Farmers Weekly has recently reported that 90% of grain samples tested were infected with Fusarium species resulting in a high number of load rejections
It is felt that 2007 could prove to be the worst year in recent history for incidences of high levels of mycotoxins in grain.
The wet weather in the summer is likely to have contributed to this phenomenon and while current reports suggest high levels of field mycotoxins, if the damp weather continues then the situation could be further worsened with recently harvested grain at risk from storage mycotoxins.
Reports in Farmers Weekly and Farmers Guardian both highlight the field mycotoxins - fusariums (fumonisins, trichothecenes and zearalenone) - as being of major concern.
Highly sensitive Elisa quantitative and qualitative analysis services are available from Genon Laboratories (a Ukas-accredited testing laboratory).
A screen is available to detect several different mycotoxins at low cost and - unusually - customers can specify which mycotoxins are included and the limits of detection to be used in the screen.
It is advisable to test stocks as early as possible to avoid expensive production and transportation costs in the event that grains have to be rejected.
Furthermore a quantitative result can help manufacturers to allocate stock effectively, for example where levels of mycotoxin leave the grain only suitable for certain production routes.
Field mycotoxins.
Those mycotoxins more commonly found in the field are fumonisins, trichothecenes (including deoxynivalenol/DON/vomitoxin, T-2 and HT-2) and zearalenone.
Fusariums often co-occur and therefore screen testing that can detect a number of mycotoxins is advisable.
Fumonisins occur particularly in maize and maize-based products while DON is common in cereals and grains (wheat, barley and maize).
In aminal feed fumonisins can cause adverse effects such as equine leukoencephalomalacia and porcine pulmonary oedema.
Pigs are most sensitive to DON, which reduces feed uptake and causes a decrease in weight gain, vomiting and immuno-suppression.
Although they can cause adverse effects to the animals consuming the feed, these field mycotoxins do not transfer through animals to foodstuffs in high enough levels to be of concern to humans.
Ensuring low levels of field mycotoxins in animal feed is there only advisory and not subject to legislation.
Where cereals and grain are intended for human consumption, the contaminants in food regulations (Commission Regulation 1881/2006) come into force.
The legislation sets limits for mycotoxins in foodstuffs such as unprocessed cereals, durum wheat, oats, maize and flour.
Although maximum levels are not yet stipulated for T-2 and HT-2 toxins, a review of these, DON, zearalenone and fumonisins is planned for 1 July 2008 where it is expected such levels will be set.
Storage mycotoxins.
Ochratoxin A and Aflatoxins mainly form during storage and are rarely seen in the field.
They can cause a wide range of acute and chronic effects, for example Aflatoxin B1 is the most potent natural carcinogen known to man and Ochratoxin A causes damage to the liver, kidney and immune system.
Aflatoxin M1 is the hydroxylated metabolite of Aflatoxin B1 and transfers to humans in milk and milk products from animals that have consumed contaminated feed.
As these mycotoxins form in moist conditions, it is important that wet grain is dried as quickly as possible and grain heaps are ventilated.
Any deliveries of grain with a moisture content of 20% or higher should also be rejected as this is at risk from Ochratoxin A formation.
Tests to detect and measure mycotoxins are essential where the grain has been at risk from mould growth as high mycotoxin levels in certain produce are not only illegal but can severely affect the health of animal and human consumers.
Strict levels for the presence of these mycotoxins apply to all cereal-based products intended for human consumption while Aflatoxin B1 is regulated as regards animal feed.
