Salmonella enterica inactivation in an almond-based pastry: pink macarons

Low water activity (aw) bakery products represent a challenging substrate for pathogen control, supporting Salmonella enterica survival rather than growth, making baking a critical control point for product safety. Therefore, thermal treatment validation is essential for ensuring process reliability and food safety. This study determined the industrial baking process effectiveness to control a cocktail of S. enterica strains inoculated in pink macarons, selected as a worst-case scenario kill-step validation in low-aw bakery products. In the raw dough, lactic acid bacteria were the dominant microbial population (6.69 ± 0.27 Log CFU/g), while the absence of Enterobacteriaceae, Bacillus spp., and Staphylococcus spp. Confirmed the good hygiene practices applied during the production. Heat penetration curves revealed core temperatures (131.6 °C) higher than those required for Salmonella inactivation in similar bakery products. The challenge test demonstrated a 5-Log reduction of S. enterica , validating the kill-step. The thermal resistance parameters (D- and z-values) provided specific reference data for pink macarons: D-values were 19.85 ± 1.30, 5.06 ± 0.70, and 1.39 ± 0.14 min at 50, 55, and 60 °C, respectively, and the z-value was 8.66 ± 0.14 °C. Hence, this study establishes pink macarons as a model to validate baking in low-aw food products, providing useful data for process optimisation and S. enterica thermal resistance.