CASITOSE BROTH

Description

Casitose Broth (Casein Hydrolysate Broth) was developed by Casman and is used for production of Staphylococcal enterotoxin for use in the cat test and in serological studies. As described in APHA, Staphylococci to be tested for enterotoxigenicity should be subcultured into the tubes of Casitose Broth (Casein Hydrolysate Broth) and incubated in an atmosphere containing 30% Carbon – dioxide for 18 – 24 hours at 35?C. Growth obtained by this method is then transferred from each tube in three ml amounts to duplicate flasks containing 100 ml Casitose Broth and the flasks should be incubated as mentioned above for three days. The broth cultures are then centrifuged and supernatant fluid is sterilized by Seitz filtration. The filtrates are then tested for alpha and beta haemolysins and if present then the toxins are denatured by heat or by neutralization with antiserum. After denaturation, filtrates can be injected in the cats to observe if vomiting is induced. Casitose Broth can be solidified with the addition of agar and the cultures grown are used for tests on other animals and in analysis of antigen-antibody systems by agar diffusion technique.