Inhibition of Clostridium botulinum 62A by Saturated n-Aliphatic Acids, n-Alkyl Formates, Acetates, Propionates and Butyrates

Saturated aliphatic acids (C1 to C20) and n-alkyl formate, acetate, propionate and butyrate esters (C1 to C20) were evaluated to determine the minimum inhibitory concentrations (MIC) necessary to inhibit the growth of Clostridium botulinum 62A in a bacteriological medium. The C1 to C7 and C16 to C20 acids and esters were relatively inactive (MIC > 200 μg/ml). The C8 to C15 acids exhibited some antibotulinal acitivity (MIC = 100 μg/ml), whereas C8 to C15 esters were substantially more inhibitory. The n-alkyl formates, acetates and propionates having C13 to C14 groups gave the highest inhibition, with MIC's of 3.1, 6.3 and 6.3 μg/ml, respectively. The maximum inhibition for the butyrates (MIC = 12.4 μg/ml) was associated with C11 to C12 alkyl groups. A mathematical relationship between activity and alkyl group chain length was derived.