Substrate utilization during incubation in meat juice medium of psychrotolerant clostridia associated with blown pack spoilage

Abstract

Several new species of psychrophilic or psychrotolerant clostridia have been identified in recent years. Some of these may be involved in ‘blown pack’ spoilage (BPS) of vacuum packaged beef. Organisms that cause BPS must produce large volumes of gas while utilizing substrates available in raw meat. Therefore, Clostridium algoriphilum, Clostridium algidixylanolyticum, Clostridium bowmanii, Clostridium frigoris, Clostridium frigidicarnis, Clostridium gasigenes, Clostridium lacusfryxellense, Clostridium psychrophilum, Clostridium tagluense and Clostridium vincentii were grown in meat juice medium (MJM), and changes in substrate concentrations were monitored to assess the potential for gas production by each organism. All 10 species were able to grow exponentially on glucose with simultaneous hydrolysis of glycogen, reaching maximum values for absorbance at 600 nm of 0.3–1.90. All ceased growing when glucose and glycogen were still detectable in the growth medium. C. frigidicarnis utilized most of the amino acids available in MJM and reduced the concentration of total amino acids by 10 mM. The other 9 species caused little or no reduction in amino acid concentrations. C. algidixylanolyticum and C. frigidicarnis utilized glucose, glycogen and lactate simultaneously during growth and after growth ceased. C. algoriphilum and C. frigoris commenced utilization of lactate, while continuing utilization of glucose and glycogen, only after growth ceased, but utilization of lactate by C. algoriphilum was weak. C. psychrophilum ceased utilization of glucose and glycogen but initiated weak utilization of lactate after growth ceased. The other 5 species did not utilize any substrate after growth ceased. The utilization of glucose, glycogen and relatively large amounts of lactate by C. algidixylanolyticum, C. frigoris, and C. frigidicarnis after growth ceased indicates that these organisms have the potential to cause BPS. The other 7 species appear to lack such potential.