There may be mold in your munchies: Fighting mycotoxins in Canada

Mycotoxins, toxins created by mold, can be found in everything from grains to nuts to fruit. Some directly damage the liver, the kidneys or the nervous system and others have been labelled as carcinogens.

“This disease has been a problem in America since colonial times,” explains J. David Miller, a professor of toxicology at Carleton University and one of Canada’s leading mycotoxin experts. “It’s a massive problem all over the cereal world.”

So far, over 300 different kinds of mycotoxins have been identified—and only a few are regulated in Canada. But research being done at Carleton University may make it easier to detect and eliminate these toxins.

For Ontario, whose farmers grow 1.5 million tonnes of wheat and 5.5 million tonnes of corn each year, mycotoxins are a huge issue.

The main culprit is Fusarium graminearum, a mold found on corn and wheat. This mold produces deoxynivalenol, zearalenone and fumonisin, mycotoxins which can cause everything from liver damage to fertility problems in high doses.

Southern Ontario and its southern neighbour, New York State, have the most severe and frequent deoxynivalenol problems in North America. Ontario crops suffer from Fusarium every single year—and most of the wheat produced in Ontario is eaten locally.

Ontario uses a handful of management strategies to control these toxins. The process begins out on the field. Special machines that measure temperature and moisture levels are placed in every farmer’s field as part of Canada’s DONcast management system. These machines predict when plants will be vulnerable to Fusarium, and whether farmers should use fungicides.

Researchers have also tried to breed more resistant crops—but farmers have been reluctant to adopt them because they don’t yield as much product.

Sampling is the main method manufacturers use to prevent the contamination of human food. Raw material may be tested multiple times before it reaches its finished form. But even with all the extra precautions, sampling can still be tedious and flawed.

Sampling one of the main methods used to prevent mycotoxin contamination. Annamaria Ruscito is working on a cheaper way to do this sampling

Tests begin when the farmer brings his grain to the nearest grain elevator after harvest. Workers at the grain elevator do a quick visual check—grains infected by mycotoxins are often shrivelled and sometimes take on a pinkish colour.

This visual inspection is useful, but often grains affected by mycotoxins show no outer signs. More extensive chemical testing could be used, but the problem comes with the amount of grain transported in Canada.

“There are 9,000 country elevators, there are 600 terminal elevators, there are 122,000 trucks that move grain, and God knows how many rail cars,” explains Miller. “At harvest time, you could have trucks lined up for three miles near the elevator, and let’s be serious, they don’t want somebody in a white coat saying, ‘Oh, you have to wait an hour before it’s okay to put it in.”

Because Canada only regulates a handful of mycotoxins, most companies limit them voluntarily.

“Canada and the US do not have regulations for a number of mycotoxins,” explains Susan Abel, the vice president of safety and compliance for Food and Consumer Products of Canada.  “For some mycotoxins, there is either limited guidance or voluntary limits.”

Abel explains that food manufacturers often require a certificate of analysis—a paper showing the grain they receive is mycotoxin-free—from the farmers who sell them raw materials. Once they get the shipment, they spot check it to see if any mycotoxin-infected grain has slipped through before they make the finished product.

This is where Carleton’s newest research comes in. Testing for mycotoxins can be expensive, especially considering the amount of grain produced in Canada. The ELISA test is the standard method, and costs $50 to $80 per test.

This method uses a test strip with mouse antibodies that have been immunized against certain mycotoxins in order to detect whether these mycotoxins are present. It is the standard method, and often costs $50 to $80 per test.

Carleton bioinorganic chemistry professor Maria DeRosa is looking at a cheap way to replicate this test using DNA aptamers, randomly generated strings of DNA bases.

“This is world class,” praises Miller, who has encouraged the research from the beginning. “It’s a very important thing.”

DeRosa and her team use a DNA synthesizer to string together random strands of DNA bases. These strands are then tested to see if they will bind to different mycotoxin molecules.

First, they are put through a test tube that contains magnetic beads. Anything that sticks to the wall or to the beads is discarded.

Annamaria Ruscito runs a mycotoxin sample through a test tube. She is part of a team at Carleton University working on a better way to sample for mycotoxins.

Next, the strands are run through the same column, but this time mycotoxin molecules are attached to the beads. Any of the DNA strands that bind with the mycotoxin molecules are replicated. These copies are tested in a variety of conditions to make sure they will work consistently.

So far, the team has found matches for ochratoxin A and fumonisin, both common in Ontario. The researchers are still searching for matches to deoxynivalenol and patchoulin.

The envisioned test strip is a long way from becoming a reality. But once it does, it will be a much more cost effective way to test for mycotoxins, explains Annamaria Ruscito, a PhD student working on the project.

“Because we don’t use an animal to get these antibodies, it’s not only more compassionate, but you don’t have to go through the costs of buying animals and cages,” she explained. “Once you have a sequence, you can make a million of them in a machine and it doesn’t cost anything.”

While the mouse antibodies in the current ELISA test cost dollars to produce, the DNA bases used to make aptamers only cost cents.

The new test will also help bridge the gap between large companies and smaller operations. Smaller companies often have trouble testing for mycotoxins because they lack the funds and trained personnel to do so. This aptamer test would provide a cheap way to double check with no training required.

Even with more accessible testing methods, fighting against mycotoxins is still a complex and labour-intensive process. Yet many consumers have no idea that mycotoxins exist. Miller says this is because food companies don’t want people worrying about the food they eat.

“What you don’t know and possibly what the food companies don’t want you to know is that they are right on this,” he explains. Companies don’t want to alarm consumers, who may then avoid certain food products.

“They absolutely don’t want you to think that there’s anything in your Timmy’s or your Kellogg’s breakfast cereal,” says Miller.

According to Miller, manufacturers are right to keep the issue under wraps, because mycotoxins are well-controlled. Farmers, the government and manufacturers have multiple checks and balances in place to manage the issue.

Of course, there will always be room for improvement. New technologies and techniques like the DNA aptamer test will play a key role in the future of mold management.