RESUMO
BACKGROUND: The presence of veterinary drug residues in food-producing animals and animal products is regulated through the enforcement of maximum residue limits (MRLs). To answer the need of the food sector to monitor these substances in a wide range of food commodities, stakeholders at AOAC identified the need for a reliable confirmatory screening method. Such qualitative approach is required for compliance checking and to support product release in manufacturing. OBJECTIVE: Data were collected from 5 independent laboratories that applied the AOAC Official First Action Method AOAC 2020.04 to demonstrate adequate performance under reproducibility conditions. Probability of Detection (POD) was calculated in blank test samples and test samples spiked at the Screening Target Concentration (STC) level, with the objective to achieve PODs ≤ 10% and ≥ 90%, respectively. Additionally, the effectiveness of the screening method was assessed through participation to 92 proficiency test samples. METHODS: Four streams were optimized to screen for 152 veterinary drug residues by LC-MS/MS in a wide variety of food commodities including milk-based ingredients and related products (e.g., milk fractions, infant formula, infant cereals and baby foods), meat- and fish-based ingredients and related products (fresh, powdered, cooked, infant cereals and baby foods) and other ingredients such as eggs, animal fat and animal byproducts. The four streams covered 105 antibiotic residues, anti-inflammatory and antiparasitic agents (Stream A); 23 Beta-lactams (Stream B); 14 Aminoglycosides (Stream C) and 10 Tetracyclines (Stream D). RESULTS: The multi-laboratory validation led to PODs at the STC ≥ 94% and PODs in the blank ≤ 9%. Further application of the multi-laboratory validated method to 92 proficiency tests provided more than 99% satisfactory submitted results (n = 784). CONCLUSION: The inter-laboratory reproducibility determined for this method met the acceptance criteria defined in AOAC SMPR 2018.010. HIGHLIGHTS: AOAC has approved the method for Final Action Status.
RESUMO
Optimization and validation of a multi-mycotoxin method by LC-MS/MS is presented. The method covers the EU-regulated mycotoxins (aflatoxins, fumonisins, ochratoxin A, deoxynivalenol, zearalenone, T-2 and HT-2), as well as nivalenol and 3- and 15-acetyldeoxynivalenol for analysis of cereals, cocoa, oil, spices, infant formula, coffee and nuts. The proposed procedure combines two clean-up strategies: First, a generic preparation suitable for all mycotoxins based on the QuEChERS (for quick, easy, cheap, effective, rugged and safe) protocol. Second, a specific clean-up devoted to aflatoxins and ochratoxin A using immunoaffinity column (IAC) clean-up. Positive identification of mycotoxins in matrix was conducted according to the confirmation criteria defined in EU Commission Decision 2002/657/EC while quantification was performed by isotopic dilution using (13)C-labeled mycotoxins as internal standards. Limits of quantification were at or below the maximum levels set in the EC/1886/2006 document for all mycotoxin/matrix combinations under regulation. In particular, the inclusion of an IAC step allowed achieving LOQs as low as 0.05 and 0.25µg/kg in cereals for aflatoxins and ochratoxin A, respectively. Other performance parameters like linearity [(r)(2)>0.99], recovery [71-118%], precision [(RSDr and RSDiR)<33%], and trueness [78-117%] were all compliant with the analytical requirements stipulated in the CEN/TR/16059 document. Method ruggedness was proved by a verification process conducted by another laboratory.
