As the distribution of mycotoxins is generally non-homogeneous, samples shall be prepared, and especially homogenised, with extreme care.
The complete sample as received by the laboratory shall be homogenized, in case the homogenisation is performed by the laboratory.
For the analysis of aflatoxins, daylight should be excluded as much as possible during the procedure, since aflatoxin gradually breaks down under the influence of ultra-violet light.
The limits fixed for aflatoxins in Regulation (EC) No 466/2001 apply to the edible part. The level of aflatoxins in the edible part can be determined by:
samples of nuts ‘in shell’ can be shelled and the level of aflatoxins is determined in the edible part.
the nuts ‘in shell’ can be taken through the sample preparation procedure. The method of sampling and analysis shall estimate the weight of nut kernel in the aggregate sample. The weight of nut kernel in the aggregate sample shall be estimated after establishing a suitable factor for the proportion of nut shell to nut kernel in whole nuts. This proportion is used to ascertain the amount of kernel in the bulk sample taken through the sample preparation and method of analysis.
Approximately 100 whole nuts shall be taken at random separately from the lot or shall be put aside from each aggregate sample. The ratio may, for each laboratory sample, be obtained by weighing the whole nuts, shelling and re-weighing the shell and kernel portions.
However, the proportion of shell to kernel may be established by the laboratory from a number of samples and so can be assumed for future analytical work. But if a particular laboratory sample is found to be in contravention of any limit, the proportion shall be determined for that sample using the approximately 100 nuts that have been set aside.