Abstract
The ability of lactic streptococci to utilize unhydrolyzed sodium caseinate as the nitrogen source in an otherwise chemically defined medium seems to be a strain rather than a species characteristic. This characteristic therefore appears to have little value as an aid in classification although it might have some importance in selection of starter cultures for cheese manufacture. None of the enterococci examined grew with unhydrolyzed sodium caseinate as the sole nitrogen source. However, Streptococcus liquefaciens and Streptococcus zymogenes appeared to utilize sodium caseinate when small amounts of casein hydrolyzate were added to the medium.