Microbial changes in strawberries treated with gamma irradiation to improve their quality

ABSTRACT

The possibility to extend the fresh shelf-life of strawberries by gamma radiation in two different packaging materials was studied. The changes that took place in microbial population as a result of irradiation and cold storage of strawberries was also investigated. The weight loss was much more lower in the packages wrapped with non- perforated polyvinyl chloride [PVC] film in comparison with those covered with perforated polyethylene film which commonly used in exportation. Application of gamma irradiation almost inactivated Gram-negative bacteria, Pseudomonas and Enterobacteriaceae that caused a great reduction in total bacteria count, moulds and yeasts. The shelf-life of non-irradiated strawberries was only 10 days at 4C. Irradiation doses of 1 and 2 kGy extended the cold shelf-life of strawberries to 18 and 21 days, respectively, without any objectionable changes in its flavor and texture. Irradiation dose of 4 kGy delayed the onset of the mould growth on the surface of strawberries up to 30 days, however tissue softening of strawberries was observed