Stinky tofu

Stinky tofu

　　Stinky tofu “smells bad” because during the fermentation and curing process, as well as subsequent fermentation, the proteins contained in the tofu break down under the action of proteases, and the sulfur-containing amino acids also fully hydrolyze, producing a compound called hydrogen sulfide (H2S), which has a pungent, unpleasant odor. After the proteins decompose, amino acids are produced, and these amino acids have a delicious taste, hence the saying that it “tastes good.”

Stinky tofu smells bad but tastes good. Some people avoid it, while others have made eating it a hobby. In fact, stinky tofu is a type of fermented soy product. During its production, not only are certain decay-related substances generated, but it is also prone to bacterial contamination. From a health perspective, it’s better to eat it sparingly.

Research has shown that during the fermentation of soy products, amine compounds such as methylamine, putrescine, and tyramine, as well as hydrogen sulfide, are produced. These substances have a distinctive foul smell and are highly volatile, and consuming them in large quantities is not beneficial to health. In addition, if amine compounds are stored for too long, they may react with nitrites to form nitrosamines, which are potent carcinogens.

Although small in size, the production process of stinky tofu is quite complex, involving several steps such as deep-frying, brining, and fermentation. Throughout the entire production process, it must be carried out under natural conditions, and it requires very specific temperature and humidity levels. If not properly controlled, it can easily become contaminated with harmful bacteria. In mild cases, this can cause gastrointestinal illnesses, and in severe cases, it may lead to the proliferation of Clostridium botulinum, which produces a toxic substance—botulinum toxin. This is a neurotoxin with extremely high toxicity. Recent reports of stinky tofu poisoning incidents have been attributed to this toxin.

In fact, stinky tofu isn’t entirely without merit. During its production, it can synthesize a significant amount of vitamin B12. A deficiency in vitamin B12 in the human body can accelerate brain aging and is associated with an increased risk of senile dementia. However, vitamin B12 is also found in many animal-based foods such as meat, eggs, milk, fish, and shrimp. Compared to these benefits, the drawbacks of stinky tofu deserve more attention.

If you really can’t give up stinky tofu, it’s recommended that you eat it along with plenty of fresh vegetables and fruits. The vitamin C they contain can help block the formation of nitrosamines.