Hypersensitive colorimetric assay based on microbial inhibition for the detection of multiple antibiotics

Antibiotic residues resulting from antibiotic abuse pose a progressive concern in the environmental ecology and public health, requiring efficacious analytical assessment and monitoring strategies. Herein, a novel label-free colorimetric assay based on the spore growth inhibition of GeoBacillus stearothermophilus (G. stearothermophilus) was proposed to determine trace multiple antibiotics. The lyophilized spores demonstrated a satisfactory survival rate of 85.47 % and were utilized as indicator bacteria. Innovative sensitizers combined with pH indicator bromocresol violet facilitated the sensitivity of the sensing platform, which had favorable qualitative detection limits. Furthermore, by employing compound cold-water gel as an alternative culture component, the colorimetric assay displayed excellent anti-interference and reliability in analyzing multiple antibiotics in 2.5 h. Thus, the proposed colorimetric system provides a valuable perspective for constructing microorganism-based analytical strategies for the simultaneous detection of multiple antibiotics in milk samples, which is potentially applicable to evaluating the safety of milk-derived foods.