Efficacy of ozonated water against various food-related microorganisms
Restaino L; Frampton EW; Hemphill JB; Palnikar P
R & F Laboratories, Inc., Bridgeview, Illinois 60455, USA.
Appl Environ Microbiol, 61: 9, 1995 Sep, 3471-5
Abstract:
The antimicrobial effects of ozonated water in a recirculating
concurrent reactor were evaluated against four gram-positive and
four gram-negative bacteria, two yeasts, and spores of Aspergillus
niger. More than 5 log units each of Salmonella typhimurium and
Escherichia coli cells were killed instantaneously in ozonated
water with or without addition of 20 ppm of soluble starch (SS).
In ozonated water, death rates among the gram-negative bacteria--
S. typhimurium, E. coli, Pseudomonas aeruginosa, and Yersinia
enterocolitica--were not significantly different (P > 0.05). Among
gram-positive bacteria, Listeria monocytogenes was significantly (P < 0.05)
more sensitive than either Staphylococcus aureus or
Enterococcus faecalis. In the presence of organic material, death
rates of S. aureus compared with L. monocytogenes and E. coli
compared with S. typhimurium in ozonated water were not
significantly (P > 0.05) affected by SS addition but were
significantly reduced (P < 0.05) by addition of 20 ppm of bovine
serum albumin (BSA). More than 4.5 log units each of Candida
albicans and Zygosaccharomyces bailii cells were killed
instantaneously in ozonated water, whereas less than 1 log unit of
Aspergillus niger spores was killed after a 5-min exposure. The
average ozone output levels in the deionized water (0.188 mg/ml)
or water with SS (0.198 mg/ml) did not differ significantly (P <
0.05) but were significantly lower in water containing BSA (0.149
mg/ml).