Effects of Composition of Substrate and Inoculation Technique on Plate Counts of Bacteria in the Northern Baltic Sea

Medium V has been developed for the enumeration of total colony forming units (TCFU) of heterotrophic bacteria in coastal waters of the Northern Baltic Sea. Medium V gave higher counts than ZoBell's medium 2216 E with samples taken over six months. The difference between counts for the inshore samples was significant. A comparison of ‘spread’and ‘pour’plates suggested that the former was superior, especially for the enumeration of TCFU of psychrophiles. ‘Spread’plating should be used for samples whose natural temperature would suggest the presence of psychrophiles.