Spore germination of the psychrotolerant, red meat spoiler, Clostridium frigidicarnis

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 NaHCO(3) 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.