Ensuring the reliability of brominated flame retardant data on food and feed occurrence through harmonised analytical criteria and proficiency testing.

The volume of occurrence data on food and animal feed contaminants such as polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecanes (HBCDDs) is slowly increasing as more laboratories develop analytical capability. This data allows an evaluation of current background levels in different countries and regions and is also useful for estimating the health risk through dietary exposure and as evidence for the formulation of future control strategies. Existing data varies in the number of analytes reported and the quality measures applied. In order to ensure reliability and comparability, guidance on analytical criteria such as precision and trueness, limits of quantitation, recovery, positive identification, etc. is provided. These parameters are based on several years of collective experience and allow validation and regular quality control of analysis of individual PBDE congeners and HBCDD stereoisomers. The criteria-based approach also allows laboratories the flexibility to use different analytical methodologies and techniques for generating data. The effectiveness of this approach has been demonstrated by a successful proficiency testing scheme that has been used for a number of years and has attracted an increasing number of participants. The majority of participating laboratories (>80%) have been able to demonstrate performance within the 95% confidence interval (│z-score│≤ 2) and a further 10% of laboratories demonstrated performance with a z-score of (2 <│z-score│< 3). The combined support of these guidance criteria backed by successful proficiency testing will ensure the reliability and comparability of results, in particular, to refine risk assessments and to help the formulation of regulatory policy.