THERMAL RESISTANCE OF YERSINIA ENTEROCOLITICA AND LISTERIA MONOCYTOGENES IN MEAT AND POTATO SUBSTRATES |
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| Authors: | ALICE M. DOHERTY CAROL. M.M. McMAHON J.J. SHERIDAN I.S. BLAIR D.A. McDOWELL T. HEGARTY |
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| Affiliation: | The National Food Centre Teagasc, Dunsinea Castleknock Dublin 15, Ireland;University of Ulster at Jordanstown Co Antrim BT37 OQB Northern Ireland;Teagasc, Statistics Department 19 Sandymount Avenue Dublin 4, Ireland |
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| Abstract: | The heat resistance of a wild type and nalidixic acid resistant strain of Yersinia enterocolitica, and Listeria monocytogenes, was measured in meat (minced beef and minced beef homogenate) and potato substrates over the temperature range 50–60C. Comparisons of heat resistance were determined using D-values calculated using a linear survival model. The results showed that the wild-type strain of Y. enterocolitica was more heat resistant than the mutant (p<0.05). Under most conditions, the use of a nonselective/overlay recovery medium resulted in higher D-values compared to a selective recovery medium (p<0.05). Analysis of the data using a nonlinear survival model (D1 and D2 -values) suggested the presence of heat resistant subpopulations and was particularly evident for the mutant strain, and in potatoes compared to minced beef. |
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