Efficacy of ozonation on microbial counts in used brines for cheesemaking

Due to their prolonged use, cheese brines are progressively enriched with organic substances, which allows microorganisms arising from the curds to achieve high concentrations. In this study, the feasibility of using gaseous ozone to reduce the microbial contamination of used brines was evaluated. The antimicrobial effect of ozone increases with the concentration and treatment time, reducing the total bacterial counts by 4.61 log cfu mL−1, the microstaphylococci counts by 3.37 log cfu mL−1 and the yeast counts by 2.70 log cfu mL−1, in the case of the stronger treatments. The antimicrobial effect of ozone was influenced by the protein content of brines. However, in brines that contain high amounts of protein, the inactivation effect of ozone was still significant. The Weibull model accurately estimated both the inactivation and the concavity exhibited in the survival curves for treatments at a concentration of 0.40 mg L−1 of ozone for 240 min.