The Effect of Thymus serpyllum L. and Its Preparations on Reduction of L. monocytogenes and S. aureus in Kombucha Fresh Cheese

Fresh cheese is characterized by a limited shelf life, which represents a major challenge in its production. Wild thyme (Thymus serpyllum L.) has an antimicrobial capacity demonstrated in numerous studies. The utilisation of its by-product obtained in the production of filter tea could improve fresh cheese technology by obtaining a product with additional functional value and protecting the environment by reducing industrial waste. Our study sought to explore how incorporating wild thyme, in the form of dry extract, supercritical fluid extract, and herbal ground, affects the microbiological composition of fresh cheese made with kombucha inoculum as the starter culture over a 30-day storage period. To assess antimicrobial efficacy, we deliberately exposed the samples we produced to common foodborne pathogens, namely Listeria monocytogenes and Staphylococcus aureus. The results showed that the total number of L. monocytogenes and S. aureus in each sample (produced with dry extract, supercritical fluid extract, and herbal ground) decreased significantly during the storage period. The decrease in L. monocytogenes count varied from 0.6 to 1.7 log CFU/g. The results suggest that a by-product from the production of wild thyme filter tea is suitable for the production of fresh cheese to improve its antimicrobial properties against L. monocytogenes and S. aureus.