Delaying toxigenesis of Clostridium botulinum by sodium lactate in ‘sous-vide’ products

Abstract

The effect of sodium lactate and storage temperature on toxigenesis by proteolytic (Pr) and nonproteolytic (Np) Clostridium botulinum spores inoculated in processed ‘sous‐vide’‐type beef, chicken breast and salmon was explored. Three g samples of beef and salmon homogenates with 0, 2.4 and 4.8% (w/w) lactate and of chicken with 0, 1.8 and 3.6% (w/w) lactate were placed in 24‐well tissue culture plates. The samples were inoculated with 104 spores of pools of Pr (4A + 2B + 2F strains) or Np (4B + 4E strains), vacuum‐packaged in barrier bags, and stored at 16 and 30°C for Pr and at 4, 8, 12 and 30°C for Np for up to 90 d. Lactate at 2.4% in beef and 1.8% in chicken delayed toxigenesis by Np for 40 d at 12°C and by Pr for 28 d at 16°C. Delaying toxigenesis for similar periods of time in salmon required 4.8% lactate and 12°C for Np, and 2.4% lactate and 16°C for Pr. Increasing levels of lactate and decreasing temperature significantly delayed toxigenesis of Cl. botulinum in the ‘sous‐vide’ products.