Answer:
Clostridium perfringens show stormy fermentation in litmus milk medium. Lactose in the medium is fermented to organic acid and gas by the organism. Acid changes the colour of the indicator litmus from blue to red. Acid coagulates casein (milk protein) in the medium to form acid clot. Due to the vigorous production of gas, the clot gets disrupted. The paraffin seal is pushed upwards and shreds of clot can be seen on the sides of the test tube.This type of fermentation is called stormy fermentation