Inactivation of Salmonella Typhimurium during low heat convection drying of winged kelp (Alaria esculenta)

Processing of seaweed often includes low-temperature drying to stabilise the product by inactivation and inhibition of the growth of microorganisms due to the low water activity. Salmonella is known to resist dry conditions, persist in low-moisture food, and has been linked to foodborne outbreaks from seaweed. Yet, no information is available on the inactivation kinetics of Salmonella during the convection drying of seaweed. Here, we present experimentally obtained drying and desorption models for thawed Alaria esculenta and a model to describe the inactivation kinetics of S. Typhimurium during low heat (<40 °C) convection drying. To describe the drying process, the best-fitting drying models were Weibull (α 20.0, β 0.513) and Page (k 0.215, n 0.513). The Guggenheim-Anderson-de Boer (C 1.031, k 0.958, X0 0.265) was the best-suited desorption model. The Geeraerd inactivation model with a tail best described the inactivation kinetics of S. Typhimurium (N0 0.04, kmax −0.13, Nres −3.98). These findings can be applied to predict the rates of drying of kelp and inactivation of S. Typhimurium. With no other control measures, pre-drying contamination of the seaweed with levels of S. Typhimurium >2.6 log(CFU g−1) could present a risk due to the potential survival of the pathogen during drying.