A human fungus zombie from the TV show “The Last of Us”. Credit: Liane Hentscher/HBO
Pancakes won’t turn you into a zombie like in HBO’s “The Last of Us,” but mushrooms in flour have been making people sick for a long time.
In the HBO series “The Last of Us,” named after the popular video game of the same name, the world’s flour supplies are contaminated by a fungus called Cordyceps. When people eat pancakes or other foods made with this flour, fungi grow inside their bodies and turn them into zombies.
As a food scientist, I study the effect of processing on the quality and safety of fruits and vegetables, including flour used to make pancakes. Although no one becomes a zombie eating pancakes in real life, the flour is often contaminated with fungi that can produce mycotoxins that make people sick. However, proper processing and cooking can usually ensure your safety.
“The Last of Us” is based on a pandemic that brings the world to an apocalyptic meltdown.
How common are fungi in flour?
People have been eating wheat bread for about 14,000 years and growing wheat for at least 10,000 years. In 1882, “drunken bread disease” was first documented in Russia, where people reported dizziness, headaches, shaky hands, confusion, and vomiting after eating bread. Long before that, Chinese peasants reported that eating pink wheat – a key sign of infection with a mold called Fusarium – made them sick. Obviously, mushrooms have been making people sick for a long time.
Wheat, corn, rice and even fruits and vegetables can be infected with fungi when growing in the field. In “The Last of Us”, an epidemiologist theorizes that climate change is causing the fungus to mutate so it can infect humans. The sad reality is that fungi have become more of a problem in recent years as warmer temperatures encourage their growth.
A 2017 study found that over 90% of wheat and corn flour samples in Washington, D.C. contained live fungi, with Aspergillus And Fusarium the main types of molds in wheat flour. Fusarium grows on wheat in the field and can cause a common disease of agricultural plants called fusarium head blight or scab.
Farmers use several techniques to reduce this devastating plant disease, including implementing crop rotation, using resistant varieties and fungicides, and minimizing irrigation during flowering. After harvest, they sort the grains to remove contaminated wheat before grinding them into flour. Although sorting removes most of the contaminated wheat, small amounts of fungi can still end up in flour.
Aspergillus is one of the predominant molds found in wheat flour.
Kill microorganisms in flour
The good news is that most fungi and other microorganisms die at 160-170 degrees Fahrenheit (71-77 degrees °VS). So, unlike “The Last of Us”, as long as you bake or fry your batter, you will have killed the mushrooms.
The problem arises when people eat the flour without cooking it first, such as by consuming raw cookie dough or “licking the bowl clean”. Raw egg and raw flour can contain microorganisms that make people sick. The microorganisms of most concern to public health officials are E.coli And Salmonelladangerous pathogens that can cause serious illnesses.
Most people don’t realize that the flour they buy at the store is raw flour that still contains living microorganisms. Flour is rarely commercially processed for safe consumption raw, as consumers almost always cook flour-based foods. Although consumers can also attempt to heat treat raw flour at home, this is not recommended as the flour may not be rolled out thin enough to kill all microorganisms.
Some fungi and microorganisms can create spores, which are like seeds that help them survive in adverse conditions. These spores can survive cooking, drying and freezing. There are even 4,500-year-old yeast spores that have been awakened and turned into bread. These fungal spores rarely cause serious illness in humans, except in those with weakened immune systems.
Chemicals can be added to foods to stop fungal growth. These additives include sorbates, benzoates and propionates. However, you almost never see these additives in flour or pancake mix because the fungi cannot grow in a dry powder. Mushrooms grew either on wheat in the field or on bread after it was baked. For this reason, you may see these additives in bread but not in a powdered mix.
It might be best to leave that moldy bread alone.
Mycotoxins
The greatest risk from fungi is not that they grow inside our bodies, but that they grow on wheat or other foods and produce chemicals called mycotoxins which can cause serious health problems. When wheat is harvested and ground into flour, mycotoxins can mix into it.
Unfortunately, while normal cooking can kill microorganisms, it does not destroy mycotoxins. Consumption of mycotoxins can cause problems ranging from hallucinations to vomiting and diarrhea to cancer or death. Some of the common mycotoxins found in grains include aflatoxins, deoxynivalenol, ochratoxin A, and fumonisin B.
The oldest known case of mycotoxin poisoning is recorded as a disease called ergotism. Ergotism was mentioned in the Old Testament and has been reported in Western Europe since the year 800. It has even been suggested that the Salem witch trials were caused by an outbreak of ergotism which led its victims to hallucinate, although many have disputed this idea. Wheat is less likely than other grains to contain dangerous mycotoxins, which is why some have proposed that the decline in mortality in 18th-century Europe, especially England, was due to the shift from a diet to rye-based to a wheat-based diet.
In the end, you don’t have to worry about eating these pancakes. Farmers use many techniques to minimize fungal growth and eliminate moldy grains, and the government closely monitors mycotoxin levels during crop production and storage. Just be sure to cook your baked goods before eating and don’t eat anything that has started to go moldy.
Written by Sheryl Barringer, Professor of Food Science and Technology, Ohio State University.
This article first appeared in The Conversation.