Isolation of galactose-fermenting thermophilic cultures and their use in the manufacture of low browning Mozzarella cheese

The objectives of this study were to isolate galactose-fermenting, galactose-nonreleasing strains of Streptococcus and Lactobacillus and to use these strains as starter cultures in the manufacture of low browning Mozzarella cheese. Four Streptococcus isolates having the desirable phenotype, combined with a Lactobacillus helveticus strain, were acceptable as starter cultures based on activity tests. Fifteen vats of Mozzarella cheese were produced, in triplicate, representing four experimental treatments (made with galactose-nonreleasing strains) and one control (made with a galactose-fermenting, galactose-releasing Streptococcus). Analyses were performed on cheese after 5 and 28 d of refrigerated storage. The lactose and galactose content of cheese remained constant or decreased over the 28-d testing period for all experimental treatments. The galactose content in the control cheese increased over the testing period and was significantly higher by d 28 than in the test cheeses. Browning was greatest on d 28 and at the more severe baking conditions. Control cheese browned more than experimental cheeses did. Melt behavior and free oil formation were generally not affected by treatment. The results indicated that the galactose-fermenting, galactose-nonreleasing strains could be used to make low browning Mozzarella cheese