Researcher hails 'major milestone' for microwave sterilization technology

The Microwave Assisted Thermal Sterilization (MATS) technology is said to deliver higher nutrient retention values and allows for the drastic reduction of artificial ingredients or heavy loadings of extenders required to carry traditional products through conventional sterilization systems.

The process was developed over a 13-year period by Washington State University professor Juming Tang in collaboration with a host of food companies and the US army. It is targeted at pre-packaged, low-acid foods. The researcher said the technology also has huge potential to be developed as a pasteurisation tool for such items as frozen products.

Major milestone​

In the latest development to bringing the technology to market, US authorities gave approval in December 2010 for use of MATS in preserving so-called ‘non-homogeneous’​ foods – specifically salmon fillets in sauce. The FDA had previously green-lighted its use in 2009 for ‘homogeneous materials’​, in that case mashed potatoes.

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“The first approval validates the scientific and engineering premises behind our work,” ​Prof Tang said. “The second approval makes the technology viable for processing more complex food systems, which is a major milestone to commercialisation.”​

In late 2010, the university licensed the technology to private firm Food Chain Safety. The Washington state-based company has recently completed the designs for commercially viable microwave sterilization systems based on Prof Tang’s work.

In August 2010, Glenn Emory, vice president of strategy and development at FCS, told FoodProductionDaily.com that US military food supplier AmeriQual Foods was due to incorporate a MATS Series 150 unit into its production line by mid 2011.

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Technology ​

The technology immerses packaged food in pressurised hot water while simultaneously heating it with microwaves at a frequency of 915 MHz — a frequency which penetrates food more deeply than the 2450 MHz used in home microwave ovens. This combination eliminates food pathogens and spoilage microorganisms in just five to eight minutes and produces safe foods with much higher quality than conventionally processed ready-to-eat products, say the researchers.

Prof Tang said the breakthrough came through the development of a new chemical marker system to identify a food’s cold spot and ensure this was heated to somewhere between 250°F - 270°F. Other challenges the team overcame were providing microbial validation that the product has been sterilised.

Spearheaded by US Department of Defense’s combat feeding directorate, the project has received funding from numerous sources, including Kraft Foods, Hormel, Ocean Beauty Seafoods, Rexam Containers, and Graphic Packaging.