Relationship of Titratable Acidity to pH of Wheys Produced by Streptococcus cremoris in Different Skim Milks

Abstract

Twenty-seven single-strain cultures of Streptococcus cremoris to which Leuconostoc cremoris had been added and six mixtures produced, in pasteurized mixed-herd skim milk obtained in June, wheys whose titratable acidities at pH 4.6 were constant (.46 to .48%). Titratable acidities for wheys produced by fast strains of S. cremoris were not detectably different from those for wheys produced by slow strains. Those for strains of S. cremoris with which L. cremoris grew well were not detectably different from those for strains with which L. cremoris grew poorly. Corresponding titratable acidities for wheys produced from four skim milks obtained in November were higher (.52 to .54%). Addition of 1.5% nonfat dry milk or ash prepared from this amount of nonfat dry milk to the June skim milk resulted in the production of wheys whose titratable acidities were similar to those for the wheys produced from the November skim milks. Subsequent to the attainment of pH 4.6, many strains of S. cremoris developed titratable acidity slowly in the June skim milk, which might in practice be interpreted as “starter slowness.” Results suggest occasional use of a pH meter to detect changes in the correct titratable acidity for cutting cottage cheese curd. © 1976, American Dairy Science Association. All rights reserved.