Hot and Chilled Water Treatments to Inactivate Escherichia Coli O157

Hot and chilled water treatments to inactivate Escherichia coli O157:H7 and Salmonella in mung bean seeds.
Institute of Food Technologists Annual Meeting, New Orleans, Jun 30, 2008, Poster Session 52-02,Latiful Bari, National Food Research Institute, Tsukuba-City, Japan; Yasuhiro Inatsu, National Food Research Institute, Tsukuba-City, Japan; Seiichi Isobe, National Food Research Institute, Tsukuba-City, Japan; Shinnichi Kawamoto, National Food Research Institute, Tsukuba-City, Japan  

The majority of the seed sprout related outbreaks have been associated with Escherichia coli O157:H7 and Salmonella. Therefore, it is necessary to find an effective method to inactivate these organisms on the seeds prior to sprouting. This study was conducted to assess the effectiveness of various hot water treatments to inactivate E. coli O157:H7 and Salmonella populations on mung beans seeds intended for sprout production and to determine the effect of these treatments followed by dipping in chilled water for 30 sec on seed germination. Mung bean seed inoculated with four-strain cocktails of E. coli O157:H7 and Salmonella were soaked into hot water at 800C and 900C with shaking for various periods of time followed by dipping in chilled water for 30 sec. The treated seeds were then assessed for the efficacy of the treatment in reducing populations of the pathogens and the effects of the treatment on germination yield. After inoculation and air-drying, 6.08 ± 0.34 log CFU/g E. coli O157:H7 and 5.34 ± 0.29 log CFU/g Salmonella were detected on the seeds. Hot water treatment at 900C for 90 seconds followed by dipping in chilled water for 30 sec, no viable pathogens were found, no survivors were found in the enrichment medium and during the sprouting process. The germination yield of the seed was not affected significantly. Therefore, hot water treatment followed by dipping in chilled water for 30 sec could be an effective seed decontamination method for mung bean seeds intended for sprout production.