Thermal Inactivation Parameters of Salmonella in Lipid-Based Nutrient Supplements (LNS)

Thermal inactivation of Salmonella enterica (8-strain cocktail) was evaluated in three lipid-based nutrient supplement (LNS) formulations: peanut-based (PB), chickpea-based (CP), and a high-fat/high-sugar worst-case (WC) matrix made using the PB product. Inoculated samples were treated isothermally from 87 to 115°C, and kinetic parameters for Salmonella inactivation were determined. Across products, inactivation followed a log-linear behavior with high model fits (R² >0.90). Significant differences in temperature sensitivity were observed: CP exhibited the highest z-value (22.1°C), followed by the WC (19.2°C) and PB (17.8°C). Pairwise analysis confirmed that CP and PB differed significantly in z-value (p < 0.05), indicating that incremental temperature increases are less effective in the CP formulation when compared to PB. These results highlight that thermal resistance of Salmonella in these three LNS is not only high, but also formulation-dependent, and that processing conditions validated in one LNS type cannot be generalized to others. In humanitarian nutrition contexts where products are consumed by immunologically vulnerable populations, process design should consistently target a validated ≥ 5-log reduction of Salmonella to provide an adequate safety margin. This study provides product-specific kinetic data and underscores the need for independent validation of lethality steps in different LNS formulations.