Thermal inactivation of Salmonella in chicken curry puff filling

Abstract

This study explores the potential risk of Salmonella contamination in chicken curry puff filling, focusing on chicken as a high-risk ingredient during filling preparation. It investigates cooking temperature as a critical control point to reduce Salmonella contamination and determines thermal inactivation kinetic parameters (D- and z-values) in chicken curry puff filling. The pH, water activity, and proximate composition of the filling were analysed. Ground chicken was inoculated with a target concentration of approximately 7 log cfu/g of Salmonella and its survival was assessed at pre-determined internal temperatures (60, 67, 74, and 81 ℃) using thin-layer agar plating. The Salmonella concentration decreased below the enumeration limit (1 log CFU/g) after 25.5 min at an internal temperature of 74°C, demonstrating a significant reduction. However, complete elimination was not confirmed in this study, suggesting potential for further investigation. Thermal inactivation parameters were determined at 55, 57.5, 60, and 62.5°C using temperature-controlled water baths. The D-values were 29.31 ± 0.42, 7.26 ± 0.29, 5.45 ± 0.42, and 1.34 ± 0.05 min at 55, 57.5, 60, and 62.5°C, respectively, with a z-value of 6.03°C. These parameters can be used to predict the time and temperature to achieve a 7-log cfu/g reduction of Salmonella, aligning with the current performance standard in commercial poultry processing. These findings provide essential data for food manufacturers to develop HACCP plans aimed at effectively reducing Salmonella in chicken curry puff filling and related products.