Comparison of pattern recognition techniques for the identification of lactic acid bacteria

Aims: The goal of this study was to evaluate three pattern recognition meth ods for use in the identification of lactic acid bacteria. Methods and Results: Lactic acid bacteria (21 unknown isolates and 30 well- characterized strains), including the Lactobacillus, Lactococcus, Streptoco ccus, Pediococcus and Oenococcus genera, were tested for 49 phenotypic resp onses (acid production on carbon sources). The results were scored in sever al ways. Three procedures, k-nearest neighbour analysis (KNN), k-means clus tering and fuzzy c-means clustering (FCM), were applied to the data. Conclusions: k-Nearest neighbour analysis performed better with five-point- scaled than with binary data, indicating that intermediate values are helpf ul to classification. k-Means clustering performed slightly better than KNN and was best with fuzzified data. The best overall results were obtained w ith FCM. Genus level classification was best with FCM using an exponent of 1.25. Significance and Impact of the Study: The three pattern recognition methods offer some advantages over other approaches to organism classification.