Bacteriocin production by lactic acid bacteria using ice cream co-product as the fermentation substrate

Ice cream manufacture commonly results in the accumulation of wasted product that contains valuable food-grade quality components, including fat, carbohydrates, and protein. Methods have been developed for recovering the fat from this waste stream, but this results in the generation of a co-product rich in fermentable carbohydrates. This study aimed to investigate the potential for using this co-product as a fermentation substrate for production of antimicrobial peptides, called bacteriocins, by dairy starter cultures. Results showed that Streptococcus thermoph/lus B59671 and Lactococcus lact/s 11454 produced the broad-spectrum bacteriocins thermophilin 110 and nisin, respectively, when the fermentation substrate was melted ice cream, or a co-product generated by a modified butter churning technique. Bacteriocin production varied depending on the brand and variety of vanilla ice cream used in this study. When an alternate enzyme-assisted fat extraction technique was used, S. thermoph/lus metabolism was impaired within the resulting co-product, and thermophilin 110 production was not co-product, but antimicrobial activity was not observed. use as a base medium for future studies to optimize bacteriocin production.