Moldy food cannot be eaten, so why can tofu with hair on it be eaten?

Mold varies greatly in appearance

The appearance varies from silky cottony or granular to tough or smooth velvety and can be colorless, white, gray, brown, black, yellow, green, etc.

As it grows, mold will emit a “ musty ” odor that comes from the VOC vapors it releases.

At present, about 100 kinds of indoor molds have been found to be potentially harmful to human health, including Cladosporium, Alternaria, Fusarium, Penicillium, Aspergillus, Geotrichum, Rhodotorula and Chaetomium . They can cause infection, mainly in the form of ingestion of fungal poisoning , allergic asthma , pneumonia and other diseases. Molds are conditional pathogens, and usually develop under the influence of long-term and large-scale use of broad-spectrum antibiotics, pregnancy, diabetes, tumors and other factors that weaken the immune system.

As common sense, we all know that moldy food cannot be eaten. This is not only because the internal ingredients of moldy food have been destroyed, affecting the taste and nutritional value, but more importantly, it may cause food poisoning. For example, some moldy peanuts and soybeans may also contain aflatoxin , which is a strong carcinogen that can induce cancer and endanger human health.

However, some people still cherish food like gold and are reluctant to throw away moldy food. They only cut off the moldy part and continue to eat the rest. Some people think that if the food is a little moldy, it can be eaten after high-temperature steaming or frying. This is obviously not advisable. Because in addition to the moldy part visible to the naked eye that is cut off, the remaining part may have been invaded by mold . In addition to mold, moldy food may also carry other bacteria and viruses. Some pathogens cannot be killed by high-temperature treatment (such as mad cow disease virus); the temperature of high-temperature cooking can generally only reach 100℃, but aflatoxin can withstand heat of 280℃. Steaming cannot kill harmful substances that withstand high temperatures . Therefore, after eating moldy food cooked at high temperatures, diarrhea, abdominal pain and other food poisoning symptoms may still occur.

Does this mean that moldy food cannot be eaten?

Not really. There are exceptions - hairy tofu

I believe many of you have seen hairy tofu on food shows, which is the "hairy tofu" loved by many people. The Chinese people have a very long history of eating hairy tofu, which began around the Yuan Dynasty.

So is Mao tofu poisonous?

Is it safe to eat?

First, let’s take a look at how Mao tofu is formed.

Hairy tofu

The reason why it grows hair is that excellent Mucor is directly inoculated on tofu under sterile conditions, and stored in an environment with very suitable temperature and humidity. After artificial fermentation, a kind of white hair grows, which is the aerial hyphae of Mucor. Traditional or homemade hairy tofu comes from Mucor spores in the air and may be contaminated by other species. Tofu with black, green, or yellow hair is inedible and may be moldy and spoiled.

The surface of hairy tofu is full of white hair, but it does not mean that the food is rotten. In fact, the formation of hairy tofu is a fermentation process . During the fermentation process, the plant protein in hairy tofu will be converted into a variety of amino acids . Hairy tofu, fermented bean curd, and black beans are all fermented bean foods. Therefore , hairy tofu smells bad but tastes delicious. It is harmless to the body and can be eaten with confidence.

To sum up, we need to scientifically identify "moldy" foods in our lives, recognize the true face of "mold", and discard truly moldy and rotten foods in time. We must not eat them because we feel sorry for them, fear of waste, or rely on luck . Of course, when faced with hairy tofu disguised as "snowy", we don't need to worry too much and keep the delicious food away from us.

To learn more about "bacteria", please click on the academic article:

Analysis of bacterial resistance in Peking Union Medical College Hospital in 2019, Peking Union Medical College Journal

Original author: Liu Wenjing, Xu Yingchun, Yang Qiwen, Wang Yao, Sun Hongli, Zhao Ying, Dou Hongtao, Liu Yali, Guo Lina, Zhu Renyuan, Zhang Li, Xiao Meng, Zhang Xiaojiang

Editor: Liu Yang and Zhao Na

Proofreading: Li Na, Li Yule, Dong Zhe, Li Huiwen

Producer: Wu Wenming

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