Effect of Spoilage Bacteria on Biacetyl Content and Flavor of Cottage Cheese

Abstract

Chemical analyses showed that the desirable aromatic flavor of cottage cheese is dependent to a large extent on biacetyl content. Cottage cheese samples low in biacetyl invariably were flat and less palatable whereas samples with high concn. had a typical pleasing aroma and flavor. Cultures of Pseudomonas viscosa and P. fragi destroyed almost all biacetyl contained in commercial and exptl. samples of cottage cheese within a 24- to 48-hr, period. Frequently the gelatinous curd defect associated with these spp. did not appear until several days after loss of the aroma compound. Alcaligenes metalcaligenes, another organism capable of producing the gelatinous defect, was not as active as Pseudomonas spp. in destruction of biacetyl. Investigations on the chemical pathway of destruction of biacetyl indicate that it is primarily converted to acetylmethylcarbinol by Pseudomonas spp. However less than half of the depleted biacetyl is accounted for as acetylmethylcarbinol in instances of decrease by A. metalcaligenes.