The influence of phenolic extract from olive vegetation water and storage temperature on the survival of Salmonella Enteritidis inoculated on mayonnaise

This study evaluated the behaviour of Salmonella Enteritidis in homemade mayonnaise added with a phenolic extract from olive vegetation water (PEOVW) and subjected to different storage conditions by using a multifactors statistical approach and kinetic models. Mayonnaise (pH =4.3, aw = 0.95) with 250 mg/kg polyphenols (PEM) and without (CM) were prepared and both inoculated with Salmonella at the final concentration of 5 Log CFU/g. Salmonella was enumerated in samples stored at 4 °C and at 22 °C for up to 48 h. In the CM mayonnaise, Salmonella population remained constant in samples stored at 4 °C (k = 0.4%/hour, P > 0.05) while it proliferated at 22 °C (k = 1.8%/hour, P < 0.01) showing an increase of 1 Log CFU/g after 48 h (P < 0.001). The bactericidal effect of phenolic extract already occurred 1 h after inoculation (P < 0.05) and Salmonella count dropped by 9.5% and 5.8% per hour at 4 °C and 22 °C, respectively (P < 0.01). After 48 h, in PEM it was no longer detectable at both storage temperatures (P < 0.001). In conclusion, S. Enteritidis survives in additivefree mayonnaise stored at 4 °C and can proliferate if it is stored at 22 °C. The addition of PEOVW is effective for Salmonella control but the death rate is higher if the mayonnaise is stored at 4 °C.