Short for thiobarbituric acid reactive substances (TBARS) — the collective name for malondialdehyde (malonaldehyde) plus the other compounds produced when lipids oxidize, quantified through their reaction with thiobarbituric acid to give ‘TBA values’. Results are reported as milligrams of malonaldehyde equivalents per kilogram of sample, and the TBARS assay is a standard chemical index of oxidative rancidity in meats, fish, oils, and fried snacks. Because laboratories vary the test — heating times, reagents, extraction procedures — values from different studies cannot be compared naively; consistent methodology within a quality programme is essential for meaningful trend data.