Leuconostoc carnosum associated with spoilage of refrigerated whole cooked hams in Greece

Abstract

A polyphasic taxonomic approach was used to identify a major atypical group of gas-forming, arginine-negative lactic acid bacteria associated with spoilage of whole (nonsliced) refrigerated (4 degrees C) cooked hams produced in two Greek industrial meat plants. Biochemical characterization revealed that the ham isolates shared their phenotypic properties with Leuconostoc carnosum, Weissella viridescens, and Weissella hellenica. However, gas chromatographic analysis of cellular fatty acids clearly differentiated the ham isolates from the Weissella spp. None of the isolates contained eicosenoic acid (n-C20:1), which is typically synthesized by W. viridescens, but all strains contained high amounts of C 19cycl acid, which is absent in W. hellenica and has been found in trace amounts in W. viridescens. All strains had similar cellular fatty acid profiles, which were qualitatively similar to those of the cellular fatty acids of L. carnosum. In addition to the phenotypic and chemotaxonomic tests, three representative isolates were studied using a lactic acid bacteria database, which employs 16S and 23S HindIII restriction fragment length polymorphism patterns as operational taxonomic units in a numerical analysis. The isolate patterns were identical to those of the L. carnosum type strain, NCFB 2776T. Based on the polyphasic taxonomic approach, the dominating lactic acid bacteria group was identified as L. carnosum.