The Use of Petrifilm (R) for the Enumeration of Lactococci

Petrifilm (R) aerobic plate counts were compared to Elliker and M17 agar counts for the enumeration of Lactococcus strains. There were no significant do Jbrences between counts obtained with the three methods, which suggests that Petrifilm (R) plates can be used as a time- saving method for the determhlation of laetococci starter populations. The standard method o/ using Petrifilm (R) in which 1 ml of sample is analysed, can be modified to have multiple inoculations on the same dry medium culture plates, such that four aliquots of 0.1 ml are added to a single Petrifilm (R) plate. Counts obtained with the multiple inoculation method did not differ significant of from the standard single inoculation method recommended hy the Petrifilm (R) manufacturer.