Eight foodborne pathogens were suspended in ultrahigh-temperature whole milk and treated at pressure levels of 0.1 to 690 MPa at 21.5°C for 10 min. There was no clear trend in pressure resistance between gram-negative and gram-positive organisms. The order of the single strains
tested, from most to least pressure sensitive, was Vibrio parahaemolyticus < Yersinia enterocolitica < Listeria monocytogenes < Salmonella enterica serovar Typhimurium < S. enterica serovar Enteritidis < Escherichia coli O157:H7 ≅
Staphylococcus aureus < Shigella flexneri. For each organism there existed a pressure range in which log(number of survivors) had a near linear relationship when plotted versus treatment pressure level. In this study, a decimal reduction pressure (DP) value
was defined and used to measure the sensitivity of these pathogens to pressure changes. L. monocytogenes and V. parahaemolyticus were most sensitive to pressure changes, and S. flexneri was most resistant. The DP values were 16.3 MPa for L. monocytogenes,
21.7 MPa for V. parahaemolyticus, and 127.0 MPa for S. flexneri. The most pressure-resistant gram-negative bacterium, S. flexneri, and most pressure-resistant gram-positive bacterium, S. aureus, were treated at 50°C and pressures of 0.1 to 650 MPa for 10 min.
High temperature considerably enhanced pressure inactivation of these two organisms and affected their sensitivities to pressure changes. The effect of treatment time on the DP values of L. monocytogenes and V. parahaemolyticus was also determined, and it was
found that it did not significantly affect their DP values.
Document Type: Research Article
Department of Animal and Food Sciences, University of Delaware, Newark, Delaware 19716-2150, USA
Publication date: January 1, 2006
More about this publication?
IAFP Members with personal subscriptions to JFP Online: To access full-text JFP or JMFT articles, you must sign-in in the upper-right corner using your Ingenta sign-in details (your IAFP Member Login does not apply to this website). The Journal of Food Protection (JFP) 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 IAFP Members and institutional subscribers. IAFP Members with a subscription to JFP Online will have access to all available JFP and JMFT content. Online visitors who are not IAFP Members or journal subscribers will be charged on a pay-per-view basis. Membership and subscription information is available at www.foodprotection.org.