Prevalence of cold-tolerant clostridia associated with vacuum-packed beef and lamb stored at abusive and chill temperatures

A survey was conducted for the presence of cold-tolerant (i.e. capable of growing at less than 5°C) Clostridium spp. in fresh vacuum-packed beef and lamb obtained from nine export meat plants. Prevalence was determined before and after storage at abusive (15°C) and non-abusive (-1.5°C) temperatures, and instances of pack failure by "blowing" were recorded. Overall, only three samples (6.7%) were positive for the presence of this group of micro-organisms on initial testing. After storage at 15°C for 8 weeks, cold-tolerant clostridia were found in 51.1% of samples, all of which had "blown". After storage at -1.5°C for 12 weeks, only 2 samples (4.4%) accumulated significant amounts of gas, and both contained cold-tolerant clostridia. With vacuum-packed product stored at 15°C, approximately 29% of the clostridial strains isolated at 15°C were cold-tolerant species capable of growing at less than 5°C. However, none of them were able to grow at -1.5°C. Only psychrophilic and psychrotrophic clostridia were isolated from fresh samples and those stored at -1.5°C.