If you are experiencing problems downloading PDF or HTML fulltext, our helpdesk recommend clearing your browser cache and trying again. If you need help in clearing your cache, please click here . Still need help? Email email@example.com
The influence of growth temperature on heat- , lactic acid- , and freeze-induced inactivation and injury of Escherichia coli O157:H7 in 0.1% peptone water was investigated. Three strains of E. coli O157:H7 isolated respectively from salami, apple cider, and ground beef
were evaluated. Growth of strains at 10°C compared with growth at 37°C had a significant impact on reducing (P < 0.01) D values obtained for heating (DH value), acid exposure (DA value), and freezing (DF value),
with the exception of the cider strain stored in lactic acid solutions. When strains were cultivated at 10 and 37°C and heated at 54 and 56°C, the salami strain possessed the highest (P < 0.01) DH values (5.9 to 59.7 min). When grown at 10°C, the beef
strain had the lowest (P < 0.0 1) DH values after heating at 52, 54, and 56°C (11.2, 4.1, and 2.5 min, respectively). The salami strain grown at 10°C had the highest (P < 0.01) DA values in all concentrations of lactic acid. When
grown at 37°C, the salami strain had the highest (P < 0.01) DA values after storage in 0.1 and 0.25% lactic acid, while DA values for the salami and beef strains did not differ (P > 0.05) when stored in 0.5% lactic acid. Portions
of strain populations were sublethally injured by heat and lactic acid treatments, as evidenced by the inability of injured organisms to form colonies on tryptone soya agar containing 2% NaCl. Strains cultured at 10°C were more susceptible to sublethal heat injury than strains cultured
at 37°C. Storage of test strains at −20°C for 7 months resulted in a 4- to 6-1og CFU/ml reduction in viable population, but induced only minimal sublethal injury. After 5 months at −20°C, strains cultured at 10°C were more sensitive to freeze inactivation than strains
cultured at 37°C. When grown at 10 and 37°e and stored at −20°C for 7 months, the cider strain possessed higher (P < 0.01) DF values than the beef and salami strains.
Document Type: Research Article
The University of Tennessee Agricultural Experiment Station, Department of Food Science and Technology, P.O. Box 1071, Knoxville, Tennessee 37901-1071, USA
Publication date: April 1, 1998
More about this publication?
IAFP members must first sign in on the right to access full text articles of JFP First published in 1937, the Journal of Food Protection®, is a refereed monthly publication. Each issue contains scientific research and authoritative review articles reporting on a variety of topics in food science pertaining to food safety and quality. The Journal is internationally recognized as the leading publication in the field of food microbiology with a readership exceeding 11,000 scientists from 70 countries. The Journal of Food Protection® is indexed in Index Medicus, Current Contents, BIOSIS, PubMed, Medline, and many others.
Print and online subscriptions are available to Members and Institutional subscribers. Online visitors who are not IAFP Members or journal subscribers will be charged on a pay-per-view basis. Information can be obtained by calling +1 800.369.6337; +1 515.276.3344; fax: +1 515.276.8655, E-mail: firstname.lastname@example.org or Web site: www.foodprotection.org