699. Lactobacilli in Cheddar cheese: 1. The use of selective media for isolation and of serological typing for identification

Abstract

A comparison of three different media, yeast dextrose agar, tomato dextrose agar and acetate agar (which is selective for lactobacilli) showed that the acetate medium was satisfactory for the isolation and counting of lactobacilli from Cheddar cheese during ripening. Lactobacilli were isolated on this medium in the early stages of ripening when the large numbers of starter streptococci growing on the other media were completely suppressed. Lactobacilli isolated were identified biochemically and serologically. Serological typing was found to be a useful method of identifying large numbers of isolates and of assessing the incidence and distribution of particular types in the cheese.We wish to thank Dr A. T. R. Mattick for his interest and helpful advice in this work; Dr L. A. Mabbitt for preparation of the cheese samples; Miss H. R. Chapman for making the experimental cheese; and Mrs P. Jarrett for technical assistance.