Separation from whey of three growth factors for Streptococcus agalactiae.

Wheys of milk and colostrum were treated with ethanol and the concentrated supernatant fluids were subjected to chromatographic procedures (anion exchange resin, using distilled water as eluent). The fractions were tested for capabilities to stimulate the growth of Streptococcus agalactiae in a mixture (1:32) of pasteurized milk and steamed milk. Three stimulatory factors (F), designated F-1, F-2, and F-3, were separated; F-1 was nonionic, and F-2 and F-3 were cationic. A mixture containing any 2 factors gave greater stimulation than either factor tested alone, and a mixture of all 3 gave the greatest stimulation. The F-2 activity was attributed to cystine.