Heat treatment design for the valorization of sheep cheese whey in artisanal production

Abstract

We evaluated the thermal death (62-85 ºC) of the native microbial load in sheep cheese whey (SCW), aiming to allow its use as an ingredient in smallholdings. The results showed a microbiota with mixed thermal resistance and its inactivation kinetic was fitted to a biphasic first-order kinetic model. D-values were 60.8-1.2 min at 62-70 °C (sensitive population) and 35.4-14.1 min at 70-75 ºC (resistant population). In addition, a thermoduric population (~1 log CFU/mL) was not inactivated up to 85 ºC/ 30 min. We selected three binomials (68, 75, and 80 ºC for 20, 6, and 1 min, respectively) to study the microbial growth and the physical and physicochemical changes of SCW during storage (7 ºC/ 21 days). The results demonstrated that a binomial temperature of 75 °C/ 6 min was the best option for SCW stabilization, guaranteeing acceptable microbial counts up to 14 days of storage and preserving its physical and physicochemical characteristics. These results are fundamental to guide the processing conditions of this by-product in smallholdings and can be directly applied by researchers and sheep cheese producers.