ABSTRACT
The genus Clostridium belongs to the family Clostridiaceae, which is composed predominantly of spore-forming anaerobic bacteria, in the form of rods with Gram-positive cell walls. Clostridium is the type genus of the family, containing more than 200 described species, among them Clostridium perfringens. C. perfringens is widely distributed in nature, soil, dust and vegetation. The characteristics most used for C. perfringens identification in food analysis are sulfite reduction, motility, lactose fermentation, gelatin hydrolysis and nitrate reduction. The presence of small numbers of C. perfringens is not uncommon in raw meats, poultry, dehydrated soups and sauces, raw vegetables and certain other foods or food ingredients. Tryptose sulfite cycloserine agar is the medium most frequently used for the enumeration of C. perfringens by direct plating, constituting at the same time an excellent alternative for the enumeration of sulfite-reducing clostridia, due to its ability to suppress the growth of practically all facultative anaerobes that accompany clostridia in foods.
