Bacteriological Peptones from Fish Flesh

Peptones were prepared from fish flesh by hydrolysis with (1) tryptic or peptic enzymes derived from fish digestive tracts, (2) inorganic acids followed by neutralization of the reaction mixture with an ion exchange resin, calcium hydroxide or barium hydroxide, and (3) sodium hydroxide followed by neutralization with an ion exchange resin. It was found that only those peptones which were prepared by enzyme hydrolysis consistently supported good growth of six Streptococcus haemolyticus cultures and of one Clostridium botulinum type E culture, and that these peptones were generally superior to three commercial peptones in supporting growth of the haemolytic streptococci.