Methanethiol production by coryneform bacteria: strains from dairy and human skin sources and Brevibacterium linens

In work on Cheddar cheese flavour, methanethiol-producing coryneform bacteria were isolated from milk and cheese and their characteristics have been described (Sharpe, Law & Phillips, 1976). As the optimum temperature for growth of these strains was 30 to 37"C, and they tolerated 15 % NaCl, these authors suggested that the strains might originate from the skin. Investigations of coryneform bacteria from human skin have shown that organisms with a similar cell-wall pattern are common members of the diphtheroid skin flora (Pitcher, 1976). Preliminary work showed that many of these organisms produced methanethiol from L-methionine. This paper describes characteristics of some of the methanethiol-producing dairy and skin strains of coryneform bacteria having meso-diaminopimelic acid as their cell-wall diamino acid. Strains of Brevibacterium linens were included, as many characteristics of these organisms (Yamada & Komagata, 1970, 1972a, b) were similar to those of our strains. METHODS The 24 strains examined in detail are listed in Table I. In addition, four orange-pigmented isolates from Limburger and Meshanger cheeses and three orange-pigmented strains from sea fish, described by Mulde