Inactivation of bacterial vegetative cells, spores, and viruses to ensure food safety
ジョージア大学 農環境学部 食品科学工学科(米国)
Department of Food Science & Technology, The University of Georgia(U.S.A.)
Professor Yen-Con Hung
Ensure the safety of food we consumed is a most for every food producers, processors, distributors, and restaurant operators. However, ensuring microbiological safety (e.g. pathogenic bacteria, spores, and viruses) is more difficult than chemical safety (e.g. toxins, heavy metals, or pesticides) due to microorganism can growth under favorable conditions. Electrolyzed (EO) water is a non-thermal treatment and has been demonstrated can inactivate food-borne pathogens, spores, and viruses on most of the foods. This report will provide a summary on the efficacy of EO water to ensure food microbiological safety
Study have been conducted and found neutral pH EO water (NEO) at 155 mg/L available chlorine concentration (ACC) reduced Escherichia coli O157:H7 and Salmonella Typhimurium DT 104 on romaine lettuce by 4.2 and 5.9 log CFU/g, respectively while reduction on iceberg lettuce were 3.2 and 4.6 log CFU/g, respectively. Washing tomatoes for 10 min achieved greater than 6 and 8 log CFU/tomato reductions on E. coli O157:H7 and S. Typhimurium, respectively. All pathogens were completely inactivated in NEO water wash solutions. No detrimental effects on the visual quality of the produce studied were observed. In addition, the sporicidal effect of acidic EO water (AEW) and slightly acidic EO water (SAEW) were tested on Bacillus subtilis and Bacillus cereus spores. The reduction of spore significantly increased with increasing ACC and treatment time (p<0.05). Non-detectable level of B. cereus spore in suspension was found within 2 min after exposure to both type of EO waters containing 120 mg/L ACC, while only SAEW at 120 mg/L and 2 min treatment achieved greater than 6 log reductions of B. subtilis spore. Both types of EO water with ACC of 60 mg/L and 6 min treatment achieved a reduction of B. subtilis and B. cereus spores to non-detectable level. AEW was also proven effective and generally killed more murine norovirus (MNV-1) and hepatitis A virus (HAV) in suspension than SAEW. ACC at 30 to 40 mg/L for 1 min achieved inactivate of MNV-1 and HAV by 3-log PFU/ml or greater. The virucidal effect increased with increasing ACC.