Location: Residue Chemistry and Predictive Microbiology Research2019 Annual Report
1. Develop, validate, and transfer multiclass, multiresidue methods for pesticides, environmental, and emerging contaminants in FSIS-regulated foods, and conduct a survey of food samples for the contaminants. 1A. Simultaneous analysis method for diverse pesticides, legacy and emerging environmental contaminants in meats. 1B. Multiresidue method for food packaging (FP) contaminants in packaged foods. 1C. Conduct a survey of food samples for emerging environmental and FP contaminants. 2. Develop qualitative screening and identification criteria with automated data processing that meets regulatory needs to minimize/avoid false positives and negatives. 3. Develop sample processing methods for regulatory analysis that improve the ability to detect combinations of veterinary drug residues in the same sample preparation. 3A. Simultaneous analysis method for diverse veterinary drugs residues, including aminoglycoside antibiotics, in meats. 3B. Evaluate cryogenic sample processing to achieve meaningful representative sample size of 100 mg in multiresidue analysis of pesticides and veterinary drug residues in foods. 4. Develop automated high-throughput sample processing, preparation, and analysis methods using flow-injection and/or open probe techniques coupled with mass spectrometry to monitor >500 veterinary drugs, pesticides, and environmental contaminants in foods. 5. Develop novel analytical methods for inorganic and organometallic heavy metals [for example forms of mercury (Hg) and arsenic (As)] in foods. 5A. Develop novel analytical methods for mercury speciation and quantification in foods. 5B. Develop novel analytical methods for arsenic speciation and quantification in foods. 6. Develop and use bioanalytical methods (including mass spectrometry) to monitor for antibiotic resistant organisms and/or their biomarkers in conjunction with antibiotic residues in seafood and meats.
The specific approaches for meeting the project’s objectives and milestones are as follows: 1) develop, validate, and transfer multiclass, multiresidue methods for pesticides, environmental, and emerging contaminants in FSIS-regulated foods, and conduct a survey of food samples for the contaminants; 2) develop qualitative screening and identification criteria with automated data processing that meets regulatory needs to minimize/avoid false positives and negatives; 3) develop sample processing methods for regulatory analysis that improve the ability to detect combinations of veterinary drug residues in the same sample preparation; 4) develop automated high-throughput sample processing, preparation, and analysis methods using flow-injection and/or open probe techniques coupled with mass spectrometry to monitor >500 veterinary drugs, pesticides, and environmental contaminants in foods; 5) develop novel analytical methods for inorganic and organometallic heavy metals [for example forms of mercury (Hg) and arsenic (As)] in foods; and 6) develop and use bioanalytical methods (including mass spectrometry) to monitor for antibiotic resistant organisms and/or their biomarkers in conjunction with antibiotic residues in seafood and meats.
Progress was made in all objectives, and the project is progressing according to schedule, except for Objective 6 which will be delayed due to the resignation on 9/30/18 of the scientist leading investigations on antimicrobial resistance. A visiting scientist will begin on 9/1/19 for one year to contribute to Objective 6, and recruitment to fill the vacancy will commence when permitted. Otherwise, Objectives 1A, 2, 3, 4, and 5A are essentially complete. A method for >300 pesticides, veterinary drugs, and environmental contaminants has been validated in food animal tissues using FSIS standards, including qualitative identification involving blind analyses. Due to the purchase of new instrumentation, Objective 5B will use cold trapping – hydride generation – inductively-coupled plasma – mass spectrometry instead of or in addition to the originally planned graphite furnace - atomic fluorescence spectroscopy for analysis of inorganic arsenic. The food packaging study in Objective 1B has been initiated and new instrumentation (gas chromatograph – orbital ion trap mass spectrometer) has been obtained through a material transfer research agreement to conduct nontargeted analysis of food packaging components in addition to targeted analysis as originally planned. The validation and monitoring aspects of Objectives 1B and 1C will be completed as planned in the final years of the project.
1. Reduction of inorganic arsenic (iAs) concentration during cooking of rice. Rice is the staple food for half of the world’s population, but it also contains a much higher concentration of iAs, a Class-1 carcinogen, than other grains or vegetables. ARS researchers at Wyndmoor, Pennsylvania, developed an effective procedure to reduce iAs levels by first soaking 1-part rice at 80 degrees C in 10 parts water, which is discarded after 10 minutes, and then cooking the rice in 2 parts water as usual in East Asia. On average, a 40% reduction in iAs concentration was achieved by this method due to the higher solubility of iAs in the hot water that also contains the starchy gelatinous components from the rice. This pre-soaking method is easily implemented by the public to reduce chronic arsenic exposure using common cooking practices. Those who follow this simple approach will cut their risk of cancer, which could impact billions of people worldwide if this information is widely disseminated.
2. Development of hydride generation - cryogenic trapping - inductively-coupled plasma - mass spectrometry (HG-CT-ICP-MS) for analysis of inorganic arsenic (iAs). ICP-MS is the benchmark technique for elemental analysis due to its high sensitivity and wide dynamic range, but the toxic iAs species must first be separated from the less toxic metalorganic forms of arsenic prior to analysis of samples. Conventional methods of iAs separation are slow and use expensive equipment and large amounts of reagents. Cryogenic trapping advantageously uses temperature rather than chemical reagents to speciate arsenic due to boiling point differences. ARS researchers at Wyndmoor, Pennsylvania, developed HG-CT-ICP-MS for the first time in analytical chemistry to analyze iAs in different foods. This environmentally green system reduces costs by requiring less instrumentation and reagents, including argon gas for ICP-MS, and greatly increases sample throughput. The cryotrapping device for this approach has been patented by ARS and is available for possible commercialization and widespread implementation.
3. Development and validation of a method for analysis of >300 pesticides and environmental contaminants in catfish. Catfish is one of the most consumed freshwater fish in the USA, valued for its nutritional benefits, but it is a bottom feeder, which causes concerns about potential accumulation of chemical contaminants. ARS scientists at Wyndmoor, Pennsylvania, developed and validated a simple, fast and efficient analytical method for the analysis of 302 pesticides and environmental contaminants in catfish muscle. The method was successfully validated at and below U.S. regulatory levels of concern and applied to the analysis of fish from the market. The method is being implemented by the USDA Food Safety and Inspection Service (FSIS) for routine monitoring of contaminants in catfish in the U.S. National Residue Program. The new method provides high sample throughput, wide monitoring scope and reduced cost of analysis.
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