Sunday, January 23, 2011


If there is ever a clean food preservation technology available to mankind, irradiation process eminently qualifies for that spot. Though many countries have approved irradiation as a safe process to kill bacteria and other pathogenic microorganisms that spoil food, its wide scale use at the industry level is constrained by many practical problems. As many a consumer identifies irradiation as related to the destructive and deadly "Hiroshima" bombs which killed and maimed thousands of people, there is an understandable reluctance to "accept" foods undergoing irradiation process. All governments are moving cautiously in this area and irradiation is slowly being used in some selected cases with large benefits flowing from it. It is against this background that new approaches are being tried out to reduce radiation doses as much as possible to allay the misplaced fears of some consumers. The recently reported use of modified atmosphere packing (MAP) in combination with irradiation seems to be achieving this purpose.

"A new research has developed a method, which could significantly reduce the amount of irradiation needed to kill 99.99 percent of Salmonella, E.coli and other pathogens on fresh produce. A team of Texas AgriLife Research engineers found that by packing produce in a Mylar bag filled with pure oxygen and her colleagues found they could almost half the amount of radiation needed to kill those pathogens. Reducing the amount of radiation is not so much a safety measure as it is a way to preserve quality of the produce, said Carmen Gomes, AgriLife research food safety engineer. The U.S. Food and Drug Administration recently approved the use of irradiation at dosages of up to 4,000 Gray on leafy greens such as spinach, Gomes said. A Gray is a measure of ionizing radiation dose and it is equal to the absorption of 1 Joule of ionizing radiation by 1 kilogram of matter. "That dosage was determined as what was necessary to achieve an 100,000-fold reduction of such pathogens as E. coli O157:H7 and salmonella. However, we know based on previous research conducted by our group that above 1 kilo Gray (1,000 Gray) the quality of leafy vegetables starts to decay and they lose their freshness," noted Gomes. A 100,000-fold reduction corresponds to a 99.999 percent kill rate, according to Dr. Rosana Moreira, another member of the team".

Though the scientists claim that reducing the dosage serves a more useful purpose, viz. preserving the textural quality of crops like fresh greens, it is note worthy that a 50% lower dosage is able to achieve the same result when MAP is used before subjecting to irradiation process. Probably it is time for organizations like FAO, WHO and others to promote irradiation technology as the most important technique to prevent or reduce the massive food losses on a significant scale in the coming years. The logistics involved in making available low cost irradiation equipment must be addressed on priority so that majority of the industry can afford to establish the required facilities at minimum investment.


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