DETERMINATION OF THE MICROBIOLOGICAL QUALITY AND ACCEPTANCE OF SELECTED IRRADIATED PERISHABLE FOOD PRODUCTS DURING STORAGE

Food products such as bread, cakes and other delicacies are highly perishable products which are mainly deteriorate due to staling, moisture loss and microbial spoilage. More than 90% of mould contamination occurs during cooling, slicing, or wrapping operations. Studies were carried out to overcome arisen of the safe shelf-stable food and to evaluate the suitability of irradiation in preserving local sliced breads and bahulu cakes. Generally, these food products can be kept in room temperature only for one or two weeks respectively. Fresh packed products were obtained from local producers and irradiated at doses of 2.0 kGy, 5.0 kGy and 10 kGy, using 60Co gamma irradiation source at MINTec-Sinagama. The irradiated and non-irradiated samples were displayed at room temperature storage periods for 1 month. Microbiological analysis was carried out to determine status of bacteria (Total Plate Count) and fungi counts (cfu/g). Colour changes of the products were recorded using Colorimeter (Minolta) for lightness (L), redness (a) and yellowness (b) values. Acceptability of the irradiated products were determined through sensory evaluation by using 30 members (male and female) of untrained panellists. Results showed that irradiation at 2 kGy reduced the microbial loads (bacterial and fungal colonies) in the irradiated samples and no presence of microbes after irradiated at 5 and 10kGy. Nevertheless, after 1 month of storage, the microbial load increased in the control samples but remained low in the irradiated samples. Both samples irradiated at 2 kGy were more acceptable in sensory evaluation especially texture and taste and there was a significant change (P<0.05) in the lightness of the sample after irradiation. The samples become darker after irradiation at 10 kGy. These results demonstrated the ability of gamma irradiation for the decontamination of selected perishable food products and reliable process for food storage in commercial industry.