Use of Irradiation to Extend the Shelf Life of Dried White Oyster Mushroom (Pleurotus ostreatus)

Irradiation is an alternative technology to extend the shelf life of food-stuffs. White oyster mushroom (Pleurotus ostreatus) which is a perishable food stuff having a short shelf life. Effects of gamma irradiation at the dose of 5 kGy on the quality of dried white oyster mushroom during storage was observed. The objective of the experiment was to improve the hygienic quality and to extend the shelf life of dried white oyster mushroom using irradiation technology. Fresh mushroom was cleaned, sorted, washed, and drained. The mushroom was then dried in two ways, namely: sun drying method and electrical oven drying method. Dried mushroom was vacuum packed in polypropylene (PP) pouch then irradiated at a of dose 5 kGy and an unirradiated control was also applied. The vacuum packed samples was stored at low temperature (18-20oC) with a relative humidity (RH) of 65-70% and observed periodically every month up to 3 months of storage. The samples were analyzed according to the following parameters i.e, : total bacterial count, total mould and yeast count, moisture content, pH, aw, contents of protein, fat, carbohydrate, carotenoid and organoleptic properties, respectively. The results showed that irradiation at the dose of 5 kGy could eliminate significantly microbial growth 2 log cycle in the samples, while there were no changes in physico-chemical and organoleptic properties up to 3 months of storage, while control samples were still acceptable only up to 2 months of storage. (author)