Spoilage of beef, lamb and venison by psychrophilic and psychrotrophic clostridial species renders meat unacceptable resulting in financial losses and reduced consumer confidence. A number of clostridial strains, including Clostridium algidicarnis, Clostridium algidixylanolyticum, Clostridium estertheticum, Clostridium frigidicarnis and Clostridium gasigenes, have been implicated in red meat spoilage. Unlike other spoilers, these clostridia are able to grow in anaerobic conditions and at chilled temperatures (some at )1.5°C the optimal storage temperature for chilled red meat). The spoilage they cause is characterised by softening of the meat, production of large amounts of drip (exudates), offensive odours and in the case of C. estertheticum and C. gasigenes production of gas. Spoilage occurs following the introduction of clostridial spores into vacuum packages during processing. Germination of spores is necessary for the growth of vegetative cells, which cause spoilage. Current mitigation strategies focus on good management practice within meat processing plants. However, this is not always sufficient to prevent spoilage. This review summarises the issues associated with meat spoilage because of psychrotolerant clostridia and discusses areas that require further study.

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Aims:  To determine the contamination levels of Cl. estertheticum spores that result in gaseous spoilage of vacuum‐packaged chilled meats, beef and lamb, stored at two different temperatures, −1·5 and 2°C. Methods and Results:  The study consisted of two separate trials using the same processing parameters applied to beef and lamb at two different storage temperatures and six different inoculation concentrations of Cl. estertheticum. A threshold for pack blowing of c. 1 spore per vacuum pack was seen with both beef and lamb stored at −1·5 and 2°C. These results highlight the detrimental effect that increasing Cl. estertheticum spore inoculum concentration has on the onset of blown pack spoilage for both meat species stored at −1·5 and 2°C. Conclusions:  This study demonstrates that storage temperature is an extremely important parameter influencing the onset of blown pack spoilage and that storing meat at −1·5°C significantly delays the onset of blown pack spoilage in comparison with storage at 2°C. Significance and Impact of study:  The results of this study indicate that 1 Cl. estertheticum spore may present a risk of spoilage, and thus hygienic carcass dressing is critical to keep contamination to a minimum and maximize storage life of the vacuum‐packed chilled product.

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Aims:  To determine germination triggers of Clostridium frigidicarnis, an important spoilage bacterium of chilled vacuum‐packed meat. Methods and Results:  Germination of Cl. frigidicarnis spores in the presence of a range of potential nutrient and non‐nutrient germinants was tested by monitoring the fall in optical density and by phase‐contrast microscopy. The amino acid l‐valine induced strong germination when paired with l‐lactate in sodium phosphate under anaerobic conditions. Several other amino acids promoted germination when paired with l‐lactate in sodium phosphate and the co‐germinants NaHCO3 and l‐cysteine. Heat activation, while not necessary for germination, increased the rate of germination. Spore germination was not observed when spores were incubated aerobically. Conclusions:  Spores of psychrotolerant Cl. frigidicarnis germinated in the presence of l‐valine in combination with l‐lactate in sodium phosphate buffer under anaerobic conditions. Significance and Impact of the Study:  Anaerobic conditions, l‐valine and l‐lactate, have been identified as triggering germination in Cl. frigidicarnis, and are all present in packs of fresh, vacuum‐packaged, red meat. This new information adds to what is known about red meat spoilage by cold tolerant clostridia and can be used to develop intervention strategies to prevent meat spoilage.