Co-incubation of Clostridium botulinum with protective cultures

Potential neurotoxin production by psychrotrophic clostridium botulinum is the significant food safety risk in refrigerated foods of extended durability. Protective cultures (PC), nisin-producing Lactococcus lactis (6.3 x 10(5) cfu/ml) and pediocin A-producing Pediococcus pentosaceus (10(7) cfu/ml). were co-incubated with C. botulinum type B (6.2 x 10(2) cfu/ml) in tryptose, peptone, glucose and yeast extract broth for 31 days at 5 Degrees Celsius, 14 days at 10 degrees celsius and for 10 days at 15 degrees celsius. Bacterial populations, PH, botulinal toxin and bacteriocin production were measured. At 5 degrees celsius, the populations of all species did not change during the incubation. At 10 and 15 degrees celsius, the PCs increased by 1-3 log. At 15 degrees celsius, C botulinum increased by 1.5-3 log and was not inhibited by the PCs. At 10 degrees celsius, this pathogen was not detected after 10 days of co-incubation. The reduction in C, botulinum population coincided with the nisin level produced by L. Lactis exceeding 100 IU/ml, but it was not rapid enough to prevent botulinal toxin formation.