LAUSR

This research study was based on ultraviolet (UVC) light and a combination of UVC-ozone treatments that have recently received attention from the beef processing industry as antimicrobial interventions that leave no chemical residues on products. The objectives were to evaluate effectiveness of UVC and UVC in combination with gaseous ozone treatments for inactivation of pathogenic bacteria on fresh beef and the impact on fresh beef quality. Fresh beef tissues were inoculated with cocktail mixtures of Shiga toxin-producing Escherichia coli (STEC) strains (O26, O45, O103, O111, O121, O145, and O157:H7), Salmonella, and Listeria monocytogenes. Inoculated fresh beef tissues were subjected to UVC or UVC in combination with gaseous ozone treatments at 106 to 590 mJ/cm2. Study results showed that UVC treatment alone or UVC in combination with ozone reduced populations of STEC, Salmonella, L. monocytogenes, and aerobic bacteria ranging from 0.86 to 1.49 log, 0.76 to 1.33 log, 0.5 to 1.14 log, and 0.64 to 1.23 log, respectively. Gaseous ozone alone reduce population of E. coli O157:H7, Salmonella, L. monocytogenes 0.65, 0.70, and 0.33 log, respectively. Decimal reduction times (D-value) for serogroup of STEC, Salmonella and L. monocytogenes on surfaces of fresh beef indicated that UVC treatment in combination with ozone was more effective (P ≤ 0.05) in reducing pathogens on surfaces of fresh beef than treatment with UVC light alone. Exposure to UVC or UVC with gaseous ozone did not have a deleterious effect on fresh meat color and did not accelerate the formation of oxidative rancidity. The findings suggest that UVC and UVC in combination with gaseous ozone can be useful in enhancing the microbial safety of fresh beef without impairing fresh beef quality.