Antibiotics in milk: Validation of analytical methodologies for ensuring food safety

Contamination of milk with antibiotics poses a significant threat to food safety and public health. To address this issue, it is crucial to develop and validate accurate analytical methodologies that can reliably detect and quantify the presence of antibiotics in milk. This work aimed to implement an analytical methodology by UHPLC-QTRAP-MS/MS for the determination of 88 antibiotics belonging to ten pharmacological classes in milk. The method showed high selectivity and sensitivity, with linearities above 0.95 obtained through a matrix-matched calibration approach. Decision limit (CCα) values ranged from 1.3 to 239.4 μg.kg -1 . Limits of detection (LOD) and limits of quantification (LOQ) were determined with the highest values of 22.33 μg.kg -1 and 44.85 μg.kg -1 , respectively. Repeatability and reproducibility were below 21.8 and 23.2%, and recovery ranged between 80.9 and 118.9%. Application to real samples from local markets demonstrated the presence of macrolides and sulphonamides, though concentrations were below the regulated limits. These results showed the importance of developing and validating new analytical strategies to ensure the safety of dairy products. • Antibiotics in milk threaten food safety by fostering antibiotic resistance. • A UHPLC-QTRAP-MS/MS method detects 88 antibiotics in milk with high precision. • Method validation met EU 2021/808 standards, showing sensitivity and selectivity. • Real samples revealed antibiotic residues, all within regulated safety limits.