Roles played by bacterial and autolytic enzymes in the production of volatile sulphides in spoiling North Sea cod (Gadus morhua)

The roles played by bacterial and autolytic enzymes in the production of volatile sulphides (hydrogen sulphide, methyl mercaptan and dimethyl sulphide) in spoiling iced cod have been investigated. The data show that the volatile sulphides arise as the result of the microbial degradation of cyst(e)ine and methionine. Thirteen Pseudomonas spp. have been investigated. All liberate hydrogen sulphide and methyl mercaptan. In addition to methyl mercaptan formation from methionine, six strains also produce dimethyl sulphide. There is no evidence to show that autolytic enzymes are directly involved in the production of volatile sulphides in chill‐stored North Sea cod.