Pros And Cons Of Food Irradiation

Preservation is based predominantly on delaying or preventing the growth of microorganism, and less commonly, with the exception of thermal processing, an outright killing that is more typical of disinfection (Russell et al, 1999). There are several forms of food preservation methods such as smoking, freezing, dehydration, pasteurisation and as referred to in this essay, irradiation. Foods are processed and preserved to provide the consumer with a higher standard of product over a longer period of time, thus ensuring the product is of a quality nutritional standard for the shelf life period, during transportation and storage.

The radiation used in food irradiation is called ionising radiation, this is due to the knocking of electrons from

Foods such as beef, pork, poultry, fresh fruit and vegetables, seeds for sprouting, shellfish and crustaceans are all approved for irradiation by the United States Food and Drug Administration (FDA), along with the World Health Organisation (WHO), U.S. Department of Agriculture (USDA) and the Centers of Disease Control and Prevention (CDC) after 30 years of ongoing research. Neither Cobalt 60 nor Cesium 137 give off neutrons, which means that they do not make anything around them radioactive. Using Cobalt 60 or Cesium 137 in gamma radiation ensures the high energy photons can penetrate the food to a depth of several feet, hence why rooms where this method of ionising radiation must have walls at least two meters in thickness. When the radioactive material sources are not in use, they are usually stored in a water – filled pool below the cell (Webb and Lang, 1990).

Webb and Lang (1990) describes the process of irradiation generally consisting of the food being loaded by workers and brought into the irradiation cell on a conveyor where the food is exposed to the radioactive material for a defined period of time and then removed from the conveyor and stored at the required temperature, which is usually low, before being dispatched to be

In the radiation of onions, those who were exposed to 10 Krads of Co60 gamma irradiation for varying times and stored in cold storage and room temperature to see the effect, over three months only two – three sprouts in each onion bulb (Farooqi and Donini, 1976). Another study in India found that the exposure of onions to the gamma radiation for a short period of time killed microbes and increased the shelf life. This allowed for a crop of onions to have a shelf life of more than six months in storage after radiation (Biswas, 2015). Furthermore, it was found that when onion bulbs were gamma irradiated at 0.10 kGy and stored at a low temperature under ambient conditions, after four months 1-15% irradiated onions were rotting, whereas 5-64% onions were rotting when unirradiated under the same conditions (Nouri, 2001). When processing onions they are brought from harvesting and stored in ambient conditions until the irradiation takes place, they are then conveyed into an irradiation chamber with thick concrete walls ensuring no rays escape, and the gamma ray source is taken out of the water pool. The onions are then exposed to a low dose (up to 1kGy) of gamma rays, known as radurization, which can inhibit insects and parasite reproduction and inhibit rotting therefore extending shelf life. The onions are then conveyed out of the irradiated chamber to be