Food irradiation, commercial applications

Besides the pioneering implementations of specific low-dose applications as well as the widely utilized irradiation of spices now, mentioned in Secs. 4.1, 4.2, and 4.9, small-scale commercial application of irradiation to ensure hygienic quality of food, especially those of animal origin, has been carried out in Chile, China, Indonesia, and Thailand in the past two decades. In the recent years, new commercial irradiators including some that are dedicated to food irradiation have been commissioned in Brazil (which plans to add up to 10 facilities in the coming years), China, India, Republic of Korea, Mexico, and Thailand [157]. 

Although a relatively new commercial process, food irradiation has been studied more thoroughly than any other food technology. More than 40 years of research have shown conclusively that there are no adverse effects from the consumption of irradiated food. In fact for many foods, preservation by irradiation has proved to be by far the best method. Table 4.4 summarises the general applications of food irradiation technology. 

Cobalt exists in valence states from 0 to 5, with the most stable (4-2 and - -3) being most common. While there is only one stable isotope of cobalt, there are a number of unstable isotopes. Two of these, cobalt-60 and cobalt-57, are in use commercially. Cobalt-60 is used for cancer treatment and for food irradiation. Cobalt-57 has research applications. 

Update on the U.S. and World Situation. A limited number of food products have been cleared since the early 1960s by the U.S. Food and Drug Administration for commercial irradiation and marketing. Table I lists these products (8). These clearances represent several applications of food irradiation with disinfestation the leading potential application. 

While 42 foods have been cleared by 36 countries for irradiation to date and 19 of these countries are irradiating 20 food items commercially, food irradiation around the world still faces a number of uphill hurdles which must be overcome before it can gain a foothold in the consumer market. These include (a) clear indication of industry interest and need in using a particular application (b) positive demonstration of economic feasibility ... 

The fission product and encapsulation plant (FPCE) to be built by Isochem, Inc.y in Washington state will produce fully encapsulated fission products for the commercial market. Among these, all of which are extractable from Hanford s plutonium process residues, is cesium-137, a 600-kv. gamma emitter of interest to the process irradiation industry. Isochem will offer cesium in large production quantities and low cost to irradiators of foods, woods, chemicals, etc. Its 30-year half-life promises economies in source array replenishment to compensate for decay. Cesium thus becomes an economic contender for current and planned irradiation applications. 

Commercial Products Division did not limit its attempt to develop its irradiation business to food and medical products. In the search for practical applications, its... 

Bactericidal processes which can be most effectively and practically used to eliminate salmonellae from foods appear to be mainly limited to the application of heat or of irradiation. As discussed by Mossel and Ley , ionising radiation is particularly technically attractive with its highly penetrative biocidal properties and because it can uniquely be used to terminally pasteurise previously frozen or packaged food products. On the theoretical basis of reducing the population of salmonellae by a factor of 10, i.e. 6 log cycles, the most probable effective dose (MPED) has been estimatedto be 0-4 0-2 Mrad (4 0 2 0kGy) and 0-25 Mrad has been shown to inactivate at least 3 log cycles of salmonellae on deep-frozen boiler carcasses under simulated commercial conditions A cautionary note was introduced by Urbain in 1978, however, who considers that salmonellae radicidation may be uneconomic unless universally required by government legislation and Davies Sinskey have shown that radiation-resistant mutants of S. typhimurium potentially exist and can be selectively isolated in extreme, cyclic irradiation circumstances. 

Since 1970 a new and broader approach to the safety question has been introduced and there is some hope of a breakthrough. In spite of the ever-increasing evidence of the potential commercial use of a process based on research and development work, industry will not be in a position to gain practical experience until the health clearance situation is simplified. This is particularly true in relation to the introduction of irradiated food into international trade when it is necessary for the various importing countries to agree on acceptability of the process before application in the exporting country can become an economic reality. 

Another potential application of radioactive species is in food preservation (Figure 18.4). It is well known that gamma rays can kill insects, larvae, and parasites such as trichina that cause trichinosis in pork. Radiation can also inhibit the sprouting of onions and potatoes. Perhaps most important from a commercial standpoint, it can extend the shelf lives of many foods for weeks or even months. Many chemicals used to preserve foods have later been shown to have adverse health effects, so irradiation is an attractive alternative. Finally, irradiation can destroy microorganisms such as E. coli (which explains its use in treating beef) and anthrax (which explains its use in sterilizing suspected mail). 

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