'l'he lactic acid producing streptococci show certain differences, some of which must be of importance from the standpoint of the growth of these organisms in dairy products. A classification of this group of organisms has been proposed; it is not presumed to be complete and other types will necessarily be added. The classification is as follows:
Typical S. lactis
Malty S. Iactis—S. lactis var. maltigenes
Ropy S. lactis—S. lactis var. hollandicus
Slow reducing S. lactis—S. lactis var. anoxyphilus
Slow coagulating S. lactis—S. lactis var. tardus
Heat resistant lactic acid streptococci—S. thermophilus
Hammer, B. W. and Baker, M. P.
"Classification of the Streptococcus Lactis group,"
Research Bulletin (Iowa Agriculture and Home Economics Experiment Station): Vol. 7
, Article 1.
Available at: https://lib.dr.iastate.edu/researchbulletin/vol7/iss99/1