Survival of Salmonella Montevideo on red chili (Capsicum annuum L.) during microwave drying as influenced by...

Dried chilies, although widely used as food ingredients such as paprika, present food safety risks across the production chain due to bacterial contamination, including Salmonella. This study assesses the fate of Salmonella Montevideo on red peppers during microwave drying and compares predictive models incorporating the effects of dynamic temperature and water activity (a_w). Fresh red chilies (a_w = 0.98) were sliced lengthwise, inoculated with Salmonella Montevideo, then dried at two power levels in a microwave oven for 45 min (120W) and 18 min (240W) to achieve a_w<0.60. Temperature dynamics (24.5-87.6°C) were captured using an infrared camera, then the a_w and Salmonella counts were measured at each sampling point. Salmonella survival parameters were estimated with four primary models (Weibull, log-linear, Geeraerd, and Cerf models), and then the Bigelow-type model was incorporated into the selected primary model to characterize the effects of temperature and a_w on Salmonella inactivation. All models were assessed using the corrected Akaike information criterion (AIC_c). Higher microwave power resulted in lower Salmonella survival over time (p < 0.05) with a reduction range of 2.3-3.2 log. The log-linear/Bigelow (z_T) yielded the lowest AIC_c value (11.94), which was the best-fitted model with D_77°C-value of 4.24 min and a z_T-value of 9.15°C. Temperature changes are determinant to describe Salmonella survival during chili drying, as the log-linear/Bigelow (z_T) model better described the nonlinear reduction of Salmonella during the process. These findings serve as a basis to develop and refine spice drying conditions to improve Salmonella control while maintaining quality.