Tuesday, September 4, 2012


Rapid development of microwave heating process during the last 25 years has enabled food processing industry and the house hold kitchens to prepare foods rapidly without the conventional electric or gas based heating systems. There is no doubt that microwave ovens have become a ubiquitous part of almost all kitchens in most developed countries because of the great convenience factor associated with their use. Ever since Raytheon developed its monstrous 1.8 meter tall, 340 kg, 3 kWh energy guzzling Radarange oven in 1947 based on microwave radio frequency, to day's sleek models with hardly 1100 watts energy load and looking almost like a small television set in a kitchen has come a long way to capture the imagination of every house holder. From just 1% of families owning a microwave oven in 1971 in the US, to day more than 90% have this modern gizmo improving the quality of their lives dramatically during the last 3 decades. Most microwave ovens operate under 2450 Mega Herz frequency which is universally recognized as a ISM band (Industrial, Scientific, Medical) radio frequency reserve for purposes other than communication. Out of the four ISM bands of 24125, MHerz, 5800MHerz, 2450 MHerz and 915 MHerz only 2450 MHerz is used for designing domestic microwave ovens. Recent emergence of 915 MHerz as an attractive alternative for large scale food processing has opened up opportunities for deploying this technology for heating and sterilization of many food products. Here is a report highlighting the importance of this technology to the industry.

"For decades, realizing the promise of rapid sterilization using microwaves has been a dream of the shelf-stable food industry.  Washington State University in collaboration with Natick Soldier Center formed an industrial consortium to obtain regulatory acceptance for 915 MHz single-mode microwave sterilization.Upon receiving that acceptance, the technology was licensed to Food Chain Safety who developed the technology into a commercial reality.  Rob Wilson, CEO Food Chain Safety said, "This MATS-B installation represents the culmination of years of development work and the start of an exciting new era in food processing."Major benefits of the MATS microwave sterilization system:• It delivers food that not only looks better but also tastes much better than canned foods. • Maintains nutritional value of the food.• Uses high-power microwave energy to heat packaged food to sterilization in a fraction of the time required with traditional canning processes. • Consistently heats products in a repeatable, measurable pattern. • The continuous process allows manufacturers to achieve higher throughput and lower production costs and provide workers with better work environments vs. traditional canning operations. • The new preservation technology offers great opportunities to create new and high quality products that are not possible with conventional methods".

It is not that microwave heating technology was not being used by the industry in the past but often the results have not been entirely satisfactory with energy costs being higher, non-uniform heating, design insufficiency and some food handling problems hampering its wide scale adoption. The new 915 MHerz technology is supposed to address these problems and with the approval from authorities for use of this frequency food industry may be tempted to use the microwave energy more widely in the coming years provided the system is cost effective. Though electric energy conversion into heat is only about 65%, microwave technology still is superior to other modes of heating. Models with capacity as high as 1800 kg per hour continuous processing now being offered, large scale processing is now possible.


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