Spores of clostridium perfringens are killed within 5 minutes by boiling, it is also killed by autoclaving at 121 degree Celsius for 15 minutes. But spores of clostridium perfringens which produce food poisoning are heat resistant. Clostridium perfringens produces multiple exotoxins and is classified into five types (A to E). The most impoant exotoxin alpha toxin, is a phospholipase that hydrolyzes lecithin and sphingomyelin, thus disrupting the cell membranes of various host cells, including erythrocytes, leukocytes, and muscle cells. Gas Gangrene occur due to alpha toxin. In this, infection passes along the muscle bundles, producing rapidly spreading edema and necrosis as well as conditions that are more orable for growth of the bacteria. Ref: Sherris Medical Microbiology, 5th Edition, Chapter 29; Principles and Practice of Clinical Bacteriology By Stephen H. Gillespi, 2nd Edition, Page 569; Textbook of Microbiology and Immunology By Parij, Page 239