The USDA Food Safety and Inspection Services (FSIS) has developed a new method to quantify chemical residues using beef muscle samples and modern chemistry instrumentation. The agency’s laboratory system plans to implement the new quantitative method for veterinary drug residue analysis in bovine muscle samples on October 1, 2023. The method, “Quantitation of Animal Drug Residues by High-Resolution, Accurate-Mass Liquid Chromatography Mass Spectrometry (HRAM LC-MS)” (CLG-MRQ1), has the ability to:

• Quantitate multiple veterinary drug residue amounts simultaneously in a single analysis with high mass accuracy.
• Quantitate several veterinary drugs that were previously difficult to measure.
• Archive several single analyte or specific drug class quantitation methods that use older technology.
• Archive traditional residue bioassay for several analytes.
• Align detection limits with established drug residue tolerances.
• Decrease time to result for presumptive positive residues.

In addition to this change, FSIS has recently updated three methods that will be posted to the new Chemical Laboratory Guidebook no late than September 30, 2023. They include: Quantitation of Salt (CLG-SLT); Quantitation of Fat (CLG-FAT); and Screening, Quantitation, and Confirmation of Beta-Agonists by UHPLC-MS-MS (CLG-AGON1).