Chlorinating poultry chiller water: the generation of mutagens and water re-use

The purpose of this study was to assess the potential generation of mutagens by chlorination of water used to chill poultry carcasses. Unchlorinated chiller water from a nearby poultry processing plant was chlorinated to different levels in the laboratory. Residues of dichloromethane extracts of the treated water were tested for mutagenicity with the Ames Salmonella reverse mutation system. The rate of disappearance of added chlorine from the chiller water was also monitored using ferrous ammonium sulphate titration. The results showed a fast rate of disappearance of added free chlorine, only some of which reappeared as combined available chlorine. No mutagenic activity could be demonstrated at chlorination levels up to 100 ppm, but activity rose above 250 ppm, and a dose-response relationship was demonstrated. The significance of these findings for poultry processing is discussed.