Effect of water activity aw of milk on acid production bt Streptococcus thermophilus and Lactobacillus bulgaricus

LARSEN R.F.; AÑON, MARÍA CRISTINA

JOURNAL OF FOOD SCIENCE

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 1989 vol. 54 p. 917 - 921

0022-1147

Rate of acid production by Lactohacillus hulguricus ATCC 11842 andStreptococcus thermophilus ATCC 19258 was measured at tempcratures between 30°C and 50°C in milks which had been adjusted from0.992 to 0.943 aw, with glycerol. Data were fitted with a nonlinearmathematical model of the Arrhenius type. Decrease of a, inhibitedacid production by both organisms. Range of temperatures, withinwhich the rate of acid production was higher than 50% of the optimalrate, was also narrowed with both species. Optimal temperatures ofacid production were unaffected by changes of aw. Minimum aw, foracid production was always lower when aw, of milk was adjusted withglucose or sucrose than with glycerol.