Co-incubation of Clostridium botulinum with protective cultures

Abstract

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.