Ultra-rapid photosensitive colorimetric card for meat freshness detection based on Rose Bengal-catalyzed photosensitive oxidation

Rapid and reliable quantification of meat freshness is crucial for consumer health and food safety. In this study, two simple and portable photosensitive colorimetric cards were fabricated for rapid on-site detection of meat freshness. The colorimetric cards were prepared by dispersing Rose Bengal (RB) into sodium acetate-acetic acid and sodium citrate-citric acid buffer systems containing 3,3′,5,5′-tetramethylbenzidine (TMB) and fixed on filter paper, respectively. The hue of the colorimetric cards was intimately correlated with the amount of volatile base nitrogen absorbed from meat, by which the quality of the meat can be visualized qualitatively. Correlation analysis of total volatile basic nitrogen (TVB-N), red: blue ratio (R/B), total color difference (ΔE), and response sensitivity (S%) demonstrated the accuracy of the proposed colorimetric cards. Principal component analysis (PCA) revealed that the first two principal components of the photosensitive colorimetric cards explained 95.4 %, 93.2 %, 92.9 %, and 87.8 % of the variance of sodium acetate-acetate colorimetric card, and 73 %, 87.9 %, 87.1 %, and 92 % of sodium citrate-citric card, respectively, which allowed for a clear differentiation of meat freshness including freshness, sub-freshness, and spoilage. The prepared photosensitive colorimetric cards can accurately reflect meat quality within 4 min. The proposed colorimetric cards are expected to be a prospective universal platform for on-site accurate quantification of meat freshness.