The influence of temperature and water activity on thermal resistance of Salmonella in milk chocolate

Salmonella contamination of chocolate-derived products has caused several outbreaks and recalls in recent years. Earlier research found that reducing moisture content or water activity low-moisture foods sharply enhances the resistance during thermal treatments. However, there is a lack data correlates relationship between temperature, (aw), milk chocolate. In this study, chocolate was inoculated with Enteritidis PT 30 conditioned to aw 0.23, 0.33, 0.43 at room temperature (21 ± 2 °C). The samples were heated 70, 75, 80 °C obtain D-values (time inactivate 90% test microorganisms given temperature) S. 30. change chocolates elevated temperatures (up °C) also investigated. results showed D-value decreased exponentially increase temperature. maximum 47.4 3.7 min obtained 70 0.23. minimum 5.2 1.0 0.43. z-values as followings: zaw, 70°C = 0.42, 75°C 0.36, 80°C 0.46 °C; zT, 0.23 18.8 2.5, 0.33 20.6 4.1, 18.1 0.5 °C. Overall, from may provide useful information help industry control risk improve microbial safety production.