This monograph has been reviewed by members of the IUMS–ICFMH Working Party on Culture Media and given ‘Approved’ status.

This is a selective medium for the enumeration of coagulase-positive staphylococci, in particular Staphylococcus aureus, in foods likely to contain Staphylococcus aureus strains which may form atypical colonies on Baird-Parker agar or in cases when high amounts of competing microorganisms are to be expected, as in cheeses made from raw milk and certain raw meat products. The egg yolk in Baird-Parker medium (Baird-Parker, 1962) is replaced by rabbit plasma, fibrinogen and trypsin inhibitor (Beckers et al., 1984), so that the coagulase reaction can be observed directly on the plate. Compared to Baird-Parker agar, the potassium tellurite concentration is lowered from 100 to 25 mg L⁻¹ (Sawhney, 1986). Selectivity is attained with potassium tellurite, lithium chloride and glycine. Sodium pyruvate is a critical component, essential to both the recovery of damaged Staphylococcus aureus cells and their subsequent growth (Baird-Parker and Davenport, 1965).