**5. Effects of gamma irradiation on quality of fresh produce**

Safety of irradiated foods involves four aspects: radiological safety, toxicological safety, microbiological safety, and nutritional adequacy. The Bureau of Foods Irradiated Food Committee (BFIFC) of Food and Drug Administration FDA established that more than 90% of all radiolytic compounds in irradiated foods were similar to those found in heating, drying, and freezing of food (Diehl, 1995 and FDA, 1988). Basing its recommendations on radiation chemistry, FDA has concluded that foods irradiated at dose levels up to 1 kGy and foods comprising no more than 0.01 % of daily diet irradiated at 50 kGy or less can be considered safe for human consumption without any toxicological testing (Diehl, 1995). Free radicals are formed when food is irradiated, but they are also formed by exposure to sunlight, frying, baking, grinding, and drying. In wet foods , free radicals disappear within a fraction of a second; in dry foods, the free radicals are much more stable and do not disappear as quickly (ACSH, 1988).

#### **5.1 Nutrition quality of irradiated fresh produce**

Irradiated foods are wholesome, nutritious, and nutrient losses are not significantly different from other alternative treatments. The extent of nutritional losses as a result of irradiation is comparable to or less than that of most other processing methods (Josephson and Peterson, 1983; Nawar, 1986). Generally, there is no effect of γ-radiation (up to 10kGy) on the nutrients of irradiated foods. In a previous study, papayas, rambutans, and Kau oranges were acceptable after subjecting to a quarantine level of 0.75kGy (Follet and Sanxter,

Gamma Irradiation for Fresh Produce 257

access to irradiated products, consumers are willing to purchase them in noticeably great

The principal economic challenge of food irradiation is the projecting of market demand for irradiated fresh produce. A strong market demand, will attract investors absorb the large up-front costs needed to support food irradiation. Definitely, economic considerations are some of the factors that slow the widespread use of food irradiation. As any other food process, food irradiation adds a few cents per pound to the cost of production

Contributing to the limited marketing of irradiated food in USA, is the insufficient food irradiation facilities. As of August 2000, there were only two facilities in the United States used primarily for gamma irradiation of food. (GAO-10-309R. 2010. Federal Oversight of Food Irradiation (http://www.gao.gov/new.items/d10309r.pdf). It is costly to build an irradiation facility**.** A commercial food irradiation plant is in the range of \$3 million to \$5 million, depending on its size and processing capacity. Consumer reception of novel food technologies depends on risks and benefits associated to the new technology and reachable alternatives. Some consumer are attracted to purchase irradiated produce by the discernment that irradiated it is safer. Irradiated produce tend to have longer shelf life hence less storage losses. The cost of irradiated food could be offset by benefits such as keeping a product fresher longer and enhancing its safety (http://ag.arizona.edu/pubs/health/

Labeling of irradiated food has been considered indispensable in order to inform the consumers. Labeling laws of irradiated foods differ from country to country. In the U.S., as in many other countries, irradiated food are labeled as "Treated with irradiation" or "Treated by radiation" and require the use of the radura symbol at the point of sale in (Xuetong et al, 2007). Fresh produce should have the radura symbol displayed at the point of sell. For fruits and vegetables, radura symbol can be on each piece, on the shipping container, or on a sign near the merchandise. Analytical methods are used by government and regulatory agencies to determine irradiated foods in the market place (CODEX STAN 231, 2003)*.* Using these methods, existing labeling principles are imposed and consumers' confidence is

Consumers' knowledge about food irradiation is insufficient and therefore, education is desired to improve the acceptance of irradiated food by the public. Consumers are confused over what food irradiation and studies time and again display that when provided with science-based information, a high percentage of consumers favor irradiated foods. Food irradiation, pasteurization, canning, freezing, and drying are means of treating food in order to make it safer to eat and longer lasting (Satin, 1993). Despite its advantages, consumer knowledge about it is very limited. Many consumers' fears or misunderstanding of food irradiation are from reports of nuclear incidents at Hiroshima (Japan), Chernobyl (USSR),

(http://www.fipa.us/q%26a.pdf Food Irradiation Processing Alliance).

numbers (Bruhn, 1995).

az1060.pdf.

strengthened

**6.4 Consumer education** 

**6.2 Gamma Irradiation and cost of food** 

**6.3 Regulatory approval and labeling** 

2002). According to Scott J. S, and P. Pillai, 2004, **v**itamins have been shown to keep considerable levels of activity post irradiation. In general, proteins, lipids, and carbohydrates quality is not get affected as a result of irradiation (Thayer, 1990; Thayer et al., 1987; WHO, 1999). The nature and extent of the effects of ionizing radiation on nutrients depends on the composition of food, radiation dose, and modifying factors such as temperature and presence or absence of oxygen. It has been documented that minerals are also stable to irradiation ((Diehl, 1995). According to a report by Fan and Sokorai, 2002, irradiation can reduce vitamin C in some vegetables, but the decrease is usually inconsequential and does not exceed the decline seen during storage. Research on vitamin B6 has shown less destruction of this vitamin in products sterilized by ionizing energy than by heat (CAST, 1986). Follet and Sanxter (2002) studied the tropical fruits and found papayas, rambutans, and Kau oranges were acceptable when treated with a quarantine level of 0.75kGy (minimum dose required is 0.25 kGy). Irradiation is also reported to increase phenol compounds of certain vegetables consequently increasing their antioxidant ability (Fan, 2005).

Fresh produce may loss firmness after irradiation (Gunes et al., 2000; Palekar et al., 2004). However, the softening of fresh produce can be lessened by combining different treatments. According to Gunes et al., 2000; Prakash et al., 2007, dipping diced tomatoes and fresh-cut apples in a calcium solution prior to irradiation prevents the softening of the tissue.
