Detection of frozen-thawed beef, pork and chicken meat

Thawed meat isusually oflower quality and less expensive than chilled meat, which some dishonest people may exploit byfraudulently marketing itaschilled. This study focused onmethods for detecting and distinguishing frozen meat from chilled meat. The activity ofthe enzyme aconitase inthe eluate was determined, and the mineral cations (Na+, K+, Mg2+) aswell asthe concentrations oforganic acids (acetic, citric, and lactic) were analysed inchilled and thawed meat stored for 7, 14, and 150 days at−18 C. After 150 days ofstorage, aconitase activity increased from 47.2±7.2 U·L–1 to395.3±59.2U·L–1 inpork, from 45.8±11.5U·L–1 to133.3±31.8U·L–1 inbeef, and from 17.2±8.6U·L–1 to143.6±41.5U·L–1 inchicken. The mineral content decreased during storage inmeat samples, especially Na+ and K+ cations (P<0.05). The results for organic acids were less conclusive. Principal component analysis (PCA) of the data confirmed a clear separation between chilled and thawed meat for all species, with a high variability of nearly 72%.