Submitted to: Journal of Agriculture and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 1, 2006
Publication Date: December 1, 2006
Citation: Smith, D.J., Anderson, R.C., Huwe, J.K. Effect of sodium [36cl]chlorate dose on total radioactive residues and residues of parent chlorate in growing swine. Journal of Agriculture and Food Chemistry 54:8648-8653. Interpretive Summary: Each year thousands of US consumers become ill because they have eaten food products that are contaminated with pathogenic bacteria. Intense efforts have been made during the last decade to eliminate pathogenic contamination from food animals. To date, no single strategy to eliminate pathogens from food animal products has been widely accepted. A new pre-harvest food safety strategy has been developed that has been shown to greatly reduce, or even eliminate gram-negative pathogens from cattle. Use of this new feed additive has not been approved by regulatory organizations because it is not known whether residues present in edible tissues of treated animals represent a health risk. The purpose of this study was to determine the effect that the dose of a new chlorate based additive has on residues of chlorate in edible tissues of swine. For all of the doses tested, chlorate residues in liver, kidney, muscle, and fat fell well below amounts that the FDA have estimated to be safe. Further research on the chlorate-based product is warranted because it could have a significant impact on lowering the incidence of harmful bacteria on meat products, and because residues of the product fall below levels that regulatory agencies have estimated to be safe.
Technical Abstract: An experimental chlorate-based product has shown to be efficacious in eliminating economically important, Gram-negative human pathogens in the gastrointestinal tracts of food animals. Prior to the commercial marketing of such a product, the magnitude and chemical nature of residues remaining in edible tissues must be determined. Thus, the objectives of this study were to determine the tissue distribution and elimination of sodium [36Cl]chlorate in orally dosed swine. Three sets of hogs, each consisting of a barrow and a gilt, were orally dosed with a total of 20, 40, or 60 mg of sodium [36Cl]chlorate per kg body weight via the drinking water. Urine and feces were collected throughout the 30-hour study. Twenty-four hours after the last exposure to [36Cl]chlorate, each hog was slaughtered and both edible and inedible tissues were collected. Urine and tissue samples were analyzed for total radioactive residues and for chlorate metabolites. Elimination of radioactivity in urine averaged 81.6, 83.7, and 83.9% of the total dose for the low, medium, and high doses, respectively. Fecal elimination of radioactivity averaged 1.1% of the dosed radiochlorine across all doses. Parent chlorate always represented greater than 97.4% of the urinary radiochlorine with the remaining radiochlorine being excreted as chloride ion. Chlorate represented 39 to 77% of fecal radioactivity, depending upon dose. Chlorate concentrations in edible tissues ranged from 0.01 to 0.49 ppm with residues in liver and skeletal muscle being generally lower than those in kidney and adipose tissue. Chlorate residues were concentrated in thyroid tissues (7.7 to 25.4 ppm) relative to edible tissues. No evidence for the presence of chlorite was observed in excreta or in tissues. Results of this study suggest that further development of chlorate as a pre-harvest food safety tool in swine merits consideration.