The objective was to determine the effect of cider composition on the heat resistance of Escherichia coli O157:H7. The average D-52 value in a model Empire apple juice was 18 min with a z value of 4.8 degrees C. Increasing the Brix from 11.8 to 16.5 degrees had no effect on thermal resistance, while increasing L-malic acid from 0.2 to 0.8%, or reducing the pH from 4.4 to 3.6 sensitized the cells to heat. The greatest effect on heat resistance was afforded by the preservatives benzoic and sorbic acids: D-50 values in ciders containing 1,000 mg/l were 5.2 min in the presence of sorbic acid and only 0.64 min in the presence of benzoic acid. Commercial apple juice concentrates yielded lower numbers of survivors than single-strength juices even though their higher sugar concentrations of about 46 degrees Brix increased heat resistance.
机构:
Ho Chi Minh City Univ Technol, Dept Biotechnol, Fac Chem Engn, Ho Chi Minh city, VietnamHo Chi Minh City Univ Technol, Dept Biotechnol, Fac Chem Engn, Ho Chi Minh city, Vietnam
Hoang, Hoang A.
Dien, Le T.
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机构:
Ho Chi Minh City Univ Technol, Dept Biotechnol, Fac Chem Engn, Ho Chi Minh city, VietnamHo Chi Minh City Univ Technol, Dept Biotechnol, Fac Chem Engn, Ho Chi Minh city, Vietnam