Low molecular weight milk whey components protect Salmonella senftenberg 775W against heat by a mechanism involving divalent cations

Aims: To investigate which components of milk increase the heat resistance of Salmonella senftenberg 775W, and to explore the mechanisms that could be involved in this protective effect. Methods and Results: The heat resistance of Salm. senftenberg was determine d in a specially designed resistometer in several heating media. The molecu les responsible for the thermal protective effect of milk were in the prote in fraction, even in the < 3000 Da ultrafiltrate. The protective effect was lost when whey was demineralized. The former protective effect was restore d when calcium or magnesium was added. Milk components protected cell envel opes of Salm. senftenberg from heat damage. Conclusions: The protein fraction and divalent cations were responsible for the protective effect of milk. The whole protective effect on Salm. senfte nberg was not the result of the addition of the protective effect of each c omponent, but the result of a synergistic effect of some of them interactin g. Significance and Impact of the Study: This work could be useful for improvi ng food preservation and hygiene treatments, It also contributes to our kno wledge of microbial physiology.