IngentaConnect Inactivation Kinetics of Three Listeria monocytogenes Strains und...

Authors: Van Boeijen, Ineke K.H.¹; Moezelaar, Roy²; Abee, Tjakko³; Zwietering, Marcel H.⁴

Source: Journal of Food Protection®, Volume 71, Number 10, October 2008 , pp. 2007-2013(7)

Publisher: International Association for Food Protection

Abstract:

High hydrostatic pressure (HHP) inactivation of three Listeria monocytogenes strains (EGDe, LO28, and Scott A) subjected to 350 MPa at 20°C in ACES buffer resulted in survival curves with significant tailing for all three strains. A biphasic linear model could be fitted to the inactivation data, indicating the presence of an HHP-sensitive and an HHP-resistant fraction, which both showed inactivation according to first-order kinetics. Inactivation parameters of these subpopulations of the three strains were quantified in detail. EGDe showed the highest D-values for the sensitive and resistant fraction, whereas LO28 and Scott A showed lower HHP resistance for both fractions. Survivors isolated from the tail of LO28 and EGDe were analyzed, and it was revealed that the higher resistance of LO28 was a stable feature for 24% (24 of 102) of the resistant fraction. These HHP-resistant variants were 10 to 600,000 times more resistant than wild type when exposed to 350 MPa at 20°C for 20 min. Contrary to these results, no stable HHP-resistant isolates were found for EGDe (0 of 102). The possible effect of HHP survival capacity of stress-resistant genotypic and phenotypic variants of L. monocytogenes on the safety of HHP-processed foods is discussed.

Document Type: Research article

Affiliations: 1: Top Institute for Food and Nutrition (TIFN), P.O. Box 557, 6700 AN Wageningen, The Netherlands; Wageningen University and Research Centre, Laboratory of Food Microbiology, P.O. Box 8129, 6700 EV Wageningen, The Netherlands; Wageningen University 2: Top Institute for Food and Nutrition (TIFN), P.O. Box 557, 6700 AN Wageningen, The Netherlands; Wageningen University and Research Centre, Food Technology Centre, P.O. Box 17, 6700 AA Wageningen, The Netherlands 3: Top Institute for Food and Nutrition (TIFN), P.O. Box 557, 6700 AN Wageningen, The Netherlands; Wageningen University and Research Centre, Laboratory of Food Microbiology, P.O. Box 8129, 6700 EV Wageningen, The Netherlands 4: Wageningen University and Research Centre, Laboratory of Food Microbiology, P.O. Box 8129, 6700 EV Wageningen, The Netherlands

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Inactivation Kinetics of Three Listeria monocytogenes Strains under High Hydrostatic Pressure