Combinations of intervention treatments resulting in 5-log10-unit reductions in numbers of Escherichia coli O157:H7 and Salmonella typhimurium DT104 organisms in apple cider.

The U.S. Food and Drug Administration (FDA) recently mandated a warning statement on packaged fruit juices not treated to reduce target pathogen populations by 5 log10 units. This study describes combinations of intervention treatments that reduced concentrations of mixtures of Escherichia coli O157:H7 (strains ATCC 43895, C7927, and USDA-FSIS-380-94) or Salmonella typhimurium DT104 (DT104b, U302, and DT104) by 5 log10 units in apple cider with a pH of 3.3, 3.7, and 4.1. Treatments used were short-term storage at 4, 25, or 35 degrees C and/or freeze-thawing (48 h at -20 degrees C; 4 h at 4 degrees C) of cider with or without added organic acids (0.1% lactic acid, sorbic acid [SA], or propionic acid). Treatments more severe than those for S. typhimurium DT104 were always required to destroy E. coli O157:H7. In pH 3.3 apple cider, a 5-log10-unit reduction in E. coli O157:H7 cell numbers was achieved by freeze-thawing or 6-h 35 degrees C treatments. In pH 3.7 cider the 5-log10-unit reduction followed freeze-thawing combined with either 6 h at 4 degrees C, 2 h at 25 degrees C, or 1 h at 35 degrees C or 6 h at 35 degrees C alone. A 5-log10-unit reduction occurred in pH 4.1 cider after the following treatments: 6 h at 35 degrees C plus freeze-thawing, SA plus 12 h at 25 degrees C plus freeze-thawing, SA plus 6 h at 35 degrees C, and SA plus 4 h at 35 degrees C plus freeze-thawing. Yeast and mold counts did not increase significantly (P < 0.05) during the 6-h storage at 35 degrees C. Cider with no added organic acids treated with either 6 h at 35 degrees C, freeze-thawing or their combination was always preferred by consumers over pasteurized cider (P < 0.05). The simple, inexpensive intervention treatments described in the present work could produce safe apple cider without pasteurization and would not require the FDA-mandated warning statement.