Magalhães, RuiFerreira, VâniaBrandão, Teresa R. S.Casquete Palencia, R.Almeida, GonçaloTeixeira, Paula2017-10-122017-10-122016MAGALHÃES, 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. 103-108http://hdl.handle.net/10400.14/22993This 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.engListeria monocytogenesPersistentGrowthMicrotiter plate assayStressTemperatureSanitizersHydrogen peroxideQuaternary ammonium compoundsjournal article10.1016/j.fm.2016.02.005WOS:000373573100014