CHAPTER ONE
1.1INTRODUCTION
Food Irradiation is the process of exposing food to ionizing radiation to disinfect, sanitize, sterilize, preserve food or to provide insect disinfestation. (wikipedia.org)
Food irradiation is sometimes referred to as cold pasteurization or electronic pasteurization to emphasize its similarity to the process of pasteurization. Like pasteurization of milk and pressure cooking of canned foods, treating food with ionizing radiation can kill bacteria and parasites that would otherwise cause food borne diseases. (wikipedia.org; www.cdc.gov)
By irradiating food, depending on the dose, some or all of the microbes, fungi, viruses or insects present are killed. This prolongs the life of the food in cases where microbial spoilage is the limiting factor in shelf life. Some foods (e.g. herbs and spices) are irradiated at such high doses (5kGy or more) that they show microbial counts reduced by several orders of magnitude. It has also been shown that irradiation can delay the ripening or sprouting of fruits and vegetables and replace the need for pesticides.
Studies have shown that when Irradiation is used as approved on foods:
·                    Disease-causing germs are reduced or eliminated.
·                    The food does not become radioactive
·                    Dangerous substances do not appear in foods
·                    The nutritional value of the food is essentially unchanged. (www.cdc.gov)
In the food industries, specific types of radiation treatments are used, they are Radurization, Radicidation, and Radappertization. However, in the actual process of irradiation, three different irradiation technologies are used namely; gamma irradiation, electron-beam irradiation and x-ray radiation. (www.cdc.gov)
The dose of irradiation is usually measured in a unit called the Gray, abbreviated (Gy). This is a measure of the amount of energy transferred to food, microbes or other substances being irradiated. To measure the amount of irradiation something is exposed to, photographic film is exposed to irradiation at the same time.
The killing effect of irradiation on microbes is measured in D-values. One D-value is the amount of irradiation to kill 90% of that organism. For example, it takes 0.3kGy to kill 90% of Escherichia Coli, so the D-value of E.coli is 0.3 kGy. (www.cdc.gov).
A distinctive logo has been developed for use on food packaging, in order to identify a product as irradiated. This symbol is called the “radura” and is used internationally to mean that the food in the package has been irradiated. (www.cdc.gov)