Macrowave Radio Frequency Co.

Food Safety / Pasteurization and Disinfestation Systems from RFC

Since the early 1960s Radio Frequency Company has been marketing its Macrowave™ heating systems for the pasteurization and disinfestation of food products. Pictured is a 30kW Macrowave™ Pasteurization System for granular food products such as green peanuts and various types of grain, which was designed and patented by RFC's founder, Mr. Joshua G.D. Manwaring on July fourth 1967. Joshua's design featured a rotary product feeding tube to prevent agglomeration, and a closed loop temperature control system, which were both considered cutting-edge technology at that time.

Pasteurization and Disinfestation Systems

Radio Frequency Aparatus

In the 1980s Macrowave™ Systems were introduced to the manufacturers of cigars and cigarettes for the control of tobacco beetles. Since that time, tobacco beetles and other agricultural insects, such as confused flour beetles, have been consistently eradicated by Macrowave™ heating systems in all life stages, adult, pupae, larvae and eggs. Test data indicates that total mortality is achieved with RF heating at temperatures as low as 136°F.

Improved Stem Temperature/Beetle Mortality Results

Beginning in 1990, larger Macrowave™ Systems were supplied for the pasteurization of fishmeal in fifty and one hundred pound bags, as well as for bulk product as it is unloaded from the shipping terminal. A clean supply of fishmeal free from salmonella is desired by the pet food and aquaculture industries and radio frequency heating provided a fast and efficient means to process the product. A 75kW system is pictured below processing the meal in 50lb bags.

75kW Bag Heater

In 1994, RFC installed the first continuous flow treatment system for the pasteurization of fishmeal. In the photos below, bulk product is vacuumed from river barges into a silo. The Macrowave™ System, located at the bottom of the silo, is then fed by an auger into a product feed hopper for treatment. After processing, the material is fed to a separate clean silo. Proximity sensors in the feed hopper signal the auger when to add more product.

Pasteurization of fishmeal

In March of 2006, RFC worked closely with the Almond Board of California to develop a Macrowave™ Pasteurization System capable of providing a 5 log reduction for a particularly dangerous form of salmonella, Enteritidis PT30. RFC successfully met this challenge by developing and demonstrating the Macrowave™ HydraTherm Pasteurization System.

Figure 11: Trial III Log Reduction Results

Systems for bagged products have also been provided for such products as pea starch, various bean protein products, flax meal, nuts, spices and wheat flour and other agricultural products as well as prepared food items.

How it works

In a radio frequency Pasteurization System, the RF generator creates an alternating electric field between two electrodes. The material to be treated is conveyed (in bags or in bulk) between the electrodes where the alternating energy causes polar water molecules in the material to continuously reorient themselves to face opposite poles much like the way bar magnets behave in an alternating magnetic field. The friction resulting from molecular movement causes the material to rapidly heat throughout its entire mass.

The animated illustration below depicts a radio frequency heating system with material between the electrodes. The figures in the material represent polar water molecules. Note how the polar water molecules move to face the oppositely charged electrode when the electric field reverses as the RF generator oscillates, as shown by the moving wave form.

Animated image of RF Pasteurization System

The very rapid and precisely controllable RF heating process offers the advantages of reduced processing times, maintenance of functionality, consistent log reductions, and simplified process control.

As an alternative to noxious gasses or carbon producing thermal techniques, Radio Frequency (RF) heating is a highly efficient "direct" form of heating such that no energy is wasted heating large volumes of air or preheating the system itself. The technology is "instant-on, instant-off" using energy only during the treatment process.

Radio Frequency Company has developed a line of Macrowave™ Pasteurization Systems that operate at 40MHz where the depth of penetration and uniformity of heating are optimized, thereby ensuring effective microbe kill and avoiding the deleterious effects on product quality from prolonged exposure to high temperatures.

To investigate if your product can benefit from the Macrowave™ Pasteurization Process, tests can be run at RFC's laboratory in Millis, Massachusetts both in bagged or bulk form. Inoculated samples can be processed with fiber optic thermal probes so that thermal death curves can be plotted and evaluated for efficacy. The photo below depicts products being tested at RFC in both bagged and bulk form.

Bagged and Bulk Products Being Tested

As the emphasis on Food Safety and Pasteurization continues to grow, so do RFC's Macrowave™ Installations. Pictured below is a hopper-fed, 400kW RF Pasteurization System capable of treating 25,000lbs per hour and achieving a greater than 5log reduction.
Typical Macrowave™ Salmonella Challenge Study Results

400kW Macrowave™ Ultra-Series Flour Pasteurization System

To conduct challenge studies at RFC, for our prospective customers without in-house micro capabilities, RFC will happily coordinate you with Lapuck Laboratories, Inc. Lapuck Laboratories is conveniently located to Radio Frequency Company and experienced in many areas of food safety. Founded in 1966, Lapuck is a privately held, independent, ISO 17025 accredited laboratory offering comprehensive testing and consulting services.   Lapuck Laboratories, Inc

LAPUCK Laboratories LogoCertified and registered by various companies

For complete information on RFC's available systems and product consultation, please contact us.

See the new Ultra-Series Macrowave™ Pasteurization System here.

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