The use of mesophilic cultures in the dairy industry

The use of mesophilic starter cultures, containing group N Streptococcus and Leuconostoc species, in the dairy industry is examined. Bacteriophage attack is identified as the main cause of culture inhibition and criteria used to select stable mixed-strain starter cultures and phage-insensitive defined strains are established. The key aspects of culture propagation and storage are highlighted, as well as bulk-culture protection based on physical exclusion of phage and the use of phage-inhibitory media. Developments in the application of starter culture systems in different countries are examined and show that significant process control and elimination of phage problems can be achieved.