Reduction of escherichia coli 0157:H7 in fresh spinach, using lactic acid bacteria and chlorine as a multihurdle intervention

S. E. Gragg, M. M. Brashears

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16 Scopus citations


A 12-day shelf life study was conducted at 7°C to determine whether Escherichia coli 0157:H7 on spinach can be controlled effectively by selected strains of lactic acid bacteria (LAB) alone or in combination with chlorine as a multihurdle intervention. The multihurdle intervention consisted of both LAB and chlorine and was applied to spinach as a rinse and evaluated in comparison to LAB alone and chlorine and water rinses. Reductions achieved by all treatments also were compared with those observed for an inoculated control. The spinach was inoculated by submersion in a solution containing an E. coli 0157:H7 cocktail at 1.0 × 106''CFU/ml. LAB were applied postharvest at a concentration of 2.0 x K)* CFU/ml, and 200 ppm of chlorine was used for the chlorine rinse. All spinach samples were packaged in commercial packaging, held in a retail display case, and tested for E. coli 0157:H7 on days 0. 1.3. 6, 9. and 12 using the Neo-Grid filtration system and CHROMagar. Survival of LAB throughout the shelf life also was determined. Significant reductions in pathogen populations were achieved by water (P = 0.(X)OS), LAB (P < O.OOOl), chlorine (P < 0.0001), and multihurdle (P < 0.0001 ) treatments when compared with controls. The multihurdle treatment produced the greatest reduction from control populations, a reduction of 1.91 log CFU/ml. This reduction was significantly greater than that achieved with water (P < 0.0001), LAB (P = 0.0025), and chlorine (P < 0.0001) alone, indicating that the application of chlorine and LAB is most effective as a combination treatment. The results obtained from this study indicate that the industry standard chlorine wash may be more effective when applied in combination with LAB.

Original languageEnglish
Pages (from-to)358-361
Number of pages4
JournalJournal of food protection
Issue number2
StatePublished - Feb 2010


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