Location: Microbial and Chemical Food Safety
2020 Annual Report
Objectives
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.
Approach
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 Report
Progress was made in all objectives, and the project is progressing according to schedule, except for Objective 6 which will be ended due to the resignation on 9/30/18 of the scientist leading investigations on antimicrobial resistance and abolishment of the position. Analytical methods using mass spectrometry for detection of biomarkers indicating antimicrobial resistance were developed, but the planned correlation with samples containing antibiotic residues could not be conducted. Otherwise, Objectives 1A, 1B, 2, 3, 4, and 5 are fully met. The covid-19 pandemic and closure of the lab in March 2020 for more than 3 months delayed the planned monitoring of samples for pesticides, veterinary drugs, and environmental contaminants. Fortunately, the food packaging leaching study had been completed before the lab closure. A gas chromatograph – orbital ion trap mass spectrometer has been installed through a material transfer research agreement.
Development of a low-volume membrane gas-liquid separator (MGLS) for hydride generation (HG) in analysis of lead and cadmium. Simultaneous analysis of lead (Pb) and cadmium (Cd) in a variety of sample types, including foods, at the same time as other metals that require HG in their analysis, such as inorganic arsenic (iAs) is challenging proposition. ARS scientists in Wyndmoor, Pennsylvania, demonstrated the feasibility of HG for analysis of Pb and Cd by developing a MGLS using a 1.9 mm outer diameter, 1 µm porous polytetrafluoroethylene (PTFE) tubular membrane. The MGLS has a low intrinsic volume to minimize contact time and hence increases interaction between hydride products and sample solution. The design has an additional advantage to minimize polyatomic interferences, which is especially useful when inductively -coupled plasma – mass spectrometry (ICP-MS) is used for detection. The MGLS is a key step in the development of a multi-element method that includes Cd, Pb, and iAs in the same analysis of food samples.
Accomplishments
1. Development of the “quick, easy, cheap, effective, rugged, safe, efficient, and robust” (QuEChERSER) mega-method to analyze pesticides, veterinary drugs, and environmental contaminants in foods. In 2003, the QuEChERS approach to sample preparation was introduced for pesticide residue analysis in foods, which has become the primary method used worldwide in the application, but instrumentation and technology has continued to improve in the past 17 years, creating a need to update the QuEChERS method. Using modern tools of mass spectrometry for detection, ARS scientists in Wyndmoor, Pennsylvania, expanded analytical scope to include veterinary drugs in the same method, further streamlined the steps, and added an automated cleanup technique conducted in parallel with analysis. So far, the new QuEChERSER mega-method has been validated for up to 349 diverse analytes in fish, bovine, caprine, and ovine muscle, hemp pruducts, and fruits and vegetables. QuEChERSER is expected to eventually supplant QuEChERS as the primary method for monitoring a wide array of chemical contaminants in foods.
2. Development of a fast screening method for the analysis of pesticides and mycotoxins in food and feed. Fast and simple screening methods are needed for the analysis of harmful contaminants in food and feed samples in regulatory testing. Currently, the fastest instrumental analysis takes at least 10 minutes by liquid chromatography-mass spectrometry. ARS scientists in Wyndmoor, Pennsylvania, in collaboration with scientists from Wageningen Food Research in the Netherlands, developed a 2-minute analysis using flow injection coupled with mass spectrometry for fast screening of 12 pesticides and 7 mycotoxins in complex samples of grains and animal feed. The developed approach allows rapid screening of pesticides and mycotoxins at their respective U.S. tolerances and the European Union (EU) maximum residue limits. Compared to existing methods, the new method provides simplicity, higher throughput, lower cost, and efficient use of high-end instrumentation.
3. Accumulation of contaminants in fish influenced by snowmelt and municipal effluent discharge. ARS scientists in Wyndmoor, Pennsylvania, in collaboration with scientists from Baylor University in Waco, Texas, studied the accumulation of pesticides and environmental contaminants in fish collected from East Canyon Creek, Utah. The creek is in a semi-arid ecosystem fed by snowmelt in spring and municipal effluent discharge in the summer and fall. Fish samples (brown trout and mottled sculpin) collected in four seasons at incremental distances downstream of the effluent discharge showed accumulation of 18 contaminants at low ng/g levels. The seasons did not make a difference. The highest levels of certain banned flame retardants (polybrominated diphenyl ethers) were found in fish collected close to the effluent discharge.
Review Publications
Fialkov, A.B., Lehotay, S.J., Amirav, A. 2019. Less than 1 minute low-pressure gas chromatography - mass spectrometry. Journal of Chromatography A. 1612:460691. https://doi.org/10.1016/j.chroma.2019.460691.
Lehotay, S.J., Lightfield, A.R. 2020. Extract-and-inject analysis of veterinary drug residues in catfish and ready-to-eat meats by ultrahigh-performance liquid chromatography – tandem mass spectrometry. Journal of AOAC International. 103(2): 584-606. https://doi.org/10.1093/jaoacint/qsz036.
Lehotay, S.J., Michlig, N., Lightfield, A.R. 2020. Assessment of test portion sizes after sample comminution with liquid nitrogen in the high-throughput analysis of pesticide residues in fruits and vegetables. Journal of Agricultural and Food Chemistry. 68:1468-1479. https://doi.org/10.1021/acs.jafc.9b07685.
Chen, G., Lai, B., Chen, T., Mao, X. 2020. Brief soaking at above-gelatinization temperature reduces inorganic arsenic in cooked rice. Cereal Chemistry. https://doi.org/10.1002/cche.10304.
Monteiro, S.H., Lehotay, S.J., Sapozhnikova, Y.V., Ninga, E., Lightfield, A.R. 2020. High-throughput mega-method for the analysis of pesticides, veterinary drugs, and environmental contaminants by ultra-high-performance liquid chromatography-tandem mass spectrometry and robotic mini-solid-phase extraction cleanup + low-pressure gas chromatography-tandem mass spectrometry, Part 1: Beef. Journal of Agricultural and Food Chemistry. 69:1169-1174. https://doi.org/10.1021/acs.jafc.0c00710?ref=pdf
Sapozhnikova, Y.V., Salamova, A., Haddad, S., Burket, S.R., Luers, M., Brooks, B. 2020. Spatial and seasonal occurrence of pesticides and environmental contaminants in fish tissues influenced by snowmelt and municipal effluent discharge. Science of the Total Environment. https://doi.org/10.1016/j.scitotenv.2020.140222.
Roussey, M., Lehotay, S.J., Pollaehne, J. 2019. Cryogenic sample processing with liquid nitrogen for effective and efficient monitoring of pesticide residues in foods and feeds. Journal of Agricultural and Food Chemistry. 67(33):9203-9209. https://doi.org/10.1021/acs.jafc.9b04006.
