Acceleration of nitrosamine formation at pH 3.5 by microorganisms.

Rate enhancements of from 12 to 49-fold occurred when dihexylamine was nitrosated at pH 3.5 in the presence of bacteria and yeast cells at a concentration of 12 mg/ml. Rates were similar in the presence of either boiled or unheated cells. The magnitude of the rate enhancement for nitrosation of other amines depended on the alkyl chain length. A nonenzymatic mechanism involving hydrophobic interactions of the precursor amines and cellular constituents is proposed.