[Recovery of Staphylococcus aureus after acid injury in milk products].
The growth behavior of Staphylococcus aureus in fresh Cheese (Minas and Muzzarella) during their shelf-life was studied. The possible injury of this microorganism caused by the increasing acidity was also investigated. Raw milk was inoculated with 10(6) cells/ml (S. aureus FRIA-100) and the cheese production was performed according to normal procedures. Minas and muzzarella cheese were stored at 7 degrees C for 40 and 60 days, respectively. At 2-3 days intervals, the following analysis were performed: acidity, pH, S. aureus counting using agar Baird Parker by the traditional methods and by the method recommended by the American Public Health Association to evaluate the reparation of injured cells. We had a secure indication of the presence of injured S. aureus when acidity was in the range of 0.7 to 0.8% expressed in lactic acid and when the cycle was 1.3 log higher than the traditional one.
Assis
E M
EM
Faculdade de Engenharia de Alimentos, Departamento de Tecnología, Universidade Estadual de Campinas, Brasil.
De Carvalho
E P
EP
Asquieri
E R
ER
Robbs
P G
PG
D000818:Animals; D002417:Cattle; D002611:Cheese / Q000382:microbiology*; D005519:Food Preservation; D006863:Hydrogen-Ion Concentration; D013202:Staphylococcal Food Poisoning / Q000517:prevention & control; D013211:Staphylococcus aureus / Q000254:growth & development / Q000302:isolation & purification*; D015014:Yogurt / Q000382:microbiology*
Recuperación de Staphylococcus aureus después de la injuria ácida en productos lácteos.