Fate of Staphylococcus aureus in Cheese Treated by Ultrahigh Pressure Homogenization and High Hydrostatic Pressure

Flow chart showing the procedure for the production of the different series of cheeses made with milk treated with ultrahigh pressure (UHPH) and UHPH + high hydrostatic pressure (HHP).

Counts of Staphylococcus aureus CECT 976 (expressed as means of 3 replications±confidence interval) in milk before and after ultrahigh pressure homogenizing treatment of 330MPa (first valve) and 30MPa (second valve), at inlet temperatures of 6 and 20°C. No = initial counts of Staph. aureus in milk samples; N = counts of Staph. aureus in the same milk after ultrahigh pressure homogenizing treatment. Different letters above bars indicate significant difference among the means (P<0.05).

Evolution of counts of Staphylococcus aureus CECT 976 (expressed as means of 3 replications±confidence interval) in control cheeses (♦), ultrahigh pressure homogenization (UHPH) cheeses (▴), and in UHPH + high hydrostatic pressure cheeses (●) stored at 8°C. A) Counts at UHPH inlet temperature of 6°C; B) Counts at UHPH inlet temperature of 20°C. When interval bars are not visible they fall within plot symbols.