MS most commonly stands for mass spectrometry, the analytical technique that identifies and quantifies compounds by measuring the mass-to-charge ratio of their ions. It is the backbone of modern food analysis: paired with gas or liquid chromatography, it detects pesticide residues, mycotoxins, allergens, veterinary drugs, and adulterants at trace levels, verifies authenticity, and profiles flavors and contaminants. Food laboratories rely on MS methods for regulatory compliance testing, and results underpin enforcement actions, product recalls, and import rejections. The abbreviation can also mean other things in context, but in food laboratories mass spectrometry is the default meaning.