Abstract

Baird-Parker agar with egg yolk/tellurite emulsion (BPA) is widely accepted as a medium for the enumeration of Staphylococcus aureus in foods. However, it is not completely selective and colonies of other genera or species could be similar to those of Staphylococcus aureus. Moreover, the strains of Staphylococcus aureus that are lecithinase negative could go unnoticed. Both facts could affect the counts. The aim of this study was to determine whether the enumeration of the colonies with the typical morphology of Staphylococcus aureus on BPA is sufficient to quantify this species in poultry meat. Forty chicken carcasses were tested for Staphylococcus aureus by surface plating using BPA. Results indicate that the predictive value of the morphology of the colonies on BPA is 85.71% and 68.42% for typical and atypical colonies of Staphylococcus aureus, respectively. However, Staphylococcus aureus counts (after identification) and counts of typical colonies did not show any significant differences (P>0.05) and are significantly (P<0.001) correlated (r = 0.996). These results suggest that, for screening purposes, enumeration of Staphylococcus aureus from poultry meat does not require any identification of strains, resulting in a saving of time and money.

• Keywords: Staphylococcus aureus; poultry; Baird-Parker; screening test