Variants of Streptococcus Lactis which do not Ferment Lactose

Abstract

Four cultures of Streptococcus lactis which did not ferment lactose were isolated from milk. These cultures were shown to agree with typical S. lactis strains in all other respects.It is believed that these cultures represent naturally occurring variants of S. lactis, and this view appears to be borne out by the fact that one strain, after cultivation in milk for ten months, is gradually acquiring the ability to ferment lactose.