Studies on the Chemistry of Cheddar Cheese Making. III. The Conversion of Lactose into Lactic Acid by Starter Cultures

Determinations of acidity, lactose and lactic acid were made at various stages during the souring of milk by starter cultures, both with and without the addition of a neutralising agent. 2. Throughout the fermentation, the increase in acidity of the milk was accounted for quantitatively by the amount of lactic acid produced. 3. In some instances in the early stages of the fermentation a considerable quantity of the lactose appeared to be converted to substances other than lactic acid. 4. Over the whole fermentation the amount of by-products produced from the lactose was small.