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Mycotoxins in grain and grain products in South Africa and proposals for their regulation

Dissertation (PhD)--University of Pretoria, 2003.

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Other Authors: Marasas, Walter F.O. (Walter Friedrich Otto)
Format: Thesis
Published: University of Pretoria 2013
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access_status_str Open Access
author2 Marasas, Walter F.O. (Walter Friedrich Otto)
author_browse Marasas, Walter F.O. (Walter Friedrich Otto)
author_facet Marasas, Walter F.O. (Walter Friedrich Otto)
collection Thesis
dc_rights_str_mv © 2003, University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria.
description Dissertation (PhD)--University of Pretoria, 2003.
format Thesis
id oai:repository.up.ac.za:2263/27846
institution University of Pretoria (South Africa)
last_indexed 2026-06-10T12:38:33.011Z
license_str Other — see source repository
provenance_str_mv Harvested via OAI-PMH from UPSpace — University of Pretoria Institutional Repository
publishDate 2013
publishDateRange 2013
publishDateSort 2013
publisher University of Pretoria
publisherStr University of Pretoria
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source_str UPSpace — University of Pretoria Institutional Repository
spelling oai:repository.up.ac.za:2263/27846 Mycotoxins in grain and grain products in South Africa and proposals for their regulation Marasas, Walter F.O. (Walter Friedrich Otto) Wingfield, Michael J. Viljoen, Jan Hendrik Mycotoxins Grain Aflatoxins UCTD Dissertation (PhD)--University of Pretoria, 2003. The purpose of the study was to: ° Report on the occurrence of mycotoxins in grain and grain products in South Africa; ° Compare with other countries; ° Weigh the evidence regarding effects on health of test animals, and human and animal consumers; ° Determine the need for statutory measures to regulate mycotoxins in food; and ° Propose practical measures for controlling mycotoxins in grain and grain products in South Afica. Good mycotoxin data for maize were obtained from the author's surveys. Data on other local grains is lacking. In domestic maize, fumonisins and deoxynivalenol occur regularly, at levels as low or lower than in Argentina and the USA. Other mycotoxins occur rarely, or at very low levels. Deoxynivalenol is likely to occur regularly in domestic wheat. Aflatoxins were virtually absent in domestic maize, but often occur at concerning levels in imported Argentinean and USA maize. The literature show that aflatoxins are acutely and chronically toxic to humans and animals and most countries maintain regulatory Maximum Tolerable Levels (MTLs) for aflatoxins in grain and grain products. Several countries also maintain regulatory MTLs for deoxynivalenol, based on lesser scientific evidence. The mycotoxin that occurs most frequently in South African maize, is the fumonisin B group of analogues, with fumonisin B1 the most abundant. Fumonisins are produced by Fusarium verticillioides (previously known as Fusarium moniliforme) and occur in maize worldwide. Fumonisins cause leukoencephalomalacia in horses, pulmonary oedema in pigs, liver cancer in rats and liver and kidney damage in other animals. A statistical relationship between the occurrence of F. verticillioides and fumonisins in maize and oesophageal cancer in humans has been demonstrated in Transkei and in China. The 'toxins derived from F. moniliforme' and fumonisin B1 have been evaluated as Group 2B carcinogens i.e. possibly carcinogenic to humans, by the International Agency for Research on Cancer of the World Health Organisation. Based on a review of epidemiological and toxicological evidence of the effects of fumonisins on humans and animals, their occurrence in maize and maize products, previously proposed MTLs, and the practical implications of MTLs set for maize and maize products, we propose the following MTLs for total fumonisins in maize and maize products for human consumption: ° 4 µg/g in whole, uncleaned maize; ° 2 µg/g in dry-milled maize products with fat content of >3.0 %, dry weight basis (e.g., sifted and unsifted maize meal); and ° 1 µg/g in dry-milled maize products with fat content of <3.0 %, dry weight basis (e.g., flaking grits, brewers grits, samp, maize rice, super and special maize meal) These MTLs are too high to address a possible link of fumonisins with neural tube defects in neonates. This potential problem remains to be addressed, possibly by fortification of maize products with folic acid. We propose MTLs for deoxynivalenol of 2 µg/g in cereal grains for food use, and 1 µg/g in cereal grain food products. Finally, we propose that the current regulatory MTLs for aflatoxins be raised from 10 ng/g (total aflatoxins in unprocessed maize) to 20 ng/g. Microbiology and Plant Pathology Unrestricted 2013-09-07T12:29:38Z 2003-09-16 2013-09-07T12:29:38Z 2003-05-08 2003 2003-09-10 Dissertation Viljoen, J 2003, Mycotoxins in grain and grain products in South Africa and proposals for their regulation, PhD dissertation, University of Pretoria, Pretoria, viewed yymmdd < http://hdl.handle.net/2263/27846 > http://hdl.handle.net/2263/27846 http://upetd.up.ac.za/thesis/available/etd-09102003-163137/ © 2003, University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. application/pdf application/pdf application/pdf application/pdf application/pdf application/pdf application/pdf application/pdf University of Pretoria
spellingShingle Mycotoxins
Grain
Aflatoxins
UCTD
Mycotoxins in grain and grain products in South Africa and proposals for their regulation
title Mycotoxins in grain and grain products in South Africa and proposals for their regulation
title_full Mycotoxins in grain and grain products in South Africa and proposals for their regulation
title_fullStr Mycotoxins in grain and grain products in South Africa and proposals for their regulation
title_full_unstemmed Mycotoxins in grain and grain products in South Africa and proposals for their regulation
title_short Mycotoxins in grain and grain products in South Africa and proposals for their regulation
title_sort mycotoxins in grain and grain products in south africa and proposals for their regulation
topic Mycotoxins
Grain
Aflatoxins
UCTD
url http://hdl.handle.net/2263/27846
http://upetd.up.ac.za/thesis/available/etd-09102003-163137/