Purpose: This study evaluated the effects of the addition of combined OVEO and ROEO during the manufacture of minas frescal cheese on the viability of starter mesophilic cultures Lactococcus lactis subsp. cremoris and Lactococcus lactis subsp. lactis during refrigerate storage.
Methods: After the inoculation (0.01 g/L) of starter bacteria suspension (107 CFU/mL) in pasteurized milk, OEOV and OERO combined at their Fractional Inhibitory Concentration (1/16 MIC; 0.03 μl/g + 1.32 μl/g) were added to the cheese batter. Cheese manufactured from the same bath, without oils, was prepared similarly (control). The number of viable of Lactococcus spp. cells (log CFU/mL) in the cheese was counted at 1, 3, 6, 9, 12, 15, 18, and 21 days after storage at 8-10°C by serial dilution and plating on M17 agar base. Statistical analysis considered p<0.05.
Results: Lactococcus spp. in cheese containing OVEO and ROEO exhibited similar viable cells counts (p>0.05) compared to control system over time. The initial counts in cheese manufactured with or without OVEO and ROEO was approximately 108 CFU/g. After 9 days of refrigerate storage, and increase of approximately 3 log units was observed in viable counts of Lactococcus spp. in both cheese manufactured with or without OVEO and ROEO. For both cheeses, no increase in viable counts of Lactococcus spp. was observed during the remaining assessed times.
Significance: The results showed that the application of combined OVEO and ROEO did not affect the viability of traditional starter bacteria used to produce minas frescal cheese during refrigerate storage.