title: 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.
abstract: 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.
authors.affiliation: Department of Food Science, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA.
authors.forename: H E
authors.initials: HE
authors.lastname: Uljas
authors.forename: S C
authors.initials: SC
authors.lastname: Ingham
mesh_terms: D000143:Acids; D001628:Beverages / Q000382:microbiology*; D015169:Colony Count, Microbial; D004927:Escherichia coli Infections / Q000517:prevention & control; D019453:Escherichia coli O157 / Q000302:isolation & purification*; D005511:Food Handling; D005615:Freezing; D005638:Fruit / Q000382:microbiology*; D005658:Fungi / Q000302:isolation & purification; D006801:Humans; D006863:Hydrogen-Ion Concentration; D012449:Safety; D012478:Salmonella Food Poisoning / Q000517:prevention & control; D012486:Salmonella typhimurium / Q000302:isolation & purification*; D013696:Temperature; D015003:Yeasts / Q000302:isolation & purification
chemical_list: D000143:Acids