Comparison of risk-based versus random sampling in the monitoring of antimicrobial residues in Danish finishing pigs

The HPLC LC-MS/MS method detected the same number of cases compared to the bioassay when kidney was used as matrix. HPLC LC-MS/MS has a higher sensitivity when used on muscle but it is almost twice as costly as the bioassay. Risk-based sampling resulted in detection of more residue cases with higher cost-effectiveness than random monitoring. Sampling 7500 HR pigs and 5000 LR pigs resulted in the most cost-effective monitoring among the alternative scenarios. The associated costs would increase by 4%. A scenario involving testing of 5000 HR and 5000 LR animals would result in slightly fewer positives, but 17% savings in costs. The advantages of using HPLC LC-MS/MS compared to the bioassay are a fast response and a high sensitivity for all relevant substances used in pigs. The Danish abattoir companies have implemented a risk-based monitoring similar to the above per January 2016.