COLD PLASMA – A NOVEL TECHNIQUE IN FOOD PRESERVATION

Food is anything edible and provide nutrients to human growth. Food spoilage is the major problem where microorganisms enter from surrounding environment. Spoilage microflora reduce the shelf life of foods by causing defects whereas pathogenic microflora cause diseases. This has led to the evolution of food preservation methods to inhibit the microflora. Heat treatments normally reduce the nutritive value of foods thus reduce the quality. Now a day’s consumers focus on non-thermal based foods. One such method catching up in present day is cold plasma technology. Cold plasma is a novel non-thermal food processing technology that uses energetic, reactive gases to inactivate contaminating microbes on vegetables, fruits, poultry and meat. This method uses electricity and a carrier gas, such as oxygen, nitrogen or helium. A wide array of cold plasma systems that operate at atmospheric pressures are under development. Reduction of more than 5 logs can be obtained for pathogenic bacteria such as Salmonella spp., Escherichia coli O157:H7, Listeria monocytogenes and Staphylococcus aureus. Effective treatment times can range from 120 sec to as less as 3 sec, depending on the food treated. The primary modes of action of cold plasma on microflora of food are due to UV light and reactive chemical products of cold plasma ionization process that denatured microbial cell proteins and mutated nucleic acids. Relatively early state of technology development, complexity of necessary equipment and largely unexplored impacts of cold plasma treatment on sensory and nutritional qualities of treated foods may be considered as limitations. Besides limitations, this area of technology is promising and subject of active research to enhance efficacy.