NEXT PAGE

Grain & Feed Milling Technology is published six times a year by Perendale Publishers Ltd of the United Kingdom.All data is published in good faith, based on information received, and while every care is taken to prevent inaccuracies, the publishers accept no liability for any errors or omissions or for the consequences of action taken on the basis of information published. ©Copyright 2010 Perendale Publishers Ltd. All rights reserved. No part of this publication may be reproduced in any form or by any means without prior permission of the copyright owner. Printed by Perendale Publishers Ltd. ISSN: 1466-3872

Digital Re-print - July | August 2010 Fusarium mycotoxins – What’s all the fuss about?

www.gfmt.co.uk

NEXT PAGEPREVIOUS PAGE

Fusarium mycotoxins are toxic chemicals produced by a group of fungi called Fusarium. These

fungi produce mycotoxins when they infect cereals, resulting in a disease called fusarium head blight (see photo). Fusarium infects the crop during flowering in early June and symptoms develop about a month later in early July.

Ten years ago farmers and processors were largely unaware of what fusarium mycotoxins were, let alone aware of the potential issues.

But things have changed drastically since then and mycotoxins are now one of the top issues for wheat quality. In 2006, the European Commission set legislative maximum limits for fusarium mycotoxins, deoxynivalenol (DON) and zearalenone (ZON) in unprocessed cereals and finished products.

The Home Grown Cereals Authority (HGCA) and Food Standards Agency (FSA) awarded two research grants to Harper Adams University College to identify the extent of fusarium mycotoxins in UK cereals and the impact of agronomy in 2001.

These five-year projects identified the varying extent to which UK cereals suffer from myco-toxin contamination and the “Good Agricultural Practice” that can be adopted to minimise the risk from fusarium mycotoxins.

Unfortunately, the project identified that the fusarium mycotoxins concentration is highly dependent on weather with rainfall at key growth stages of the crop being critical. The

extent of the fusarium mycotoxin issue there-fore fluctuates each season depending on rainfall in early and late summer.

The HGCA has developed a fusarium risk assessment to allow growers to assess the risk of exceeding the legal limits for fusarium myco-toxins in harvested wheat.

The assessment is based on the known risks and includes both agronomic factors (loca-tion, rotation, cultivation, varietal resistance and fungicide use) and rainfall at key stages of crop development (flowering in early June) and pre-harvest (August).

The risk assessment is a Crop Assurance Scheme requirement and the score is included on the grain passport. If the score is high then a DON test should be performed to check the level present.

At the moment, National Association of British and Irish Millers (Nabim) request a DON test is completed for each consign-ment of wheat delivered to mills irrespec-tive of the risk assessment score. This will be reviewed after the start of the 2010 intake and maybe relaxed based on early season results.

One of the trade issues raised by the mycotoxin legislation is that grain is sold based on a quality specification of milling or feed wheat and yet, feed wheat may be sold on for human consumption.

Growers consider that if grain is sold as feed wheat then it is destined for animal feed and does not require a fusarium risk assessment or mycotoxin test.

In reality, if the grower does not know the intended end use, he should not assume it is for animal feed; “feed wheat” in the grain trade is used as a quality specification rather than a defined end-use.

Robust moleculesFusarium mycotoxins, DON and ZON are

robust molecules and there is very little reduc-tion during processing, even with high tempera-tures for example, baking.

The main reduction achieved during processing is partitioning during cleaning and milling. Higher

concentrations exist in small and damaged grains and in chaff and dust, so cleaning can give some reduction, but this is highly dependent on the qual-ity of the grain consignment before cleaning.

Higher concentrations also exist in the bran compared to the flour fractions, so milling results in an increase in mycotoxins in the bran fraction and a decrease in the flour fractions compared to the original grain.

Experimental results have shown that the dis-tribution of DON and ZON is different within the grains. DON is highly water soluble and can therefore move within the grains if repeatedly rehydrated (eg during a wet harvest), whereas

ZON has low water solubility and appears to largely remain where it was produced, which is mainly in the bran fraction.

Results from the 2008 harvest agreed with previous findings that DON is produced in early summer during Fusarium head blight infection and ZON is produced in late summer as the crop ripens.

This results in a change in the mycotoxin profile depending on when in the summer we have rainfall.

A wet delayed harvest results in a greater increase in ZON than DON. In this scenario, as experienced in 2004 and 2008, we have more wheat exceeding the ZON limit than the DON limit. The 2008 was the worst wet harvest experienced for many years and we had close to 30 percent of the harvested UK wheat crop exceeded the legal limit of 100ppb ZON. This

Table 1: Maximum mycotoxin limits for wheat and wheat products

Product

Mycotoxin (ppb)

DON ZON

Unprocessed wheat 1250 100

Grain and mill fractions for human consumption 750 75

Wheat-based products 500 50

Wheat-based products for infants 200 20

Note: Limits for barley and oats are as above except DON limit for unprocessed oats is 1750ppb

Good Agricultural Practice to

reduce fusarium mycotoxins

- Use Fusarium resistant varieties

- Avoid maize as previous crop

- Plough to bury crop debris; if using

min-till, chop/mix as much as possible

- Use a high rate of a recommended

head blight fungicide at correct

timing (early flowering)

- Avoid lodging and harvest delays

Fusarium mycotoxins – What’s all the fuss about?

by Prof Simon Edwards, Harper Adams University College, UK

If the grower does not know the intended end use (of grain), he should not assume it is for animal feed; “feed wheat” in the grain trade is used as a quality specification rather than a defined end-use

Grain&feed millinG technoloGy30 | July - august 2010

FeatureFusarium mycotoxins

was a major issue for the industry, but particularly for bran production as the majority of UK wheat would have produced bran greater than 100ppb.

As a result of these high levels and the dif-ficulty in supply of bran that would allow produc-tion of high-fibre finished products within limits the European Commission set a one-year derogation for high-fibre breakfast cereals and wheat bran as an intermediary product of 100ppb and 125ppb

ZON respectively which ended in October 2009.There is much less of an issue for fusarium

mycotoxins in feed. There are guideline limits of 8000ppb DON

and 2000ppb ZON for wheat intended for animal feed.

These levels are very rare in UK cereals. There are lower limits for finished feeds and these vary for different livestock due to differences in sensi-tivity, with lowest limits set for pig feed.

Ruminants and poultry appear more tolerant to fusarium mycotoxins although there were reports of poor hatchability in poultry after the 2008 harvest.

An evolving diseaseIt is important to note that fusarium head

blight is an evolving disease and continues to change. Fusarium graminearum, the main producer of DON and ZON, is increasing in Northern Europe and is currently spreading up the eastern side of the UK. From 2001-2005, levels of fusarium mycotoxins were consistently low in Scotland, but in 2009, the first wheat sam-ples above legal limits for DON were identified

in the south east of the country.

The situation for barley and oats is different.

For barley, fusarium mycotoxin levels have been consistently low with only a few samples exceeding the ZON limit as a result of delayed harvests. For oats, DON and ZON levels have been consistently low but oats have relatively high levels of two other closely related toxins, HT2 and T2. There is currently no legislation for these mycotoxins but legislation is under discussion and could be an issue of oat processors depend-ing on limits set.

HGCA contin-ue to fund research at Harper Adams, Fera and TAG to improve the fusari-um risk assessment. This includes more precise modelling of weather data and the use of early in-field monitoring of fusarium inocu-lum in the spring.

Percentage of UK wheat harvest samples exceeding legal limits for DON and ZON

Year DON ZON

2001 0.4 0.7

2002 1.7 0.6

2003 2.4 1.2

2004 5.5 11.3

2005 1.5 1.2

2006 0.0 0.3

2007 4.0 2.7

2008 13.1 28.6

2009 2.0 5.3

There are otherways to bindmycotoxins…

T5Xmuch more thana Toxinbinder

T5X has four major actions :

T5X binding components have beenselected in a sophisticated “in vivo”model. Mycotoxins do not pass throughthe intestinal wall.

T5X stimulates the production of specificnatural detoxication enzymes to catalysethe elimination of the mycotoxins.

T5X powerful antioxidants inhibit freeradicals and prevent cells' membranefrom degradation.

T5X stimulates the non specific immunesystem to strengthen animals

Additives & difference

B.P. 394 - 56 009 VANNES Cedex - FRANCENeovia@evls.net

a brand of the

group

PUB85x254-T5X 28/01/10 14:22 Page 1

Related companies

Calibre Control5-6 Asher Court Lyncastle Way, Appleton, Warrington, WA4 4ST, United Kingdom

Tel: +44 1925 860401Email: info@calibrecontrol.comWeb: www.calibrecontrol.com

Perstorp Performance AdditivesIndustrieweg 8Waspik, 5165 NH The Netherlands

Tel: +31 416 317700Fax: +31 416 316698Email: info@perstorpfeed.com Web: www.perstorpfeed.com

Grain&feed millinG technoloGy July - august 2010 | 31

Feature Fusarium mycotoxins

PREVIOUS PAGEwww.gfmt.co.uk

LINKS• Seethefullissue• VisittheGFMTwebsite

• ContacttheGFMTTeam

• SubscribetoGFMTA subscription magazine for the global flour & feed milling industries - first published in 1891

August 2010

• Mycotoxintesting:

ready for this year’s harvest?

In this issue:

• Technical design and equipment - Key to improving

feed quality and nutrition

• Factors affecting pelleting

and energy consumption

• Fusarium mycotoxins

– What’s all the fuss about?

• MakingFeedPellets

• AddedvaluebyFlourHeatTreatment

ThisdigitalRe-printispartoftheJuly|August2010editionofGrain&FeedMillingTechnologymagazine.Contentfromthemagazineisavailabletoviewfree-of-charge,bothasafullonlinemagazineonourwebsite,andasanarchiveofindividualfeaturesonthedocstocwebsite.Pleaseclickheretoviewourotherpublicationsonwww.docstoc.com.

Topurchaseapapercopyofthemagazine,ortosubscribetothepapereditionpleasecontactourCirculationandSubscriptionsManageronthelinkadove.

INFORMATIONFORADVERTISERS-CLICKHERE

Article reprintsAll Grain & Feed Milling Tecchnology feature articles can be re-printed as a 4 or 8 page booklets (these have been used as point of sale materials, promotional materials for shows and exhibitions etc).

If you are interested in getting this article re-printed please contact the GFMT team for more information on - Tel: +44 1242 267707 - Email: jamest@gfmt.co.uk or visit www.gfmt.co.uk/reprints