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Listen to this siteTuesday 15 August 2006
This research project aims to assess two sample preparation techniques for nuts to see if they resulted in significant differences in the variability of aflatoxin levels.
Study Duration : February 2000 till July 2000
Contractor : Central Sciences Laboratory
The introduction of European legislation and a supporting directive describing sampling plans and analysis for aflatoxins stimulated debate on the most suitable approach for ensuring sample homogeneity before analysis.
The mean aflatoxin concentration determined in the samples was used to assess if the addition of water during homogenisation had an impact on the performance of the analytical method used, i.e. was there a significant difference in aflatoxin determined between the preparation methods? A secondary objective was to assess whether the addition of water had any effect on the performance of the proposed CEN method for aflatoxin detection.
Five Brazil nut samples were thoroughly mixed by dry mixing and split into two equal portions. For each, one portion was further mixed, the other portion slurried with water in the ratio 5:4 (nut:water). For two of the five samples two analysis methods were performed: the CSL in-house method and a validated method (proposed CEN method).
The introduction of European legislation and a supporting directive describing sampling plans and analysis for aflatoxins has stimulated debate on the most suitable approach for ensuring sample homogeneity before analysis. The CEN Working Group on Biotoxins has discussed a document which proposes that preparation of a slurry with water could be used for all samples. Previously, dry mixing has been used by laboratories for products such as nuts and spices, while slurrying has been used for dried fruit. The objective of this study was to assess two sample preparation techniques for nuts, namely tumble-mixing dry ground material and slurrying with water, to determine if these resulted in significant differences in the overall variability of aflatoxin.
Statistical analysis to measure differences in variability found no significant differences between the sample preparation techniques or the analysis methods. T-tests found significant differences in the aflatoxin concentrations measured by the two methods, but these were not consistent in the direction of the difference; however, higher residues were found more frequently in samples that had been slurried with water. The addition of water in the ratio used for this study did not affect the performance of the proposed CEN method.
The final report is available from the Agency's Information Centre.
To obtain a copy, please contact the Enquiry Desk, Information Services, Food Standards Agency (tel: 020 7276 8181/8182 or email: infocentre@foodstandards.gsi.gov.uk )
Contact
: For any enquiries concerning this research project, please contact the relevant programme contact or email:
science@foodstandards.gsi.gov.uk
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