BAIRD PARKER AGAR BASE (FPT)

This medium is a modification of Baird-Parker Medium and is recommended for the selective isolation, enumeration and confirmation of Staphylococcus aureus from food and other specimens. This medium retains the Baird-Parker Agar Base, which has been specifically formulated to resuscitate injured cells. This medium differs from Baird-Parker Medium in that the egg yolk emulsion has been replaced by fibrinogen, rabbit plasma and trypsin inhibitor. The fibrinogen was added to enhance the coagulase reaction in the medium. The addition of rabbit plasma was found to be more specific for the coagulase activity when compared to other sources of plasma. Trypsin inhibitor was added to prevent fibrinolysis. Some strains of Staphylococcus aureus are sensitive to potassium tellurite when used at 0.01% w/v in Baird Parker Agar. This modification of Baird Parker agar base gives comparable growth and selectivity to that achieved on Baird-Parker agar base. The reduction in potassium tellurite concentration in Baird Parker agar base results in Staphylococcus aureus strains forming white, grey or black colonies, which are surrounded by an opaque halo of precipitation, i.e. the coagulase reaction.
On this medium Staphylococcal coagulase positive colonies are white to grey-black surrounded by an opaque zone of coagulase activity within 24-40 hours of incubation at 35?C. Reduction in tellurite is necessary because of absence of egg yolk emulsion. This results in translucent agar and white to grey coloured colonies of Staphylococci. For quantitative results select 20 – 200 colonies. Count Staphylococcus aureus like colonies and test them for coagulase reaction. Report Staphylococcus aureus per gram of food.

for the isolation and enumeration of coagulase positive Staphylococci from food and other materials