according to Hulasare.

“Our company has been in the heating and cooling construction business for the past 50 years, so we have very good experience in terms of how to heat a structure and in engineering dynamics,” he explains.

Relying on Research

Does heat really work as well as chemicals in terms of pest management? It’s a valid question, and any skepticism is understandable, especially given that comprehensive scientific data on the effects of high temperatures on various stored product pests and their life stages (eggs to adult) was not available for many years.

However, thanks in large part to Temp-Air and its partners, a wealth of scientific information is now available on the efficacy of heat to kill stored product pests.

For example, with funding from the Propane Education and Research Council (PERC), Temp-Air collaborated with Purdue University from 2007 to 2009 to demonstrate the effectiveness of heat to control stored-product pests in bins and silos and found that most insects die in less than a few hours at 122 degrees F. All life stages are killed when exposed for more than five hours.

More recently in 2010, Temp-Air again collaborated with PERC and KSU on a project titled, “Demonstration of Heat Treatment as a Viable Methyl Bromide Alternative for Disinfesting Grain-Processing Facilities.” This was supported with a grant from the Environmental Protection Agency (EPA) to further demonstrate the effectiveness and benefits of thermal remediation over fumigation under the MBT (methyl bromide transition) grant.

Under the MBT grant, Temp-Air, with the support from PERC, sponsored the 6th Heat Treatment Workshop, where the company successfully heat-treated the state-of-the-art Hal Ross Flour Mill at KSU and proved that thermal remediation is equally as effective as fumigation without any of the drawbacks (see “Controlling Red Flour Beetle,” Milling Journal, Fourth Quarter 2010).

Advantages of Heat

Fumigation is basically using a highly toxic chemical gas, like methyl bromide, which now has been banned because of the Montreal Protocol,” says Hulasare. “The reason it is being banned, is because it has been proven to deplete the ozone layer, and that’s one of the fundamental reasons why people are moving toward non-chemical alternatives.”

Additionally, Hulasare says that the EPA has established buffer zone guidelines that mills must maintain while fumigating. As a result, occupants and others are prevented from coming within specific distance of a facility being chemically fumigated, which is not required during thermal remediation.

“That’s one of the advantages of heat treatment,” Hulasare. “You can be heat-treating the mill while at the same time, shipping in the warehouse, or office work still can be running, because you’re just heat-treating fresh air – you’re not using any chemicals. One can enter the facility during the heat treatment to observe areas [cracks and crevices] from insects emerge during heat treatment that enables the facility to perform cracks and crevices treatment after heat treatment. The downtime [production shutdown] also is reduced significantly by heat treating compared to chemical fumigation.

Hulasare also notes that heat treatment of stored-product is completely non-toxic and is non-corrosive, unlike ethyl-phosphine, another widely-used fumigant that has a corrosive effect on electrical conduits and motors.

According to Hulasare, other advantages of thermal remediation include:

  • No phaseout, unlike banned chemicals.
  • Only heat treatment allows inspection during the treatment to detect areas of insect emergence and take corrective action like cracks/crevices treatment.
  • Less downtime.
  • No associated costs of insurance and contacting local authorities.
  • The whole structure or part of the facility (spot treatment) can be heat-treated.
  • Heat treatment can be performed in warm- and cold-weather conditions.
  • Heat does not have any long-term, damaging side effects.
  • Heat treatment may reduce the frequency of plant shutdowns with proper integrated pest management (IPM) practices.

For all its benefits, however, thermal remediation is not a cure-all for pest control. As Hulasare explains, nothing can substitute for proper sanitation and thorough IPM practices.

“Thermal remediation is not a 100% solution,” he says. “It is part of the multiple strategies that a mill employs and it is very much a part of an IPM program and sanitation is a major and critical factor. More than 50% of the pest problems can be resolved, if you have very good sanitation.”