Irradiation

Food irradiation was the most important technological development in food processing since canning came into commercial use in the early 1880s.

Irradiation is the process of subjecting food to electron beams or gamma rays to kill bacteria. The major advantage is that food can be packaged either before or after treatment.

The United States has conducted an intensive irradiation research program since the end of World War II.

Most food losses are due to spoilage. One of the major reasons for spoilage is the action of microorganisms in the food. Intensive research shown that when gamma rays, given off by a radiation source are allowed to pass though food, the rays will kill or reduce the number of microorganisms in the food, thus preventing or delaying spoilage.

The radiation damages the bacteria so that it cannot reproduce. By killing the bacteria, spoilage is also delayed. The amount of radiation is not enough to make the food radioactive, only to kill bacteria.

Currently irradiation is used to sterilize medical supplies and cosmetics and a limited used to sterilize medical supplies and cosmetics and a limited number of foods.

Irradiation is the only way to kill E. coli O157:H7 besides heat.

The rays themselves are produced by an irradiator. This may either a radioisotope (a radioactive element such as cobalt-60 or cesium-137) or an electron accelerator. Both types have their advantages and disadvantages.
Irradiation