The preparation and use of media based on a simple fish waste extract

An aqueous extract of trypsin-degraded fish waste is a good substitute for beef extract in culture media. With beef extract and proteose peptone, it promoted luxuriant growth and staphylococcal toxin production. Though growth occurred in dilute solutions of the extract alone, alpha-toxin production was suppressed. It was synergistic with proteose peptone in the production of alpha-toxin. Separated fish lipids may be used to demonstrate lipase activity.