Use of Galactose-Fermenting Streptococcus thermophilus in the Manufacture of Swiss, Mozzarella, and Short-Method Cheddar Cheese

Galactose-fermenting (galactose-posirive) strains of Streptococcus tbermopbilus, alone and combined with galactosepositive and galactose-negative strains of Lactobacillus bulgaricus, were used as starter cultures in the manufacture of Swiss and Mozzarella cheese and were paired with Streptococcus lactis (also galactose-positive) in short-method Cheddar cheese manufacture. Experimental Swiss cheese made with the galactosepositive Streptococcus tbermopbilus starter alone contained a large amount of galactose (ca. 26 to 28 /amol/g of curd) 28 h after hooping compared with control Swiss (< 2/amol/g) made with a nongalactose fermenting strain of Streptococcus tbermopbilus and a galactosepositive strain of Lactobacillus bulgaricus. Mozzarella and short-method Cheddar made with only galactose-positive Streptococcus tbermopbilus also contained large amounts of galactose. Swiss cheese made with a galactose-positive strain of Streptococcus tberrnopbilus and a galacrose-negative strain of Lactobacillus bulgaricus had little galactose remaining after 28 h, indicating that the Lactobacillus had a stimulatory effect on galactose metabolism in Streptococcus tbermopbilus. These results indicate that galacrose-fermenting Streptococcus tbermopbilus may have limited potential when used as single strain starter cultures in Swiss cheese, but may be useful when combined with galactose-positive Lactobacillus in the manufacture of Mozzarella cheese.