Almost half of the wheat grown in Europe is contaminated with fungal toxins – albeit mostly in low concentrations. This is reported by a British research team after evaluating the data from authorities and the agricultural industry. The toxins come from Fusarium fungi, which infect and damage wheat and other grains. In humans and animals, these mycotoxins can cause nausea, vomiting, and digestive problems, as well as possibly other ailments. Although there are limit values for concentrations of such substances in wheat, the long-term consequences of consuming small amounts are unclear.
“Contaminated crops and Fusarium toxins are always a concern because they threaten our health and we only partially understand their impact on our well-being,” says study leader Neil Brown of the University of Bath. “In addition, we must not forget that wheat is an enormously important crop worldwide. It is essential that, in addition to producing safe food, we also get high yields.” Yields are currently falling anyway due to climate change and the war in Ukraine – one of the largest wheat producers in the world.
To get an overview of the pan-European extent of mycotoxin exposure, Brown’s team evaluated databases from governments and agribusiness over the past decade from 2010 to 2019. Because wheat is regularly tested for some Fusarium toxins.
Such toxins have been detected in every European country. Overall, almost half (47 percent) of the wheat intended for human consumption in Europe contained the toxin deoxynivalenol (DON), also known as vomitoxin, at least in small amounts. In Great Britain, Sweden and Denmark it was even 69 to 93 percent.
Around 95 percent of the wheat produced for human consumption fell below the specified safety value of 750 micrograms DON per kilogram. If it is exceeded, wheat intended for human consumption will be downgraded to animal feed – this also reduces the selling price. The researchers also found significantly higher toxin concentrations in fodder wheat. Here, too, the threshold of 8,000 micrograms per kilogram was sometimes exceeded, sometimes by a factor of six.
According to this, an estimated 5 percent of the wheat actually intended for humans in Europe from 2010 to 2019 – around 75 million tons – was fed to animals. That means a loss of three billion euros, the team calculates in the journal “Nature Food”.
On the other hand, there are still many unanswered health questions: According to the researchers, it is unclear whether regular, lifelong intake of small amounts of the toxin DON, for example, could damage health. But that’s not all: further studies showed that at least 25 percent of the wheat contaminated with mycotoxins contained other Fusarium toxins in addition to DON – such as fumonisin (FUM), zearalenone (ZEN) or T-2. It is possible that various of these toxins could reinforce each other’s effects and cause particular damage to health.
“We don’t understand the health consequences of exposure to multiple toxins at the same time, especially if that exposure is continuous,” Brown says. “We are concerned about the increasing levels of co-contamination and potential synergies between toxins.”
Another phenomenon worries the team: In the Mediterranean region, these toxins increased during the study period, especially in the last two years, 2018 and 2019. This could possibly be related to cultivation methods or to climate change, the group writes.
“We need to be vigilant when testing grain for mycotoxins,” says co-author Sarah Gurr, a food safety expert at the University of Exeter. “Each of us eats around 66 kilograms of wheat flour per year – for example in the form of pasta and bread. It is important to protect wheat from Fusarium infections.”
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