Application of ultraviolet-C radiation to inactivate acid-and-desiccation stressed Salmonella enterica in young and mature coconut liquid endosperm mix beverage

摘要

The occurrences of outbreaks of infections due to consumption of unpasteurized fruit beverages, and the negative effects of heat treatment towards quality are features of the consumer demand paradox on safety and quality that the industry has to address. This study established the efficacy of ultraviolet-C (UV-C) treatment against acid-and-desiccation stressed Salmonella enterica; and applied and evaluated a process schedule with a recommended lethal rate of 99.999% against the target pathogen. Determinations of decimal reduction times revealed that suspension volume and flow property significantly affected inactivation of the test organism, which exhibited the greatest resistance to UV-C when suspended in 500 ml, non-agitated coconut beverage. A UV-C process schedule with a level of lethality of 5-log cycle reduction against the reference organism was then applied to the beverage. Quality evaluations showed that the pasteurization process resulted in significant color changes in the beverage. The process also significantly affected the microbiology of the beverage, but the population of spoilage microorganisms continuously increased during storage; surpassing microbial limits by the 2nd d of refrigerated storage. The sensory quality scores of the processed beverage were not significantly different from the non-processed control, and were higher than an established commercial brand. (C) 2014 Elsevier Ltd. All rights reserved.