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New technology improves food safety and flavor

A new technology that is now available to food companies can increase the consumer appeal of chilled or frozen meals sold in retail markets while reducing the chance of contamination. 
Juming Tang, distinguished chair of Food Engineering and associate chair of Biological Systems Engineering. 

A group of engineers led by Dr. Juming Tang, distinguished chair of Food Engineering and associate chair of Biological Systems Engineering at Washington State University, has developed a novel microwave-assisted pasteurization system that can semi-continuously process 8- to 20-ounce pre-packaged chilled meals. This marks an important milestone in a research program funded by a $5 million USDA National Institute of Food and Agriculture grant awarded in 2011 to WSU and partners across the country.

As the developer of the technology, WSU leads the collaborative work conducted for the NIFA grant. WSU has established “pilot-scale capacity” whereby Tang and his colleagues can work with food companies to adapt the technology to a producer’s needs and then manufacture production equipment via a third party, making the system “scalable for industrial production,” said Tang. WSU anticipates licensing this technology to its start-up, Food Chain Safety for commercialization in the coming months.

According to Tang, the 915 MHz microwave-assisted pasteurization process significantly improves upon traditional thermal pasteurization, offering food producers a more efficient means of making foods safe and a more effective means of preserving food quality. After two to four minutes of heating the product to 194 F, which is 55 F below the temperature typically used in commercial sterilization, the numbers of pathogenic bacteria can be reduced a million-fold.

“We can control foodborne pathogens and viruses and provide high-quality products,” said Tang. The MAPS process also allows traditionally frozen meals to be refrigerated instead of frozen, saving retailers and consumers significant energy costs.

“We had some exciting early results. The quality of microwave pasteurized foods—specifically mollusks, shrimp and tofu—is substantially better than conventionally pasteurized foods,” said Dr. Barbara Rasco, professor in WSU’s School of Food Science and a collaborator on this project. A shelf life exceeding one month at refrigeration temperatures has been achieved for several formulated food itmes, including stroganoffs, curries, burritos, and hors d'oeuvres. 

Working to keep frozen and child foods safe, Tang and colleagues use a pilot-scale microwave-assisted pasteurization system developed at WSU.
The technology developed by Tang’s laboratory may help fulfill the mandate of the 2011 Food Safety Modernization Act, which requires food producers nationwide to add steps in food production operations to make sure that products are safe, Tang said.

“This new technology is an excellent example of the type of innovation NIFA seeks to deploy across the nation to keep our food supply safe for all consumers,” said Sonny Ramaswamy, NIFA director. “Food safety is a critical priority for USDA, and I applaud Washington State University’s efforts to address this challenge with ground-breaking research that will be useful for food processors testing the safety and quality of their products.”

Other institutions involved with the USDA project include the University of Tennessee, North Carolina State University, the U.S. Army Soldier Systems Center, and USDA-ARS Eastern Regional Research Center. Further information on the people and organizations involved can be found at

-Sabrina Zearott

Can good fungi restore bad soil?

Tarah Sullivan is fascinated by fungi, especially the ones in agricultural soils that offer hope for addressing toxicity issues by transforming harmful metals.  
As a new assistant professor of soil microbiology in the WSU Department of Crop and Soil Sciences, Sullivan is busy setting up her laboratory to study how soil microbescan transform toxic metals like aluminum, cadmium, and lead into less toxic forms, and how they can help plants take up essential micronutrients like iron, zinc and copper.

Tarah Sullivan and Geoff Gadd. Photo by Shelly Hanks, WSU.

“One idea that gets people excited is the possibility that beneficial fungi could help address the increasing soil acidification and aluminum toxicity problems found in the Palouse,” Sullivan said.

In the last 50 years, soil acidity has increased due to the use of nitrogen fertilizers. The bad news is that soil acidity can cause dramatic decreases in yields, in many locations up to 50 percent or more for sensitive crops, such as garbanzos, lentils, wheat, and barley, according to Sullivan. Soil acidity transforms naturally-occurring aluminum into a soluble form that is more available to plants and which damages their roots. A common though costly solution to aluminum toxicity is to reduce soil acidity by applying lime to soil. But the effects are often short lived.

The good news is that fungi are plentiful and tolerant of acidic soils, and many are even well-suited for remediation of metals. According to Sullivan, as soils become more acidic, fungi can comprise more than 75 percent of soil microbes by mass -- and most are the good guys.

“There are hundreds of billions of microbes in one gram of soil. An extremely small proportion of them are pathogens. The vast majority of soil microbes are beneficial and we don't fully understand those,” Sullivan said.

Many species of fungi associated with plant roots, called mycorrhizal fungi, have been shown to decrease aluminum toxicity in plants. Sullivan wants to know how we can enhance these beneficial soil fungal populations in the field and how we can promote their metal-detoxifying activities.

Fungi on the surface of lead shot transform lead minerals into a less toxic form. Photo by Geoff Gadd. 

She hopes to identify specific fungi that have the aluminum buffering qualities, and then see if it’s possible to inoculate the soil with them to extend the benefits of liming. She also hopes to discover whether it’s possible to create soil conditions that favor the beneficial fungi by adding soil amendments, such as compost or straw.

Ultimately, Sullivan believes her research will contribute to a sustainable approach to mitigating soil acidification problems in the Palouse, providing a more environmentally friendly and economically viable long-term strategy.

Sullivan holds a doctorate in soil microbiology from Cornell University and comes to WSU following postdoctoral research at Oak Ridge National Laboratory where she focused on soil fungal communities in a lead-contaminated military site. She recently hosted a Department of Crop and Soil Sciences seminar presented by Geoffrey Michael Gadd, an internationally known geomycologist from the University of Dundee in Scotland who studies how fungi transform the chemical composition of rocks and minerals.

Learn more about mycology and crop and soil sciences at

-Sylvia Kantor


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