Cereals and grains are promoted by dietitians, doctors and wellness influencers for their robust nutrition profile and health benefits.
But, scientists are warning of the hidden health risks posed by these foods, saying they could be laced with toxins that threaten health.
In a review of 258 studies, researchers in North Carolina found virtually all cereal products — including rice, oats, wheat and corn — contain mycotoxins, toxic chemicals released by fungi.
These can contaminate crops, such as wheat, in the field or after harvest during packaging, storage or processing in the factory, where moisture can trigger mold growth, and then cause sickness when the food is eaten.
Strict limits on the amounts of mycotoxins in foods are set by the FDA, but the experts warn that ingesting food containing high levels could cause sickness.
Limits vary depending on the type of mycotoxin, but are normally about 20 parts per billion. The FDA says it regularly tests cereals on shelves to ensure that they do not exceed these levels.
People who ingest a lot of mycotoxins at the same time suffer sudden acute illness, with symptoms including stomach pain and indigestion. While eating the food, they may also suffer from coughing, caused by breathing in fungal spores on the food.
But people can also be sickened by consuming small amounts of mycotoxins over a long period, which build up in the blood.
Researchers have warned over the presence of mycotoxins, toxins released by molds, in cereals (stock image)
Warning signs include asthma, cancer and short-term memory loss. In serious cases, the toxins can also cause convulsions, lead to a coma and death. Young children, the elderly and pregnant women are most at risk from the toxins.
In April last year, the FDA issued a recall for 170,000 bottles of Martinelli’s Apple Juice sold across 28 states after it was found to be contaminated with mycotoxins produced by mold on apples. No sicknesses or deaths were linked to the outbreak.
Several outbreaks of mycotoxins involving pets have been recorded in the US over the last two decades. In January 2021, more than 110 dogs died and 210 were sickened after eating pet food that had been contaminated with aflatoxin, a mycotoxin released by mold.
For the apple juice, officials said the mycotoxins that caused the recall are made by a fungus that causes apples to go moldy. For the animal food recall, tests revealed it had been infested with a fungus that can colonize grains if they are not stored properly.
There have been no recent mycotoxin outbreaks among humans in the US, however, there is a high risk of an outbreak given how widespread contamination is in common products.
Cereals and grains are a major part of the human diet, and because they are healthy, they are encouraged as part of a balanced diet, including brown rice and oats, as they contain a wide variety of needed nutrients.
The mycotoxins are found in virtually all cereals sold in the US, experts said, but at very low levels (Stock image)
But in their study, published in the journal Toxins in 2023, researchers at North Carolina Agricultural and Technical State University warned these ‘health foods’ likely contained the dangerous toxins.
They wrote: ‘This review shows that exposure to mycotoxins is unavoidable because the cereal grains which are staples for both food and feed are more or less contaminated globally.
‘Severe mycotoxin contamination makes the food unsuitable for human and animal countries.’
They added: ‘In developed countries, mycotoxin contamination of cereal grains is not a major food safety issue to adult human beings due to tight regulations and sufficient food supplies, but it is still a risk factor to infants and young children, and it often threatens the health and lives of livestock animals and pets.’
Researchers said mycotoxin levels in foods were normally at safe levels and well below the FDA’s safe limit, set at about 20 parts per billion for most cereals.
They warned, however, that there was a risk that levels could rise enough due to contamination to cause sickness in humans.
Several fungi can infect cereals, but the scientists warned over three main ones; Aspergillus, Fusarium and Penicillium species.
To reduce the risk of high mycotoxin levels in foods, the researchers said there were pre- and post-harvest mycotoxin control strategies in place in many farms.
These included using grains that had been specially bred to be mold-resistant, and coating seeds and seedlings with plant-derived antifungal proteins. Plants may also be sprayed with fungicides in the field to limit growth.
Fungicides, however, pose their own risks because toxic chemicals from them can linger and cause damage to humans. A previous study, for example, suggested that they could damage neurons.
During storage, grains are dried to minimize the risk of mold growth and kept in secure, clean storage bins.
In cases where mycotoxin levels exceed the recommended threshold, the researchers said manufacturers detoxify the grains using manual sorting to remove damaged grains. Grains may also be treated with mycotoxin binders to help remove them from foods.
Cereal grains are among the most important food staples for humans and livestock animals in the world and make up a major part of diet.
In Europe and North America, many rely on wheat, while in Asia, it is rice, and in Africa and South America, corn is a major part of someone’s diet.
But these are vulnerable to contamination with fungi, though processing and cooking can reduce contaminant levels.
If someone becomes sick from mycotoxins, doctors first try to treat them by removing the source of the mold, such as cereal that has gone bad.
Treatment may also involve taking drugs to support the liver, which filters mycotoxins out of the blood, and medications that can bind to mycotoxins in the body, causing them to be flushed out.
