Construction of a Sensing Platform Integrated with a CRISPR/Cas12a-Triggered Colorimetric Strategy for the Quantitative Detection of Meat Freshness

Monitoring microbial determinants, such as Pseudomonas spp., is thus essential for assessing meat freshness. Here, a novel colorimetric sensing platform based on magnetic enzyme-labeled nanoparticles combined with clustered regularly interspaced short palindromic repeats (CRISPR)/Cas12a without nucleic acid molecule preamplification was developed for detecting meat freshness. Under optimal conditions, a high-specificity crRNA was systematically verified, and the colorimetric sensor could accurately quantify Pseudomonas spp. loads with levels ranging from 1 × 10^3.7 to 1 × 10^8.7 CFU/mL, with a color change from colorless to yellow. A smart colorimetric platform, including a self-designed image acquisition device and self-programmed image analysis software, was developed and applied to the integrated determination of meat freshness by using the B-value in the RGB channel. The platform has been applied to both consumers and producers and has been validated by 48 actual samples of chilled meat. These findings provide new insights into the exploration of reliable tools for monitoring meat freshness.