Objective 1: Develop and (or) validate sensitive and accurate analytical tools to rapidly detect and quantify chemicals in food animals, food animal products, or other foods. Sub-objective 1.A: Validate the usefulness of rapid screening tests in ante-mortem matrices (urine, plasma, serum, saliva, milk, etc.) for predicting post-mortem tissue residues and(or) animal exposures to target compounds. Sub-objective 1.B: Develop and validate on-site detection methods for new and emerging xenobiotic residues. Objective 2: Investigate the kinetics of uptake, metabolism, distribution, and (or) the elimination of chemicals in and from food animals and (or) produce with the goal of reducing public exposure to chemical residues in foods. Sub-objective 2.A: Determine the effect of mediators of inflammation on drug metabolizing enzymes, drug clearance, and violative residues in food animals using flunixin meglumine as a model compound. Sub-objective 2.B: Determine the fate and distribution of chlorine dioxide gas in foods treated for pathogen or rot-organism remediation. Objective 3: Determine the fate of endogenous reproductive hormones, antibiotics, and or other chemicals, including biologically-active metabolites or degradation products in wastes of food animal or in food processing systems. Sub-objective 3A: Determine the partitioning of chemical residues into cream, curd, whey, and water fractions during milk processing. Sub-objective 3B: Determine the fate of estrogens in animal wastewater systems.
The broad objective of this project is to determine the fate of natural and manmade chemicals in food animals and in food animal systems (wastes, soil, water). Three broad classes of chemicals will be targeted for study: (1) veterinary drugs or feed additives administered to food animals under extra-label use conditions, (2) endogenous steroid hormones, and (3) novel developmental chemicals of potential utility to the livestock industry. Use of veterinary chemicals in an extra-label manner without knowledge of residue depletion kinetics has led to unsafe residues in meat products. Endogenous steroid hormones excreted by livestock are highly potent endocrine-disrupting compounds that are thought to disrupt the development of aquatic species after their entry into surface waters. Finally, chemical technologies developed by the ARS, e.g., chloroxyanions and nitro compounds, are active against Salmonella and E. coli pathogens in livestock immediately prior to slaughter, but the impacts of chemical residues in meat products have not been fully investigated for these compounds. Regardless of the chemical class being investigated, the development of sensitive and accurate analytical tools is critical completion of the objectives. Therefore, a significant portion of the project is devoted to developing the analytical tools required to ensure success of the project. The overall project goal is to understand the broad impact that chemical residues play in influencing food and environmental safety.
Objective 1: A zilpaterol lateral flow assay was developed and validated for use in a live-phase study. The applicability of the rapid screening assay for use in live animals and in tissues is currently being tested. Further, a mass spectrometers/mass spectrometers (MS/MS) based rapid screening assay is being developed and validated to test the concept of having a sensitive and semi-quantitative screening available that will return unambiguous (mass-selective) results within minutes of sample collection. A study in sheep is currently underway to test whether mass-spectrometry and immunochemical rapid screening assays have sufficient selectivity and sensitivity to be used in the field. An antibody towards the veterinary antibiotic paromomycin was generated in rabbits. The sensitivity and selectivity of the antibody towards paromomycin has been tested and an enzyme linked immunosorbent assay (ELISA) is being developed for use in measuring the paromomycin in animal matrices. Objective 2: A study was completed determining the effects of chlorine dioxide sanitation on total coliform content, germination rates, and the presence of chemical residues on alfalfa seeds and in alfalfa sprouts. Carbon-14 labeled dicoumarol was synthesized and dosed to goats to determine the extent of absorption, distribution, and elimination of the mycotoxin in a ruminant species. Analyses are currently being conducted to determine the metabolic transformation of dicoumarol and to learn the chemical identity of residues which remain in edible tissues. Objective 3. A study investigating the partitioning of numerous xenobiotic compounds into milk fractions (skim, cream, whey, and protein) was completed and the data are being used to construct a partitioning prediction model. Halogenated estradiol analogs were used in a field trial to determine the transmission of estrogen compounds through lagoon digestion and field applications into ground water. The halogenated estrogen can be distinguished from trace levels natural estrogens already present in the environment. The second year of a rainfall simulator study investigating the fate of estrogen compounds and estrogenic activity present in poultry manure was conducted.
1. Rapid screening test developed. Zilpaterol is an FDA-approved beta-agonist feed additive that increases feed efficiency, improves growth rate, and produces lean meat in livestock. Several major trade partners with the United States do not allow the import of meat from animals fed zilpaterol and in the U.S. zilpaterol is illegal to use in some food animal species. ARS researchers in Fargo, North Dakota developed a sensitive, selective, inexpensive, and rapid test to determine whether animals have been exposed to zilpaterol. The assay, which is similar to an over-the-counter pregnancy test, can be used on-site with minimal training, and results are obtained in about 10 minutes. The accuracy and sensitivity of the assay was verified in tissues and urine from animals exposed to zilpaterol. This simple and inexpensive assay could be used to determine accidental, illegal, or purposeful zilpaterol exposure.
Cheng, T.D., Shelver, W.L., Hong, C., McCann, S.E., Davis, W., Zhang, Y., Ambrosone, C.B., Smith, D.J. 2016. Urinary excretion of the ß-adrenergic feed additives ractopamine and zilpaterol in breast and lung cancer patients. Journal of Agricultural and Food Chemistry. 64(40):7632-7639.
Smith, D.J., Giddings, J.M., Herges, G.R., Ernst, W. 2016. Distribution, identification, and quantification of residues after treatment of ready-to-eat salami with 36Cl-labeled or nonlabeled chlorine dioxide gas. Journal of Agricultural and Food Chemistry. 64:8454-8462.
Smith, D.J., Shelver, W.L., Marx, A. 2016. Detection of residues in urine and tissues of sheep treated with trace levels of dietary ractopamine HCl. Journal of Animal Science. 94:5423–5433. doi:10.2527/jas2016-0899.
Shelver, W.L., Schneider, M.J., Smith, D.J. 2016. Distribution of flunixin residues in muscles of dairy cattle dosed with lipopolysaccharide or saline and treated with flunixin by intravenous or intramuscular injection. Journal of Agricultural and Food Chemistry. 64:9697-9701. doi:10.1021/acs.jafc.6b04792.
Shelver, W.L., Chakrabarty, S., Smith, D.J. 2017. Comparison of lateral flow assay, kidney inhibition swab, and liquid chromatography-tandem mass spectrometry for the detection of penicillin G residues in sow urine. Journal of Agricultural and Food Chemistry. 65:1778-1783. doi:10.1021/acs.jafc.6b05049.
Shappell, N.W., Shelver, W.L., Lupton, S.J., Fanaselle, W., Van Doren, J.M., Hakk, H. 2017. Distribution of animal drugs among curd, whey, and milk protein fractions in spiked skim milk and whey. Journal of Agricultural and Food Chemistry. 65:938-949. doi:10.1021/acs.jafc.6b04258.
Smith, D.J., Herges, G.R. 2017. Stability of sodium chlorate residues in frozen tomato and cantaloupe homogenates. Journal of Agricultural and Food Chemistry. 65(30):6258-6263. doi:10.1021/acs.jafc.7b02520.
Smith, D.J., Kim, M. 2017. Chemical contamination of red meat. In: Schrenk, D., editor. Chemical Contaminants and Residues in Food, 2nd edition. Woodhead Publishing, Oxford. p.451-489.
Casey, F.X., Shappell, N.W., Hakk, H. 2017. Halogenated 17ß-estradiol surrogates: synthesis, estrogenic activity, and initial investigations of fate in soil/water systems. Journal of Environmental Quality. 46(4):802-810. doi: 10.2134/jeq2017.02.0053.