Using bacteriophages of lactococci collected from the industry over more than two decades,
we have compared the previously morphologically defined bacteriophage types (Lembke et al.,
1980; Teuber & Lembke, 1983) by exhaustive electron microscopic characterization, by
DNA-DNA hybridization, and by electrophoresis of bacteriophage proteins. Evidence is
presented for the existence of at least seven genetically distinct virulent phage types and two
temperate phage types, one of these being clearly related to a virulent type. The main three
phage types (Pool, P008, P335) collected in Germany are similar to those already described in
the literature (Coveney et al., 1987; Jarvis, 1984a) and occur throughout the world.