Extension of shelf life of pasteurized trim milk using ultraviolet treatment

The demand for minimally processed foods has increased in the last few years and gains high acceptability among consumers as it has better nutritional value than highly processed foods. Pasteurized milk is minimally processed and consumed largely for its fresh taste and higher nutritional value compared to ultrahigh temperature (UHT) and powdered milk. However, one of the constraints is its limited shelf life under refrigeration, as it cannot retain quality and safety for more than 14 days. Nonthermal technologies can extend the shelf life of milk while using low energy. Ultraviolet (UV-C) is well known to inactivate spores as well as vegetative cells. In this study, it was shown that 2.64 J/ml of UV-C treatment applied on pasteurized trim milk can extend shelf life up to 53 days under refrigeration. This finding was also supported by the inactivation of 3.40 +/- 0.14 log of thermoresistant Geobacillus stearothermophilus spores (ATCC 7953) in UHT (or sterilized) trim milk with similar UV-C operating conditions. Therefore, microbial study together with physicochemical properties demonstrated that pasteurization followed by UV-C can enhance the shelf life of trim milk considerably.