Abstract
The effects were studied of refrigerated storage, repeated fermentation and added sweetening/flavoring materials or alcoholic drinks on the number of bacteria in homemade yogurt. The number of bacteria in the refrigerated yogurt was decreased by approximately one-quarter per week of storage. A slight decrease in the number of bacteria was apparent during repeated fermentation, but it was not practically significant for daily consumption. The sweetening/flavoring materials commonly used for yogurt did not affect the number of bacteria in it. Bacterial growth was suppressed by the presence of a high concentration of ethanol, whereas it was significantly enhanced by a low ethanol concentration. These results indicate the convenience of homemade yogurt for daily consumption when prepared to individual tastes.
