Document Detail

Heat tolerance of Salmonella enterica serovars Agona, Enteritidis, and Typhimurium in peanut butter.
MedLine Citation:
PMID:  17133812     Owner:  NLM     Status:  MEDLINE    
Recent large foodborne outbreaks caused by Salmonella enterica serovars have been associated with consumption of foods with high fat content and reduced water activity, even though their ingredients usually undergo pasteurization. The present study was focused on the heat tolerance of Salmonella enterica serovars Agona, Enteritidis, and Typhimurium in peanut butter. The Salmonella serovars in the peanut butter were resistant to heat, and even at a temperature as high as 90 degrees C only 3.2-log reduction in CFU was observed. The obtained thermal inactivation curves were upwardly concave, indicating rapid death at the beginning (10 min) followed by lower death rates and an asymptotic tail. The curves fitted the nonlinear Weibull model with beta parameters < 1, indicating that the remaining cells have a lower probability of dying. beta at 70 degrees C (0.40 +/- 0.04) was significantly lower than beta at 80 degrees C (0.73 +/- 0.19) and 90 degrees C (0.69 +/- 0.17). Very little decrease in the viable population (less than 2-log decrease) was noted in cultures that were exposed to a second thermal treatment. Peanut butter is a highly concentrated colloidal suspension of lipid and water in a peanut meal phase. We hypothesized that differences in the local environments of the bacteria, with respect to fat content or water activity, explained the observed distribution and high portion of surviving cells (0.1%, independent of the initial cell number). These results demonstrate that thermal treatments are inadequate to consistently destroy Salmonella in highly contaminated peanut butter and that the pasteurization process cannot be improved significantly by longer treatment or higher temperatures.
Dina Shachar; Sima Yaron
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Journal of food protection     Volume:  69     ISSN:  0362-028X     ISO Abbreviation:  J. Food Prot.     Publication Date:  2006 Nov 
Date Detail:
Created Date:  2006-11-30     Completed Date:  2006-12-19     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  7703944     Medline TA:  J Food Prot     Country:  United States    
Other Details:
Languages:  eng     Pagination:  2687-91     Citation Subset:  IM    
Department of Biotechnology and Food Engineering, Technion, Haifa, Israel.
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MeSH Terms
Arachis hypogaea / microbiology*
Colony Count, Microbial
Consumer Product Safety
Food Contamination / analysis*,  prevention & control
Food Handling / methods*
Food Microbiology
Hot Temperature*
Models, Biological
Salmonella / growth & development*
Salmonella enterica / growth & development
Salmonella enteritidis / growth & development
Salmonella typhimurium / growth & development

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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