Optimal Temperature and Time for Lactic Coagulation of Milk Containing Antibiotic: Evaluation of Yogurt Fermentation Parameters

The presence of antibiotics in milk is one of the problems of dairy production units, especially yogurt and cheese, which leads to a decrease in lactic coagulation. Here, to assess the incubation conditions for fermentation of milk containing the antibiotic, concentrations of ۵۰,۷۵,۱۰۰, and ۲۰۰ parts-per-billion(ppb) of tetracycline were added to each liter of milk. The inoculation process with starter culture was performed at three temperatures (۳۵,۴۵,۵۰°C). Afterward, pH, acidity, oxidation-reduction potential, and lactic coagulation of yogurt were evaluated. The results showed the existence of antibiotics in milk affects the quality and physicochemical properties of yogurt. However, antibiotic concentration and change in incubation temperature play a crucial role in the lactic coagulation of yogurt, such that the best lactic coagulation was observed at ۵۰°C and a concentration of ۵۰ ppb. Hence, in tetracycline concentrations less than ۷۵ppb, a process temperature of ۵۰°C and incubation time of ~۱۰h is recommended for the fermentation of milk containing antibiotics.

کلیدواژه ها:

Antibiotics residues ، Yogurt ، Fermentation parameters ، incubation temperature