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Advisor(s)
Abstract(s)
This study aimed to investigate the effect of different conditions, including temperature (37 C, 22 C, and
4 C), NaCl concentrations (2.5%, 4%, and 8%), and acidity (pH ¼ 5), on the growth response of persistent
and non-persistent isolates of Listeria monocytogenes. The resistance to two common sanitizers (benzalkonium
chloride and hydrogen peroxide) was also investigated. A selected group of 41 persistent and
non-persistent L. monocytogenes isolates recovered from three cheese processing plants during a previous
longitudinal study was assembled. Average lag time was similar for persistent and non-persistent
isolates grown at 37 C, 22 C and 4 C but significantly shorter (p < 0.05) for persistent isolates grown at
2.5%, 4% and 8% NaCl, and at pH 5. Average growth rates were significantly higher (p < 0.05) for persistent
than for non-persistent isolates when grown at 22C, 2.5%, 4% and 8% NaCl, and at pH 5. These results
suggest that persistent strains may be better adapted to grow under stressful conditions frequently
encountered in food processing environments than non-persistent strains. No relation between persistence
and resistance to the tested sanitizers was found.
Description
Keywords
Listeria monocytogenes Persistent Growth Microtiter plate assay Stress Temperature Sanitizers Hydrogen peroxide Quaternary ammonium compounds
Citation
MAGALHÃES, Rui; FERREIRA, Vânia; BRANDÃO, Teresa R. S.; CASQUETE Palencia, R.; ALMEIDA, Gonçalo; TEIXEIRA, Paula - Persistent and non-persistent strains of listeria monocytogenes: A focus on growth kinetics under different temperature, salt, and pH conditions and their sensitivity to sanitizers. Food Microbiology. ISSN 0740-0020. Vol. 57 (2016), p. 103-108
Publisher
Elsevier