Effect of Milk Preservation Treatments on the Ripening Quality of Saint-Paulin Cheese

Saint-Paulin type cheese was produced using cow’s milk stored at 4 °C for 72 hours, treated with a combination of lactoperoxidase (LP) system activation and thermal processes (55 °C for 15 seconds and 72 °C for 15 seconds). This study assessed the impact of these combined treatments on the physicochemical, microbiological, and biochemical characteristics of the cheese during a 23-day ripening period. Three milk variants were used: untreated control (C0), LP-inactivated refrigerated milk (C1), and LP-activated refrigerated milk (LP). Among the samples, the LP-activated treatment showed the lowest microbial contamination. Cheese derived from milk treated at 55 °C following LP activation (P55a) exhibited similar quality to that treated at 72 °C without LP activation (P72). The LP-treated cheeses had significantly reduced levels of coliforms, yeasts, and molds (P < 0.05), highlighting the antimicrobial effect of the LP system. Lipolysis levels remained comparable across samples. However, proteolysis was reduced by approximately 20% in LP-activated cheeses under the same heat conditions. Proteolysis indices for P72 and P55a cheeses were notably close. These findings were corroborated through azocasein analysis, which monitored variations in soluble nitrogen and non-protein nitrogen absorbance during ripening in all four cheese types.