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Spectrum of activity and rate of kill of acidified sodium chlorite |
N. A. MINER, MicroChem Laboratories, Inc., 7423 Airport Frwy., Fort Worth, TX 76118 Acidified sodium chlorite (ASC) is formed by reaction between sodium chlorite (NaClO2) and citric acid. ASC is an antimicrobial chemistry that has been used for many years as a broad-spectrum disinfectant for non-porous surfaces. ASC was recently approved as an antimicrobial agent for pathogen reduction and shelf life extension for poultry, raw agricultural commodities, red meats, and seafood. We studied the rate-of-kill in vitro of eleven food-borne pathogens by undiluted ASC (1:1), and ASC diluted with citric acid 1:10 and 1:100 . One ml of the bacterial cultures containing 5% calf-serum was added to 49.0 ml of ASC in an Erlenmeyer flask in a water bath at 20 C. After various exposure times, the ASC-bacteria mixture was sampled for surviving bacteria. More than six log 10 of Salmonella spp.(S. enteritidis, S. typhimurium, S. heidelberg, S. mission, and S. montevideo) were killed within 30 sec by ASC 1:1 and 1:10 at 20 C. More than six log 10 of E. coli ATCC 11229 and E. coli 0157:H7 were killed within 30 sec by ASC 1:1 and 1:10 at 20 C. More than five log 10 ( the highest concentration available) of Campylobacter coli and C. jejuni were killed within 30 sec by all concentrations of ASC. More than five log 10 of Listeria monocytogenes were killed by ASC 1:1 and 1:10 within 30 sec. Bacillus cereus is a spore-forming bacteria. About three log 10 of this culture population was killed by all concentrations of ASC within about 5.0 min, and thereafter a fraction of the population, possibly spores, resisted ASC diluted 1:10 and 1:100. The entire culture of B. cereus was killed within 30 min by undiluted ASC. Except for the Campylobacter spp., the other test bacteria were variously resistant to ASC 1:100, but still killed with longer exposure times. We conclude that ASC rapidly kills suspensions of food-borne pathogenic bacteria.
Session 91, Acidified sodium chlorite - an antimicrobial intervention for the food industry
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