Fate of E. coli O157:H7, Salmonella spp. and potential surrogate bacteria on apricot fruit, following exposure to UV-C light

Some soft fruit, such as tree-ripened apricots, cannot be washed with aqueous sanitizers, due to their innate softness and delicate surfaces. In this study, ultraviolet-C (UV-C) light was investigated for its efficacy in inactivating 4–5 individual strains of Escherichia coli O157:H7 and Salmonella spp. on apricots, in addition to a four-strain composite of Shiga toxin-negative E. coli O157:H7 and a cocktail of three attenuated strains of Salmonella Typhimurium and Salmonella Typhimurium LT2. Also, the survival of E. coli O157:H7 and Salmonella spp. after exposure to 74 and 442mJ/cm² of UV-C was evaluated during post-UV storage at 2 and 20°C. The fruit was spot inoculated and the areas (ca. 1.5cm²) of fruit surface with the inoculated bacteria were exposed to UV-C at 7.4mW/cm². E. coli O157:H7 and Salmonella spp. populations decreased rapidly (1–2 logs) (P