Manchego type cheese was manufactured from milk from cows, goats and ewes artificially contaminated with 2 X 10(4) S. aureus cells ml. Lactic starter culture was added to the milk at the rate of 1.0 or 0.1% (v/v). the industrial process of Manchego type cheese manufacture was imitated. Cheeses were analyzed for both staphylococcal and non-staphylococcal total aerobic counts, as well as for the pH and enterotoxin production. Growth differences in staphylococcal counts in cheeses prepared with both starter concentrations were seen only after the brine treatment, the counts were 10 times greater with the 0.1% starter. Nevertheless, with the 1% starter culture the staphylococcal counts did not decrease from the moment of inoculation remaining high after brine treatment. For a similar inoculum, the strains used responded in a different manner, the highest values corresponding to strains FRI-100, S6 and FRI-472, and the lowest to FRI-137 and FRI-361. No differences in pH were seen between batches prepared with both starter concentrations.
Animals Cattle