Clostridium perfringens is cultured on both halves f this egg yolk agar. This test is used to detect-

Ans. C. Alpha toxin.a. Clostridium perfringens strains produce alpha-toxin The toxin possesses Lecithinase, phospholipase C, sphingomyelinase and biological activities causing hemolysis, lethality and dermo necrosis,b. The figure shows the Nagler reaction which demonstrates the Lecithinase activity of the alpha toxin. Bacterial Lecithinase break down this lecithin (a normal component of egg yolk) to an insoluble diglycerides resulting in an opaque halo, surrounding the colony when grown on the egg yolk agar medium.