Survival, Elongation, and Elevated Tolerance of Salmanella enterica Serovar Enteritidis at Reduced Water Activity

Abstract

Growing microorganisms on dry surl'aces. which results in exposure to lorv water activity (a*), may change their nolmal nrorphology and physiological activity. In this study, the morphological chanses and cell viabiiity of Salmonella etierica serovar Enteritidis challenged to low ao. were analyzed. The results indicated that exposure to reduced a* induced filamentation of the cells. The amount of filamentous ceils at a*, 0.94 was up to 9OVc of the total number of cells. Surviving filamentous cells maintained their membrane integrily afier exposure to lor.v ao. for 21 days. Furthermore, cells prechallenged to low a*,, obtained with an ionic humectant. demonstrated higher resislance to sodium hypochlorite than control cells. These resistant cells are able to survive disinl'ection more efhciently and can therefore cause contamination ol foods coming in contact u,ith surfaccs. This points to the need ibr incrcased attention to cleaning of surlaces in household environments and disinfection procedures in processing plants.