Greek functional Feta cheese: Enhancing quality and safety using a Lactobacillus plantarum strain with probiotic potential

The aim of the study was to investigate the performance of Lactobacillus plantarum T571 with probiotic potential as a co-starter culture in Feta cheese production and in its long-term storage. For this reason, Feta cheese was manufactured without (control) or with the probiotic T571 strain (probiotic) and then monitored during storage at 4 and 12 °C, respectively. The products were also inoculated with Listeria monocytogenes (3-strain cocktail). The results showed that lactic acid bacteria exceeded 6 log CFU/g during storage in all trials. The probiotic samples displayed higher acidity (≈1.5% lactic acid) and lower pH (≈4.2). Coliforms and L. monocytogenes, were inactivated in shorter time in probiotic samples, in comparison with the control ones. Pulsed field gel electrophoresis verified the presence of the probiotic strain in the cheese, until the end of storage at both temperatures, whilst the survival and distribution of the pathogenic strains depended on the trial. The sensory evaluation showed that the probiotic cheeses had desirable sensory characteristics similar to the control ones, with scores of ca. 8 on a 10 cm-scale. Finally, Fourier transform infrared spectroscopy was applied for the first time during Feta cheese storage with promising results for the rapid estimation of the microbiological counts and sensory status of cheese. Results showed that Lb. plantarum T571 highlighted desirable and robust technological properties and may be used in cheese making as an adjunct culture.