[Functional properties of plasmids in lactic streptococci]

For over half a century studies of the lactic Streptococci have reported instability of several metabolic properties vital successful dairy fermentation. Little has been done explain this instability, however, and only in the last 10 years or so, with the advent of techniques for studying genetic composition of lactic Streptococci, has it become possible to explanations for this phenomenon. It is now well established that diversity of plasmid sizes are found within strains of lactic Streptococci. Further it has been demonstrated that these organisms characteristically harbour many plasmid species.