Mycotoxins - secondary metabolites produced by a variety of moulds on several agricultural commodities under specific environmental conditions.
It has been estimated that at least 25% of the grain produced each year worldwide is contaminated with mycotoxins. In temperate climates such as Canada, the mycotoxins of major concern are the trichothecenes (including deoxynivalenol (DON), nivalenol (NIV), T-2 toxin and HT-2 toxin), zearalenone (ZEN), the fumonisins (FB) predominantly fumonisin B1 (FB1), the ochratoxins, predominantly ochratoxin A (OA), and ergot. However, aflatoxins (AF) are of concern in food and feedstuffs imported from warmer tropical and subtropical regions. Canada's indigenous mycotoxins occur mainly in cereal grains and corn, although occasionally there have been reports of contamination of other crops such as alfalfa and oilseeds, and foods such as coffee, cocoa, rice, beer and wine. As analytical techniques evolve to become more sensitive and widely available, the documentation of widespread contamination in a variety of commodities and of new mycotoxins no doubt, will increase.
Additional Information can be found below, and on the Canadian Food Inspection Agency (CFIA) website.
Farmscape Article 1897-August 27, 2005
Western Canada Braces for Elevated Fusarium Contamination in Feed Grains
The University of Alberta warns this summer's combination of abundant rain and warm temperatures means livestock producers will need to be on alert for potentially elevated levels of fusarium graminearum infection in feed grains.
Fusarium head blight is a fungal infection that primarily affects cereal crops. Fusarium graminearum, the strain of particular concern, is present throughout Manitoba and into Eastern Saskatchewan with the Red River Valley tending to face the highest risk.
Vomitoxin Poses Greatest Concern for Livestock
University of Alberta Feed Industry Chair Dr. Ruurd Zijlstra says the main concern among livestock producers is vomitoxin.
“Vomitoxin can be very toxic especially to pigs but also to other livestock species.”
Dr. Zijlstra points out pigs are generally considered to be most sensitive. “When we look at inclusion levels of vomitoxin that can be tolerated CFI (Canada Foundation for Innovation) might be looking at levels of one PPM but certainly some research indicates that pigs might be able to tolerate two parts per million of vomitoxin.” He adds, “Obviously that is a very low level relative to what cattle might be tolerating, at five or ten parts per million.”
He suggests, “For this particular compound, we could expect very drastic reductions in productivity starting with reductions in feed intake and very drastic reductions in growth performance.”
Manitoba Expected to be Hardest Hit
Although Fusarium graminearum is found in Saskatchewan the problem is most severe in Manitoba. David Kaminski, a Farm Production Extension Pathologist with the Crops Branch of Manitoba Agriculture and Food, says, “We can’t give hard numbers at the moment because not a lot of the spring crop has come off.”
“It is significant and it has been worse than it has been for the last two years when we've really been spared a whole lot of fusarium infection in the cereals.” Kaminski adds, “We do know that the winter wheat crop was especially hard hit and some of the first spring wheat that has been harvested, predominantly in the southwest has been grading a number three – They had an abundance of rainfall, an overabundance in the spring and early summer. That's not good news. It indicates a significant level of fusarium infection in the crop.”
“In the Red River Valley,” he says, “there’s a lot of cropland that did not get seeded or was flooded and later not harvested so, there, it's going to be difficult to assess how much loss was due to disease and how much loss was due to weather alone.”
Fusarium Infection Very Low in Saskatchewan
The fusarium situation becomes far more encouraging once you cross into Saskatchewan.
Each year Saskatchewan Agriculture and Food conducts surveys across the province to determine the amount of disease severity and which species are causing the problem. Provincial Plant Disease Specialist Penny Pearse says, “In terms of the disease that's been showing up in 2004 and 2005, overall, we’ve had low severity levels and we’re looking at generally less than one percent severity.”
She explains, “If we were to take all the grain on average in the province and looked at it, less than one percent of those kernels would actually be having any kind of fusarium species present.”
“In 2005, as you know, we had quite a moist spring and our crops got off to a great start, lots of humidity and warm conditions, which typically would favor fusarium but, for the most part, once the crop started to flower, that humidity was shut down. In Saskatchewan, we have quite a diverse environment, a little bit of Manitoba and little bit of Alberta, in terms of what we’re seeing for disease.”
Highest Fusarium Levels in Saskatchewan Reported in Southeastern Areas
Pearse observes, “On the eastern side of our province, bordering onto Manitoba, especially our southeast, is where we have had most of the fusarium head blight showing up. However we have seen scattered amounts across the province but, overall, (at) very low severities.”
“Fusarium graminearum is the one that most people are concerned with because it’s the one that will produce the mycotoxins in the grain. Fortunately in Saskatchewan that one is still fairly low. We typically have the fusariums in the complex that aren't mycotoxin producers.”
While the actual data is not yet available for 2005, Pearse says, “From 2004, of our total fusarium species, fusarium graminearum accounted for 17 percent (of infection) in the wheat and three percent in our barley. The rest were non mycotoxin producers.”
She adds, “The graminearum, we found mostly in the southeastern part of our province and it would also be a little bit more common in our irrigated areas. Although it’s more prevalent in those regions, our overall percentage of disease is still low.”
Vigilance Considered Best Defense
Dr. Zijlstra recommends, “The main precaution is to be sure you're aware of the levels or potential levels of vomitoxin in the feed. There is not a bullet proof system in place by which you can guarantee a lack of risk.”“There is not a rapid evaluation method available to indicate what is the particular vomitoxin level of a load of grain that you're dealing with right in front of you. Since that’s the case and since we’re using a very high amount of feed grains in our feed formulations the risk management should be implemented prior to receiving feed grains.”
He recommends negotiating quality guarantees with the suppliers prior to actually purchasing the gain.
“That would be step number one and that generally is just about the only thing that you can do to have the highest guaranteed rate of success.”