Biochemical Basis for Nitrite-Inhibition of Clostridium botulinum in Cured Meat

The biochemistry of the anaerobic spore-forming clostridia and the chemistry of the nitrite reactivity during meat curing are reviewed. Direct and indirect mechanisms for nitrite inhibition of Clostridium botulinum growth and toxin formation are presented. The "Perigo effect" produced by heating nitrite in laboratory media may be produced by artifactual oxidants, and is not identical to that produced in cured meats. Inhibition of C. botulinum by nitrite in cured meats is most likely due to several interacting mechanisms: (a) reaction and oxidation of cellular biochemicals within the spores and vegetative cells; (b) restriction of use of iron (or other essential metal ions) through inhibition of solubilization, transport, or assimilation, thus interfering with metabolism and repair mechanisms and (c) cell surface membrane activity limiting substrate transport by the outgrowing cell.