A review of sampling plans and collaboratively studied methods of analysis for aflatoxins

Aflatoxins are the only food contaminants being monitored routinely on an international scale with methods operating at the order of magnitude of 10 mug/kg. At this concentration level, methods of analysis which can achieve coefficients of variation of 30-40% with recoveries of 70% or greater in interlaboratory collaborative studies can be considered eligible for referee status. In most cases, sample reproducibility is the variable limiting the reliability of methods of analysis. The inherent uncertainty of the identity of chromatographically separated entities requires the application of confirmatory tests to verify that the characteristic measured results from the presence of aflatoxin. The methods are also inoperable without a verification of the identity, purity, and concentration of the reference standards used. Screening methods which reliably eliminate negative samples from further consideration are indispensible for the practical operation of monitoring programs.