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Determination of aflatoxin risk components for in-shell Brazil nuts.

A study was conducted on the risk from aflatoxins associated with the kernels and shells of Brazil nuts. Samples were collected from processing plants in Amazonia, Brazil. A total of 54 test samples (40u2009kg) were taken from 13 in-shell Brazil nut lots ready for market. Each in-shell sample was shelled and the kernels and shells were sorted in five fractions: good kernels, rotten kernels, good shells with kernel residue, good shells without kernel residue, and rotten shells, and analysed for aflatoxins. The kernelu2009:u2009shell ratio mass (w/w) was 50.2/49.8%. The Brazil nut shell was found to be contaminated with aflatoxin. Rotten nuts were found to be a high-risk fraction for aflatoxin in in-shell Brazil nut lots. Rotten nuts contributed only 4.2% of the sample mass (kg), but contributed 76.6% of the total aflatoxin mass (µg) in the in-shell test sample. The highest correlations were found between the aflatoxin concentration in in-shell Brazil nuts samples and the aflatoxin concentration in all defective fractions (R 2u2009=u20090.97). The aflatoxin mass of all defective fractions (R 2u2009=u20090.90) as well as that of the rotten nut (R 2u2009=u20090.88) were also strongly correlated with the aflatoxin concentration of the in-shell test samples. Process factors of 0.17, 0.16 and 0.24 were respectively calculated to estimate the aflatoxin concentration in the good kernels (edible) and good nuts by measuring the aflatoxin concentration in the in-shell test sample and in all kernels, respectively.

Design of a sampling plan to detect ochratoxin A in green coffee

The establishment of maximum limits for ochratoxin A (OTA) in coffee by importing countries requires that coffee-producing countries develop scientifically based sampling plans to assess OTA contents in lots of green coffee before coffee enters the market thus reducing consumer exposure to OTA, minimizing the number of lots rejected, and reducing financial loss for producing countries. A study was carried out to design an official sampling plan to determine OTA in green coffee produced in Brazil. Twenty-five lots of green coffee (type 7 – approximately 160 defects) were sampled according to an experimental protocol where 16 test samples were taken from each lot (total of 16u2009kg) resulting in a total of 800 OTA analyses. The total, sampling, sample preparation, and analytical variances were 10.75 (CVu2009=u200965.6%), 7.80 (CVu2009=u200955.8%), 2.84 (CVu2009=u200933.7%), and 0.11 (CVu2009=u20096.6%), respectively, assuming a regulatory limit of 5u2009µgu2009kg−1 OTA and using a 1u2009kg sample, Romer RAS mill, 25u2009g sub-samples, and high performance liquid chromatography. The observed OTA distribution among the 16 OTA sample results was compared to several theoretical distributions. The 2 parameter-log normal distribution was selected to model OTA test results for green coffee as it gave the best fit across all 25 lot distributions. Specific computer software was developed using the variance and distribution information to predict the probability of accepting or rejecting coffee lots at specific OTA concentrations. The acceptation probability was used to compute an operating characteristic (OC) curve specific to a sampling plan design. The OC curve was used to predict the rejection of good lots (sellers’ or exporters’ risk) and the acceptance of bad lots (buyers’ or importers’ risk).

Number of export almond lots rejected in the EU due to USA sampling plans and aflatoxin contamination levels among lots tested

In March 2010, the European Union (EU) modified their aflatoxin limits and sampling plans for almonds, pistachios, and hazelnuts to closely resemble that developed by Codex in 2008. To assist the USA almond industry evaluate how to modify their aflatoxin sampling plan to minimise USA lots rejected by the EU at import, studies were conducted to: (a) develop a model to predict the number of USA almond lots rejected at origin and at destination by various Codex style aflatoxin-sampling plans used by the USA where accept/reject limits vary from EU limits of 8 ng/g aflatoxin B1 / 10 ng/g total aflatoxins (AFT) to 8, 6, 4, 2, and 0.5 ng/g AFT; (b) determine the effect of the level of aflatoxin contamination among lots tested in the USA on the number of lots accepted and rejected at origin and at destination; and (c) develop a method based upon lots rejected in the USA to predict the lots rejected several months later in the EU. For a given USA crop contamination level, as the accept/reject limits of the USA sam...