Sampling cottonseed lots for aflatoxin contamination

Velasco, James; Whitaker, T. B.; Whitten, M. E.

doi:10.1007/bf02672168

Cited by 19 publications

(9 citation statements)

References 4 publications

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“…Sampling variance accounts for the majority of the total variance, followed by sample preparation and analytical variance. This is consistent with what has been observed with other mycotoxins and other commodities ( Johansson et al 2000b;FAO 1993;Velasco et al 1975;Whitaker et al 1976Whitaker et al , 1994aWhitaker et al , 2000Whitaker et al , 1998Whitaker et al , 1974). For small sample sizes, sampling is usually the largest source of error.…”

Section: Total Variancesupporting

confidence: 91%

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

Vargas

Whitaker

Santos

et al. 2006

Food Additives and Contaminants

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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 16 kg) resulting in a total of 800 OTA analyses. The total, sampling, sample preparation, and analytical variances were 10.75 (CV = 65.6%), 7.80 (CV = 55.8%), 2.84 (CV = 33.7%), and 0.11 (CV = 6.6%), respectively, assuming a regulatory limit of 5 microg kg(-1) OTA and using a 1 kg sample, Romer RAS mill, 25 g 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).

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Section: Total Variancesupporting

confidence: 91%

“…Although methods have been developed to evaluate and design sampling plans for aflatoxins ( Johansson et al 2000b;FAO 1993;Velasco et al 1975;Whitaker et al 1976Whitaker et al , 1994aCODEX 2001), deoxynivalenol (Whitaker et al 2000), and fumonisins , none of them were designed for OTA in coffee. The objectives of this study were:…”

Section: Introductionmentioning

confidence: 98%

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

Vargas

Whitaker

Santos

et al. 2006

Food Additives and Contaminants

Self Cite

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“…Three distributions may be used to describe the variability of test results ~ about the lot concentration p: (a) distribution of sample concentrations xs about the lot concentration p, (b) distribution of subsample concentration Xss about the sample concentration Ps, and (c) distribution of analytical determinations Xa about the subsample concentration Pss. Previous studies on peanuts and cottonseed (1,2,5) have indicated that the sample and subsample distributions can be simulated best with a skewed-type probability distribution function, whereas the analytical distribution tends to be more nearly normal.…”

Section: Theoretical Modelmentioning

confidence: 99%

“…The concentration of aflatoxin in cottonseed lots is estimated by analyzing samples taken from each lot. The estimations are difficult to make because of the large variability associated with replicated test results on the contaminated lot (1,2). Typical steps taken to estimate the aflatoxin concentration in cottonseed lots are shown in Figure 1.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of cottonseed aflatoxin testing programs

Whitaker

Whitten

1977

J Americ Oil Chem Soc

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“…Thus, dry and slurry grinding have been investigated to accurately estimate mycotoxin levels in various matrices using different types of mills (Dickens and Satterwhite 1969;Whitaker et al 1974Whitaker et al , 1980Velasco and Whitaker 1975;Velasco and Morris 1976;Dorner and Cole 1993;Calori-Dominges et al 2000).…”

Section: Introductionmentioning

confidence: 98%

Comparison of homogenization techniques and incidence of aflatoxin contamination in dried figs for export

Bircan

2009

Food Additives and Contaminants: Part B

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To determine differences in mean aflatoxin contamination and subsample variance from dry and slurry homogenizations, 10 kg of six different, naturally contaminated dried fig samples were collected from various exporting companies in accordance with the EU Commission Directive. The samples were first dry-mixed for 5 min using a blender and sub-sampled seven times; the remainder was slurry homogenized (1 : 1, v/v) and sub-sampled seven times. Aflatoxin B1 and total aflatoxin levels were recorded and coefficient of variations (CV) computed for all sub-samples. Only a small reduction in sub-sample variations, indicated by the lower CV values, and slight differences in mean aflatoxin B1 and total aflatoxin levels were observed when slurry homogenization was applied. Therefore, 7326 dried figs, destined for export from Turkey to the EU and collected during the 2008 crop year, were dry-homogenized and tested for aflatoxins (B1, B2, G1 and G2) by immunoaffinity column clean-up using RP-HPLC. While 34% of the samples contained detectable levels of total aflatoxins (0.20-208.75 µg kg(-1)), only 9% of them exceeded the EU limit of 4 µg kg(-1) in the range 2.0-208.75 µg kg(-1), respectively. A substantial increase in the incidence of aflatoxins was observed in 2008, most likely due to the drought stress experienced in Aydin province as occurred in 2007.

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Sampling cottonseed lots for aflatoxin contamination

Cited by 19 publications

References 4 publications

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

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

Evaluation of cottonseed aflatoxin testing programs

Comparison of homogenization techniques and incidence of aflatoxin contamination in dried figs for export

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