The production of a ropy condition in milk is a character occasionally shown by the organisms of the S. lactis group. 'l'his character is, however , one that is rather inconstant and its gain or loss or a variation in its extent is frequently noted in the laboratory in cultures that are very probably pure. In starters also, where the S. lactis type of organisms makes up the largest percent of the flora, the development of ropiness occasionally occurs and when ropy starters are carried thru a number of transfers this ropiness sometimes disappears. The change from ropy to non-ropy cultures of S . lactis and the reverse have recently been studied by plating out one of the types, picking colonies and looking for the other among the cultures developing; the results obtained are herein reported.
Hammer, B. W.
"Studies on ropiness in cultures of Streptococcus Lactis,"
Research Bulletin (Iowa Agriculture and Home Economics Experiment Station): Vol. 5
, Article 1.
Available at: https://lib.dr.iastate.edu/researchbulletin/vol5/iss74/1