Wednesday, June 9, 2010


Fear of pathogens in foods invariably tempts the processors for over kill at the expense of texture and other sensory quality parameters. Such changes in the food during processing can be drastic if thermal processes are used for sterilizing food products churned out by the industry. Such changes can be more serious in the case of low acid foods where Thermal Death Time (TDT) and lethality value assume critical levels, requiring compromise on the sensory quality for the sake of safety from viable pathogens. In contrast fruit juices and beverages with low pH or comparatively high acidity can be sterilized with much less heat, though the processed products will have inferior acceptability score. Here comes the role of non-thermal processing technologies which can preserve their initial quality during processing delivering a better product to the consumer. But destruction of nutrients due to thermal processing has never been considered crucial, though heat can adversely affect many temperature sensitive nutrients.

"Traditionally, fruit juices are pasteurized at temperatures below 100ÂșC for seconds or up to a few minutes. Although this is a short heat treatment, states the article, loss of nutritional and organoleptic properties is normally associated with conventional thermal pasteurization. The authors said that non-thermal processing technologies such as ozone represent a preferred alternative method for juice processors to produce a minimally processed food with minor quality changes. The FDA's approval of ozone as a direct additive to food in 2001 triggered interest in ozone applications development, and industry guidelines for apple juice and cider were published by the FDA in 2004, which the authors said highlighted gaps in the scientific knowledge".

Though Ozone sterilization is advocated in preference to thermal processing, how far it is effective for different products is a question mark that needs closer scrutiny. As Ozone is a reactive oxidizing agent because of its ability to produce nascent oxygen, its influence on flavors that are oxygen-sensitive also is an issue to be addressed. Probably use of Ozone may be more sensible in food preservation as a part of a "hurdle technology" system combining acidity, salt, sugar, heat, alcohol etc. Further studies only can bring out the universal applicability of Ozone as a regular sterilant in different types of foods.


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