Influence of Ethanol on Probiotic and Culture Bacteria Lactobacillus bulgaricus and Streptococcus thermophilus within a Therapeutic Product

Probiotic bacteria in plain yogurt namely of Lactobacillus ssp. have been reported to treat thrush, diarrhea, athlete’s foot, jock itch and vaginal yeast infections. Lactobacillus delbrueckii ssp. bulgarius (LB-12) and Streptococcus thermophilus (ST-M5) are lactic acid bacteria widely used in the manufacture of yogurt. Alcohol is used in manufacture of some medications such as cough syrups and some products such as eggnog and rum-raisin ice cream. The objectives were to study the effect of food grade ethanol on the growth of yogurt culture bacteria and the physico-chemical characteristics of therapeutic yogurt. The treatments were 0% (control), 2.5%, 5%, and 7.5% v/v ethanol in plain yogurt. The ethanol was incorporated by stirring it into one day old plain yogurt. Product characteristics were studied weekly for a month of refrigerated (4 ̊C) storage. Data were analyzed using Proc Mixed model of Statistical Analysis System. The ethanol amount × storage period interaction effect was significant for Lactobacillus bulgaricus counts while the ethanol amount × storage period effect was not significant for Streptococcus thermophilus counts, viscosity, pH and titratable acidity (TA). Therapeutic yogurts with ethanol, at these concentrations, can successfully be manufactured without adversely influencing counts of its probiotic bacteria over product shelf life.