Mathematical Modeling of Salmonella Multiplication in Mayonnaise

The Salmonella Enteritidis SE86 strain has been identified as the main cause of salmonellosis in Rio Grande do Sul and the main food involved has been homemade mayonnaise (HM). Thus this study aimed to model the multiplication of SE86 in HM and study the practices of preparation storage and consumption of HM in RS. SE86 was inoculated into HM and stored at 7 10 15 20 25 30 and 37°C. Multiplication curves were constructed using Baranyi's DMFit generating R² values greater than 0.98 for the primary models. The secondary model was performed using Ratkowsky's equation obtaining R² and RMSE values of 0.99 and 0.016 respectively. The experimental data showed that SE86 did not multiply in MC at 7°C for 30 days while at 37°C it reached the infecting dose (10E6 CFU/g) in 6 h and the final population (10E9 CFU/g) in 13 h. The lag phases of SE86 in MC were shorter than those simulated in the tertiary models suggesting that SE86 adapts quickly to this food. In addition the questionnaire that evaluated the practices adopted by consumers and MC handlers showed that most respondents had a low level of IPShp.