Technical recommendations for the prevention and control of aflatoxins in the Brazil nut production chain

The present work was carried out within the framework of the Safenut project (http://stdf-safenutproject.com/) financed by the Standards and Trade Development Facility (STDF 114 -http://www.standardsfacility.org/). It aimed at identifying the critical points and factors for fungal growth and aflatoxin production along the Brazil nut production chain, and formulates technical recommendations of good practices for preventing and controlling toxin production. For that purpose, samples of Brazil nuts in shell were collected at different points of two production chains selected in each of the main Brazil nut producing and exporting states of the Amazon region in Brazil, Acre and Pará. Representative sampling was performed according to Commission Regulation (EC) 401/2006 and sample water activity, aflatoxigenic moulds and aflatoxins were analyzed by using a Pawkit meter, AFPA agar and HPLC methodology, respectively. The results showed that the practices currently used in the Brazil nut production chain, based on the existing manual of good practices, are not effective for aflatoxin control in unshelled nuts (levels above the European limits). The critical points are the drying step and storage time in the extractivist community. The techniques used - sun drying and/or natural air circulation - are not effective to dry nuts at a safe moisture level (i.e. water activity below 0.7). On the contrary, the moisture contents reached are often around the optimal range for aflatoxin production. This results in an increase of aflatoxin content during storage over several months. The Brazil nut lots delivered at the processing industries are already contaminated with high levels of aflatoxins, and the selection processes used in these industries are not effective to remove the contaminated unshelled nuts (nuts must first be broken). Based on these results, recommendations were formulated to revise the existing manual of good practices, in particular the Codex Code of Practice for the Prevention and Reduction of Aflatoxin Contamination in Tree Nuts (CAC/RCP 59 - 2005, REV. 1-2006). (Texte intégral