Irradiation Pasteurization
Industry: Meat Product Manufacturing (NAICS 3116)
NAICS process:
Process Brief: The process of destroying microorganisms that could cause disease, usually done by applying heat to a food.
Energy source: nuclear radiant energy or electricity
Energy Intensity:
Irradiation pasteurization or cold pasteurization is a process that kills bacteria and other pathogens in food by exposing it to high-energy rays. Current application of irradiation pasteurization is with solid foods since liquids can be easily pasteurized in a conventional manner. In irradiation pasteurization, the food is passed through a radiation chamber or a conveyor belt, with no contact between food and radioactive materials. Presently, there are three types of radiation sources that have been approved for food pasteurization: cobalt-60 gamma rays, electron beams, and x-rays.
Cobalt-60 is the most commonly used source for food irradiation. A gamma irradiation facility consists of cobalt-60 rods in stainless steel tubes. The tubes are immersed in water and are raised into a concrete irradiation chamber when treating food. Cobalt-60 has several advantages including deep penetration and uniform dose. However, it also has several disadvantages including frequent replenishment of cobalt-60, and food treatment is relatively slow. Because the source is radioactive, a gamma irradiation facility is regulated by the Nuclear Regulatory Commission, and a special nuclear material handling facility is required.
Electron beam generators produce electron beams with an electron beam linear accelerator. Electricity is used generate the e-beams in these facilities. Electron beam generators offer several advantages including ability to be switched on or off as needed, do not require replenishment of irradiation source, and the absence of radioactive waste. There are also disadvantages including low penetration depth, high power requirements, and complexity.
In X-ray irradiation facilities, electron beams are converted to x-rays. The x-rays are then focused on the food target. This type of irradiation pasteurization is similar to the electron-beam-irradiation pasteurization. The difference between electron beam and x-ray pasteurization is penetration. X-rays are very effective on large or irregularly shaped products.
Source: Overview GRI-03/0075;