Infrared spectroscopy in short: a powerful analytical technique identifying samples by their absorption of infrared-wavelength light. Because different molecular bonds absorb at characteristic wavelengths, the resulting spectrum fingerprints the material. Food laboratories use it — especially near-infrared versions — for rapid, non-destructive measurement of moisture, fat, protein, and adulterants in grains, dairy, and meat. No reagents or sample destruction are needed, so testing is both fast and cheap. Chemometric models translate its spectra into the numbers that quality managers use.