Impact of carrier agents and temperature during storage of dry inocula of Salmonella enterica: a contribution to the validation of low water activity foods processing interventions

Abstract

In this study, dry inocula were developed using four different carriers [talc, fine sand (0.05–0.2 mm), regular sand (0.2–0.6 mm), and calcium carbonate] for validation of inactivation steps of low moisture foods against Salmonella enterica. Besides, the changes in aw and the survival of S. enterica in the dry inocula made with the four carriers were evaluated throughout the storage period of up to 150–180 days at 4 and 25 °C. Among the carriers evaluated fine and regular sand seem to constitute the best carrier agents for longer preservation of S. enterica cells to be employed in dry inocula. Besides, the storage of inoculated carrier agents under refrigeration (4 °C) enhanced the stability of the dry inocula prepared, maintaining S. enterica counts unaltered for ~ six months (p < 0.05). Overall, based on the results, it has been found that the aw variation during storage did not directly influence S. enterica survival in the dry inocula. However, considering only the aw of the dry inocula obtained using the different carrier agents, it is possible to propose combinations between carrier agents and aw of low moisture foods (LMF). The findings of this study will be highly relevant for the development of stable dry inocula for use in the validation of the inactivation steps of LMF.