The food hygiene aspects of the Sous-vide, as a mild heat treatment technology
Keywords:
Listeria, Staphylococcus, Zygosaccharomyces, thermal deathAbstract
Due to the world population growth, human food supply and even the feeding faced a peculiar dichotomy: producing and processing the more food and feed material (biomass) per unit area in such a way as to have favorable nutritional indicators to consumers. To accomplish this, there is a great opportunity called sous-vide (French word for ’under vacuum’) technology, which is classified as a gentle heat treatment. In they researches, they heat treated artificially preserved food matrixes (minced pork and vegetable mix) which were packed under vacuum and atmospheric pressure (control) modelling this gentle heat treatment. They determined the effects of heat treatments with different temperatures (50-65 °C) and holding times (10-40 minutes) on the mortality parameters (k-value, D-value, z-value) of species like Staphylococcus aureus, Listeria monocytogenes, and Zygosaccharomyces bailii. The mortality curves were based on the number of surviving cells during heat treatments. To detect them, classical microbiological methods were used. According to they results, a significant difference in the number of surviving cells was experienced on 55 to 60 °C holding time in meat matrix. This occurred in the case of samples inoculated by Listeria monocytogenes NCAIM B.01373T strains and the control samples as well. Heat holding results of Staphylococcus aureus ATCC 25923 strain showed a significant difference in meat matrix (on three temperatures: 55, 60 and 65 °C). As for the number of surviving cells, heat treatment of samples inoculated by Zygosaccharomyces bailii NCAIM Y.00954T type strain resulted a significant difference in vegetable mix on all three heat holding temperatures (50, 55 and 60 °C). In accordance with the sous vide principles, they defined the minimum heat treatment parameters with which the number of the test species, considering the 6D principle, can be reduced to a safe level. This ensures the microbiological stability of the products.
