An overview of irradiation as a food preservation technique

Food irradiation is a process whereby food is exposed to a carefully measured amount of intense radiant energy, called ionizing radiation. The ionizing radiation has the ability to break the chemical bonds. Irradiation can kill harmful bacteria and other microorganisms in meat, poultry and seafood. Moreover, it can disinfest spices, extend shelf-life of fresh fruits and vegetables, and control sprouting of tubers and bulbs such as potatoes and onions; thus, can be used as a food preservation method. It is a safe process that has been approved by the U.S. Food and Drug Administration (FDA), and more than 60 of other national food control authorities for many types of foods. There are three types of ionizing radiation that can be potentially used in food irradiation including; Gamma rays from  Cesium 137 (137Cs) or Cobalt 60 (60Co), X-rays generated from machine sources operating at or below energy level of 5 MeV; and Electrons generated from machine sources operating at or below an energy level of 10 MeV (also known as E-Beam). During the radiation processing of foods, the doses are generally measured in kilograys (kGy = 1,000 Gy). The DNA is very sensitive to irradiation; therefore, food irradiation cause damage to the microbial cells through direct or indirect action on the DNA molecules. However, the accurate dose of food irradiation process is essential to ensure food preservation and safety. This review aimed to provide information on the principles of food irradiation, effect of irradiation on food contaminating microorganisms, and some limitations to its greater use as food preservation method in Nigeria.