United States Agency for International Development

Health and Trade Issues Mycotoxin Contamination and Toxigenic Fungi in Africa and the Mediterranean Basin Mycotoxin Detection Methods Mycotoxin Management Institutional Issues in Mycotoxin Management International Programs on Mycotoxins.

Mycotoxins: Detection Methods, Management, Public Health and Agricultural Trade

Mycotoxins are natural contaminants produced by a range of fungal species. Their common occurrence in food and feed poses a threat to the health of humans and animals. This threat is caused either by the direct contamination of agricultural commodities or by a “carry-over” of mycotoxins and their metabolites into animal tissues, milk, and eggs after feeding of contaminated hay or corn. As a consequence of their diverse chemical structures and varying physical properties, mycotoxins exhibit a wide range of biological effects. Individual mycotoxins can be genotoxic, mutagenic, carcinogenic, teratogenic, and oestrogenic. To protect consumer health and to reduce economic losses, surveillance and control of mycotoxins in food and feed has become a major objective for producers, regulatory authorities and researchers worldwide. However, the variety of chemical structures makes it impossible to use one single technique for mycotoxin analysis. Hence, a vast number of analytical methods has been developed and validated. The heterogeneity of food matrices combined with the demand for a fast, simultaneous and accurate determination of multiple mycotoxins creates enormous challenges for routine analysis. The most crucial issues will be discussed in this review. These are (1) the collection of representative samples, (2) the performance of classical and emerging analytical methods based on chromatographic or immunochemical techniques, (3) the validation of official methods for enforcement, and (4) the limitations and future prospects of the current methods.

Determination of mycotoxins in foods: current state of analytical methods and limitations

Sampling for chemical analysis

Preface. Acknowledgements. Relevance of Mycotoxins in the Food Supply and in the Built Environment. Introduction J.D. Miller. Biology and Ecology of Mycotoxigenic Aspergillus Species as Related to Economic and Health Concerns D.M. Wilson, et al. Aspects of the Ecology of Fusarium Toxins in Cereals J.D. Miller. Biology and Ecology of Toxigenic Penicillium Species J.I. Pitt. Chemistry and Toxicology of Molds Isolated from Water-Damaged Buildings B.B. Jarvis. Biological Control of Fusarium Head Blight of Wheat and Deoxynivalenol Levels in Grain Via Use of Microbial Antagonists D.A. Schisler, et al. Analytical Aspects of Mycotoxins. Introduction M.W. Trucksess, S.W. Page. Sampling Wheat for Deoxynivalenol T.B. Whitaker, et al. Novel Assays and Sensor Platforms for the Detection of Aflatoxins C.M. Maragos. Electrospray Mass Spectrometry for Fumonisin Detection and Method Validation S.M. Musser, et al. Recent Advances in Analytical Methodology for Cyclopiazonic Acid J.W. Dorner. Methods of Analysis for Ochratoxin A P.M. Scott. HPLC Detection of Patulin in Apple Juice with GC/MS Confirmation of Patulin J.A.G. Roach, et al. Methods for the Determination of Deoxynivalenol and Other Trichothecenes in Foods G.A. Lombaert. Processing Effects on Mycotoxins. Introduction L.B. Bullerman. Characterization of Clay-Based Enterosorbents for the Prevention of Aflatoxisis T.D. Phillips, et al. Effect of Processing on Aflatoxins D.L. Park. Effect of Processing on Deoxynivalenol and Other Trichothecenes D.M. Trigo-Stockli. Effect of Processing on Ochratoxin A (OTA) Content of Coffee R. Viani. Stability of Fumonisins in Food Processing L.B. Bullerman, et al. Effects of Processing on Zearalenone D. Ryu, et al. Mycotoxins and Fermentation -- Beer Production C.E. Wolf-Hall, P.B. Schwarz. Toxicity, Risk Assessment and Regulatory Aspects of Mycotoxins. Introduction J.W. DeVries. Aflatoxin, Hepatitis and Worldwide Liver Cancer Risks S.H. Henry, et al. Risk Assessment of Deoxynivalenol in Food: Concentration Limits, Exposure and Effects M.N. Pieters, et al. Risk Assessment of Ochratoxin: Current Views of the European Scientific Committee on Food, the JECFA and the CODEX Committee on Food Additives and Contaminants R. Walker. Worldwide Regulations for Mycotoxins H.P. van Egmond. Economic Changes Imposed by Mycotoxins in Food Grains: Case Study of Deoxynivalenol in Winter Wheat A.W. Schaafsma. U.S. Perspective on Mycotoxin Regulatory Issues D.L. Park, T.C. Troxell. Index.

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Mycotoxins and food safety

The sampling, subsampling, and analytical variance associated with testing cottonseed for aflatoxin were estimated by use of 4.54 kg samples, 100 g subsamples, and the Velasco method of analysis. Regression analysis indicated that each of the above variance components is a function of the concentration of aflatoxin in the populations tested. Functional relationships are presented to determine the sampling, subsampling, and analytical variance for any size sample, subsample, and number of analyses.

Variability associated with testing cottonseed for aflatoxin

Large samples called “sublots” were drawn from 41 commercial lots of contaminated cottonseed. Each sublot was subdivided into twenty 5 lb samples which were analyzed for aflatoxin. The mean, median, variance, coefficient of variation, and the estimated range among the sample concentrations were computed. The results indicated that: (A) the variance among sample concentrations was large and was found to be a function of sample concentration and (B) the distribution of sample concentrations was skewed; the density of sample values was greater below the sublot concentration.

Sampling cottonseed lots for aflatoxin contamination.

A rapid screening method for detecting aflatoxins in cottonseed has been developed. Using long-wave ultraviolet light and samples containing aflatoxins, the fibers on a few cottonseed fluoresced a greenish yellow and the ends of some sticks and stems (foreign material) fluoresced with a bluish color. Nine out of 10 of the 2300 samples of cottonseed were correctly screened during the last two years of the study. In only one category, 1–10 ppb aflatoxins, was there an appreciable error in the screening method.

Screening cottonseed for aflatoxins

A computer model was developed to simulate cottonseed aflatoxin testing programs. By use of the model, probabilities of obtaining certain aflatoxin test results for various lot concentrations and sample sizes were determined. Also, the effects of sample size and the definition of good and bad sample quality on the probability of lot acceptance were demonstrated.

Evaluation of cottonseed aflatoxin testing programs.

Small lots of cottonseed with low aflatoxin contamination were stored at 15, 18 and 22% moisture at 80 and 85 F. Maximum aflatoxin content was reached within 30 days’ storage. The range in moisture content was sufficient to cause a 10-fold increase in aflatoxin content between seed stored at 15.1 and 21.8% moisture. Aeration caused about a five-fold mean increase in aflatoxin content.

M. E. Whitten

Papers

Variability associated with testing cottonseed for aflatoxin

Sampling cottonseed lots for aflatoxin contamination.

Screening cottonseed for aflatoxins

Evaluation of cottonseed aflatoxin testing programs.

Effect of storage conditions on increase in aflatoxins in cottonseed: a small lot study.