Fate of enterohemorrhagic Escherichia coli O157:H7 in apple cider with and without preservatives.
A strain of enterohemorrhagic Escherichia coli serotype O157:H7 isolated from a patient in an apple cider-related outbreak was used to study the fate of E. coli O157:H7 in six different lots of unpasteurized apple cider. In addition, the efficacy of two preservatives, 0.1% sodium benzoate and 0.1% potassium sorbate, used separately and in combination was evaluated for antimicrobial effects on the bacterium. Studies were done at 8 or 25 degrees C with ciders having pH values of 3.6 to 4.0. The results revealed that E. coli O157:H7 populations increased slightly (ca. 1 log10 CFU/ml) and then remained stable for approximately 12 days in lots inoculated with an initial population of 10(5) E. coli O157:H7 organisms per ml and held at 8 degrees C. The bacterium survived from 10 to 31 days or 2 to 3 days at 8 or 25 degrees C, respectively, depending on the lot. Potassium sorbate had minimal effect on E. coli O157:H7 populations, with survivors detected for 15 to 20 days or 1 to 3 days at 8 or 25 degrees C, respectively. In contrast, survivors in cider containing sodium benzoate were detected for only 2 to 10 days or less than 1 to 2 days at 8 or 25 degrees C, respectively. The highest rates of inactivation occurred in the presence of a combination of 0.1% sodium benzoate and 0.1% potassium sorbate. The use of 0.1% sodium benzoate, an approved preservative used by some cider processors, will substantially increase the safety of apple cider in terms of E. coli O157:H7, in addition to suppressing the growth of yeasts and molds.
Zhao
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Center for Food Safety and Quality Enhancement, University of Georgia, Griffin 30223.
Doyle
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MP
Besser
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D001565:Benzoates; D019817:Benzoic Acid; D001628:Beverages / Q000009:adverse effects*; D003092:Colitis / Q000209:etiology; D004926:Escherichia coli / Q000302:isolation & purification* / Q000472:pathogenicity; D005069:Evaluation Studies as Topic; D005516:Food Microbiology; D005520:Food Preservatives; D005517:Foodborne Diseases / Q000209:etiology / Q000517:prevention & control; D005638:Fruit / Q000382:microbiology*; D006463:Hemolytic-Uremic Syndrome / Q000209:etiology; D006801:Humans; D013011:Sorbic Acid
D001565:Benzoates; D005520:Food Preservatives; D019817:Benzoic Acid; D013011:Sorbic Acid