Effect of Desiccation on Tolerance of Salmonella enterica to Multiple Stresses

Abstract

Reducing the available water in food is a long-established method for controlling bacterial growth in the food industry. Nevertheless, food-borne outbreaks of salmonellosis due to consumption of dry foods have been continuously reported. Previous studies showed that dried Salmonella cells acquire high tolerance to heat and ethanol. In order to examine if dehydration also induces tolerance to other stressors, dried Salmonella enterica serotype Typhimurium cells were exposed to multiple stresses, and their viability was assessed. Indeed, desiccated S. Typhimurium acquired higher tolerance to multiple stressors than nondesiccated cells. The dried cells were significantly more resistant to most stressors, including ethanol (10 to 30%, 5 min), sodium hypochlorite (10 to 100 ppm, 10 min), didecyl dimethyl ammonium chloride (0.05 to 0.25%, 5 min), hydrogen peroxide (0.5 to 2.0%, 30 min), NaCl (0.1 to 1 M, 2 h), bile salts (1 to 10%, 2 h), dry heat (100°C, 1 h), and UV irradiation (125 W/cm 2 , 25 min). In contrast, exposure of Salmonella to acetic and citric acids reduced the survival of the dried cells (1.5 log) compared to that of nondesiccated cells (0.5 log). Three other S. enterica serotypes, S. Enteritidis, S. Newport, and S. Infantis, had similar stress responses as S. Typhimurium, while S. Hadar was much more susceptible and gained tolerance to only a few stressors. Our findings indicate that dehydration induces cross-tolerance to multiple stresses in S. enterica, demonstrating the limitations of current chemical and physical treatments utilized by the food industry to inactivate food-borne pathogens.

Impact of Acanthamoeba Cysts on Stress Resistance of Salmonella enterica Serovar Typhimurium, Yersinia enterocolitica 4/O:3, Listeria monocytogenes 1/2a, and Escherichia coli O:26

“…However, bacteria, including foodborne pathogens, have evolved complex interacting systems to tolerate desiccation and osmotic stresses (29,30). Gruzdev proved that desiccated Salmonella acquired higher tolerance to subsequent ethanol, hypochlorite, hydrogen peroxide, and NaCl treatments (29). This is in accordance with the results obtained in the present study.…”

“…The intracystic environment can be considered a stressful condition for intracystic organisms, as cysts dehydrate and expel nutrients during encystment (2). However, bacteria, including foodborne pathogens, have evolved complex interacting systems to tolerate desiccation and osmotic stresses (29,30). Gruzdev proved that desiccated Salmonella acquired higher tolerance to subsequent ethanol, hypochlorite, hydrogen peroxide, and NaCl treatments (29).…”

Contamination Des Eaux De Puits Par Les Salmonelles Et Les Vibrions non-O1/non-O139 Dans Les Quartiers Précaires Du Sixième Arrondissement De Cotonou (Sud-Bénin)

“…Ces derniers sont dits « viables mais non cultivables » (Gruzdev et al, 2011). La perte de culture est le résultat de divers stress (stress nutritionnel, thermique, lumineux) que subissent les bactéries fécales lorsqu'elles sont rejetées dans un milieu aquatique naturel (Roszak et Colwell, 1987 ;Gruzdev et al, 2011). Il est à noter que, ces bactéries viables non cultivables peuvent conserver leur pathogénicité (Habimana et al, 2014).…”

Microbial ecology of fresh vegetables

“…The desiccation tolerance of several different serovars demonstrated a range of survival from 36 to 80%, depending on the serovar. Additionally, exposing salmonellae to desicca tion conditions induced tolerance to several other stressors, including high salts, ethanol, bleach, high temperatures, and UV irradiation (Gruzdev et al, 2011).…”