Pre-Growth Environmental Stresses Affect Foodborne Pathogens Response to Subsequent Chemical Treatments.

Foodborne pathogens such as , O157:H7, and are known to survive under different environmental stresses with an effect on their physiological properties. The purpose of this study was to determine the effect of different environmental stresses on the foodborne pathogens response to subsequent chemical treatments. Three types of pathogens , O157:H7, and were subjected to different environmental stresses: (i) Desiccation (ii) high salt (iii) low pH, and (iv) temperatures (14, 23, and 37 °C) during their growth. The cells harvested at their early stationary growth phase were subsequently subjected to chlorine (100 or 200 ppm), peracetic acid (40 or 80 ppm), and 0.5% lactic acid treatments. The results showed that pre-growth stress conditions have significant effect on the reduction of tested pathogens depending upon the type of chemical treatment. showed the highest sensitivity against all these treatments when compared to O157:H7 and . In addition, showed the highest percentage of sub-lethally injured cells. These findings highlighted the need to consider pre-growth conditions as an important factor for the validation of physical and chemical intervention treatments.