Chemical inactivation of protein toxins on food contact surfaces.

We compared the kinetics and efficacies of sodium hypochlorite, peracetic acid, phosphoric acid-based detergent, chlorinated alkaline detergent, quaternary ammonium-based sanitizer, and peracetic acid-based sanitizer for inactivating the potential bioterrorism agents ricin and abrin in simple buffers, food slurries (infant formula, peanut butter, and pancake mix), and in dried food residues on stainless steel. The intrinsic fluorescence and cytotoxicity of purified ricin and abrin in buffers decreased rapidly in a pH- and temperature-dependent manner when treated with sodium hypochlorite but more slowly when treated with peracetic acid. Cytotoxicity assays showed rapid and complete inactivation of ricin and crude abrin in food slurries and dried food residues treated 0-5 min with sodium hypochlorite. Toxin epitopes recognized by ELISA decayed more gradually under these conditions. Higher concentrations of peracetic acid were required to achieve comparable results. Chlorinated alkaline detergent was the most effective industrial agent tested for inactivating ricin in dried food residues.