Spoilage of vacuum‐packed beef by a clostridium sp

An unusual spoilage condition of chill‐stored normal pH vacuum‐packed beef characterised by gross distension (blowing) of the packs and off‐odours perceived on initial opening of the packs as ‘sulphurous’ and subsequently as ‘fruity’, ‘solvent‐like’ and ‘strong cheese’ has been chemically defined. Hydrogen and carbon dioxide were the major components of the headspace gases. Other components included hydrogen sulphide, methanethiol, dimethyl sulphide, dimethyl di‐ and trisulphides, methylthioacetate, l‐butanol, acetic and butanoic acids, and l‐butyl esters of a range of C1‐C6 fatty acids. Published sensory data are consistent with components of this mixture being responsible for the off‐odours detected. When grown in pure culture on beef under identical storage conditions, a Clostridium sp isolated from one of the blown packs produced the same chemical and sensory spoilage characteristics.