Although the administration of β-agonists as growth-promoting agents in food-producing animals is banned in many countries due to concerns over human health, ractopamine is authorized for some animal production in a limited number of countries. As these countries have significant export trade of meat to countries where β-agonists are banned, split production systems with associated certification programs have been put in place. Countries where use is approved (e.g. USA and Canada) have maximum residue limits (MRLs) or tolerances for ractopamine, whereas those that have banned meat products containing β agonists have to take an alternative approach. As no Minimum Required Performance Limits (MRPLs) were set for β-agonists, the EU relies on Recommended Concentrations to indicate required performance of analytical methods used for those substances. In contrast, Russia, also with a zero tolerance policy, established an action level for ractopamine in imported consignments of meat one hundred times lower than the Codex MRL.
Monitoring compliance with these limits requires the use of highly sensitive and selective analytical methodology based upon liquid chromatography-tandem mass spectrometry (LC-MS/MS). Examples of performance are given for the analysis of 16 β-agonists in various animal target tissues (e.g. liver), edible products (e.g. muscle) and urine collected from animals on the farm. As the frequency of detection of residues is low, samples are screened using an adequate level of quality control including the use of stable isotope analogues as surrogates to monitor sample-to-sample variability in matrix effects. Any suspect positives are re-analyzed with a suitable confirmatory method.