Hidemi Izumi, Ayano Inoue, VIII International Postharvest Symposium, Cartagena, 21-24 June 2016
Electrolyzed water containing 10-60 ppm available chlorine is being used in some commercial plants as an alternative disinfectant to sodium hypochlorite because it may be more effective without any damage to the product. In 2012, electrolyzed middle acidic water (pH 2.7-5.0) was approved as a food additive by the Ministry of Health, Labor, and Welfare of Japan in addition to electrolyzed strongly acidic water (pH<2.7), weakly acidic water (pH 5.0-6.5), and alkaline water (pH>7.5) that had previously been approved.
In this study, effects of the four types of electrolyzed water containing 30-50 ppm available chlorine on fresh-cut lettuce, cabbage, cucumber, and welsh onion were determined based on bacterial enumeration and identification.
The fresh-cut vegetables had 5.1-8.0 log CFU/g for mesophiles and 3.4-7.0 log CFU/g for coliforms, with the counts being higher in cucumber or welsh onion than in lettuce or cabbage.
The bacterial flora of fresh-cut vegetables was comprised of soilborne organisms such as Arthrobacter, Bacillus, and Curtobacterium and phytopathogenic organisms such as Enterobacter, Pantoea, and Psedomonas, except that welsh onion predominantly contained Enterobacteriaceae such as Leclercia, Rahnella, and Serratia.
Rinsing treatments reduced the counts of mesophiles or coliforms on all fresh-cuts by 0.4-1.5 logs relative to non-treated or water-treated samples regardless of the type of electrolyzed water.
When bacteria were isolated from each fresh-cut vegetable after treatment with the most effective type of electrolyzed water based on the reduction of bacterial counts, the weakly acidic water and middle acidic water reduced the number of bacterial genera or species detected in fresh-cut lettuce and cucumber, respectively, while the strongly acidic water and alkaline water did not reduce the diversity of bacterial flora of fresh-cut cabbage and welsh onion, respectively.
These results indicate that any electrolyzed water reduced the bacterial counts on fresh-cut vegetables, but the effectiveness on bacterial flora differed with type of water and vegetable.
Bactericidal effect of four types of electrolyzed water on fresh-cut vegetables
Hidemi Izumi, Ayano Inoue
Fac of Biol-Oriented Sci and Technol, 930 Nishimitani, Kinokawa, Wakayama 649-6493, Japan
VIII International Postharvest Symposium, Cartagena, Spain, 21-24 June 2016
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