PROPERTIES OF SUBSTANCES INHIBITORY TO PSEUDOMONAS FRAGI PRODUCED BY STREPTOCOCCUS CITROVORUS AND STREPTOCOCCUS DIACETILACTIS

Evidence is presented that the inhibitory substances for Pseudomonas fragi produced by Streptococcus citrovorus and Streptococcus diacetilactis are not similar to nisin. The substances were stable to heat at an acid or basic pH. Trypsin and chymotrypsin had no effect on the inhibitory substances. A distillation procedure was used to separate a volatile inhibitor identified as acetic acid. Rf values for inhibitors in the residue fraction from the distillation procedure were similar to some of the compounds in the Krebs cycle. © 1968, American Dairy Science Association. All rights reserved.