Isolation and Ultrastructure of Bacteriophages of Group N (Lactic) Streptococci

Abstract

During a two year screening period, approximately 200 phages active against lactic streptococci have been isolated in a cheese factory from raw milk, cheese whey and starter culture using an indicator set of 24 strains of Streptococcus lactis, 17 strains of S. cremoris and 16 strains of S. lactis subsp. diacetylactis. Electron microscopy of these phages suggests the existence of at least 14 distinct morphological types. The ultrastructural and host range properties of 14 typical phage types are described and discussed.