Effect of Various Bacteria on Diacetyl Content and Flavor of Butter

The literature on effect of different microorganisms on diacetyl and acetylmethylcarbinol has been reviewed in a previous paper (2). Following observations on destruction of diacetyl by Pseudomonas putrefaciens (2), it became apparent that other microorganisms also were able to destroy aroma in commercial butters. Virtanen and eoworkers have reported that some organisms isolated from butter, including B. punctatum, B. vulgatus and a mixture of yeasts, destroyed diacetyl and acetylmethylcarbinol in milk ( As a result of these reports and our own observations, studies were undertaken to determine the extent to which different bacterial species isolated from creamery water supplies and defective commercial butter affected diacetyl content of experimental butters. The study was extended to determine the effect of a wide variety of bacterial species on diacetyl added to sterile milk. Some trials were included to determine change in diacetyl content during storage of representative commercial butters, some of which were known to contain diacetyl-destroying bacteria.