Effects of gamma irradiation on the shelf-life of a dairy-like product

Abstract

This study was aimed to assess the effect of irradiation on the shelf-life of pseudo-dairy food product consisting of different concentration levels of the structural and energy-giving caloric component macronutrients (protein, fat and carbohydrate). Gamma irradiated products (1kGy, 3kGy, 5kGy and 10kGy) were compared to the current procedure used by the industry of non-irradiated dairy products. The study looked at the impact of different treatments on storage quality in respect to physicochemical (pH, acidity, macronutrients), and microbiological properties [total viable count (TVC)]. The products were aseptically packaged in plastic containers and analysed at regular weekly intervals up until 100 days during refrigerated storage at 4 ± 1°C. The storage period did not bring about any significant change in physicochemical properties of the products throughout the period of study while the TVC displayed a linear regression for irradiated products stored at 4 ± 1°C as well as the control (non-irradiated). At the end of the shelf-life trial (benchmarked at log 4.3 CFU/g), the total viable count did not exceed log 3.94 CFU/g for samples treated at 10kGy after 100 days of analysis. These observations indicated that the product could be safely stored aerobically for > 100days (10 and 5kGy), 56days at (3kGy), 42 days at (1kGy) for the irradiated samples' and 14–28 days for the non-irradiated samples without much change in physicochemical and microbiological properties using refrigerated storage.