Growth of Thermophilic Starters in Whey Permeate Media

Abstract

Strains of Lactobacillus delbrueckii ssp. bulgaricus, Lactobacillus helveticus, Lactobacillus acidophilus, and Streptococcus thermophilus varied in their ability to grow in whey permeate-based media. Whey permeate alone was a poor medium with a relatively low buffering capacity, which supported the growth of L. delbrueckii ssp. bulgaricus and S. thermophilus only. External pH control and the addition of .1% nonfat dry milk solids and .5 to 1% yeast extract improved the growth and activity of L. delbrueckii ssp. bulgaricus, L. helveticus, and S. thermophilus and made whey permeate-based media comparable with 11% nonfat dry milk as a medium for thermophilic lactic acid starters. Internal pH control, using a phosphate buffer, did not significantly improve the growth of the strains used when compared with the unbuffered medium and was inhibitory to L. helveticus 880. © 1991, American Dairy Science Association. All rights reserved.