Optimizing sample preparation for homogeneous mycotoxin distribution in official control analyses

Background. The distribution of mycotoxins within cereal batches is highly heterogeneous. Therefore, to obtain representative samples and accurate analytical results, sample homogenization is a critical preparatory step.
Objective. To provide reliable and standardized instructions for preparing an aggregate grain sample within official control framework, four different homogenization procedures were evaluated. The comparison considered variability in mycotoxin distribution, workload, and time constraints.
Methods. The study was conducted on four aggregate samples, each weighing 10 kg, obtained from a maize grain batch according to regulatory provisions of Regulation (EU) 2023/2782. Analytical variability of aflatoxin (B1 and B2) and fumonisin (B1 and B2) was measured.
Results. The contamination levels in each pooled sample and the degree of homogeneity among the procedures were assessed and compared using the relative standard deviation of repeatability (RSDr) as acceptability criterion.
Conclusions. The procedures involving fine grinding (particle size <0.5 mm) and aqueous slurry preparation yielded the best results in terms of homogeneity.