Do the mushrooms bought at the vegetable market really contain formaldehyde?

Recently, there has been a trend on the Internet to use indoor formaldehyde detection kits to test the formaldehyde content of edible fungi. Many bloggers have come out to test and publish the test results in the form of videos. In the videos, many bloggers claimed that formaldehyde was detected in edible fungi such as shiitake mushrooms, white jade mushrooms and enoki mushrooms. Many viewers were shocked after seeing this and developed a fear of edible fungi. They were afraid that eating these edible fungi containing formaldehyde would cause cancer, and they threatened that they would never dare to eat edible fungi again.

Tuchong Creative

So do the edible fungi sold on the market really contain formaldehyde? Is eating these edible fungi harmful to health? Let's analyze the truth of the whole thing.

01

It is unlikely that formaldehyde is artificially added

Formaldehyde is a colorless organic compound with a pungent odor. It is highly toxic and can cause disease, which is worrying. However, many people do not know that formaldehyde also has a beneficial side. In fact, this organic compound is widely used in our daily life. For example, many fields such as industry, textile industry and medicine cannot do without formaldehyde. It has made great contributions to human industrial development and life convenience. Therefore, when facing formaldehyde, we need to adjust our mentality and face its pros and cons, without excessively talking about it.

In addition, formaldehyde is divided into exogenous formaldehyde and endogenous formaldehyde according to the source of its production. Exogenous formaldehyde refers to formaldehyde added to products by improper use or illegal means, which is the main reason for the excessive formaldehyde content in commercial products. In order to maximize economic benefits, some unscrupulous merchants used formaldehyde as a preservative and bleaching agent to extend the storage time of edible fungi, prevent edible fungi from rotting, and improve the color of edible fungi. These illegal acts have indeed brought adverse effects on the food safety of the people.

Tuchong Creative

However, with the overall improvement of national awareness, the concept of health and environmental protection has gradually gained popularity, and national laws and regulations have gradually improved. According to the current "Food Safety Law of the People's Republic of China", "Agricultural Product Quality Safety Law of the People's Republic of China" and "Food Additive Use Standards" and other relevant regulations, formaldehyde shall not be used as a food processing aid for production and operation, and adding formaldehyde to food in any way is illegal. At the same time, various supervisory departments are always strictly enforcing food safety behaviors. Edible fungi sold regularly on the market will have special supervisory departments to test whether they are of qualified quality. Once found, they will be severely punished.

Therefore, formaldehyde, as a compound with a special pungent smell, is not very hidden and can be easily discovered. Nowadays, it is basically no longer used as a preservative, and few businesses are willing to take the risk and break the law. Therefore, the formaldehyde detected by many people from edible fungi recently can basically be concluded that it is not exogenous formaldehyde.

02

Formaldehyde exists naturally in agricultural products

Since it is not exogenous formaldehyde, but formaldehyde was detected, the reason can only be endogenous formaldehyde. In fact, many organisms will produce formaldehyde themselves because they will carry out biological metabolism, including humans. At present, many scientists have found that edible fungi will produce trace amounts of formaldehyde according to changes in the natural environment. For example, Japanese scholars conducted research on the formaldehyde content and formation mechanism in shiitake mushrooms as early as the 1970s. They believed that the trace formaldehyde in shiitake mushrooms was produced by the metabolism of γ-glutamic acid cysteine, an important flavor substance in shiitake mushrooms, under the action of enzymes, and was a normal metabolic product of shiitake mushrooms. Therefore, it is normal for people to detect trace amounts of formaldehyde in edible fungi.

Tuchong Creative

Since endogenous formaldehyde is produced during biological metabolism and exists naturally in many foods, will it be harmful to the human body? The answer is no. Under normal circumstances, edible fungi have been basically dissolved and disappeared after being washed beforehand and cooked at high temperature for a long time. Even if there is a trace amount of residue, the body has a complete metabolic mechanism, which can generally degrade the trace amount of formaldehyde into CO2, formic acid and water through enzymatic reactions, so it will not be toxic to the human body and can be eaten with confidence.

03

Is indoor formaldehyde test paper accurate in testing edible fungi?

Looking at the recent evaluations of formaldehyde content in edible fungi by many bloggers, most of them use indoor formaldehyde detection kits for testing. However, this detection method has testing loopholes. Because this test paper is a semi-quantitative test paper, it is a product specially used to detect formaldehyde in specific spaces such as indoors. It is easily affected by many factors such as temperature, humidity and air during detection. The test data will produce some errors, and the experimental results may be inaccurate, which may lead to false positive results.

Tuchong Creative

At present, the main methods for detecting formaldehyde in edible fungi are acetylacetone method and pre-column derivatization high performance liquid chromatography. These detection methods require the addition of specific test agents and precision instruments to detect the original formaldehyde content of edible fungi. They have many advantages such as low detection limit, simple and fast operation, accurate and scientific results, etc. They are widely used in food formaldehyde detection by major scientific research institutes and supervision departments, but there has never been a precedent for using indoor formaldehyde test paper to detect formaldehyde in edible fungi. Therefore, from a scientific point of view, the results of using indoor formaldehyde test paper to detect the formaldehyde content of edible fungi are inaccurate, so please do not believe the test results.

In addition, after the trend of using indoor formaldehyde test paper to test edible fungi began, market supervision departments immediately followed up and conducted formal formaldehyde testing, and found no formaldehyde content exceeding the standard in edible fungi. Therefore, as long as the edible fungi are purchased through formal channels, we do not need to worry too much about the harm of eating them.

04

How to better remove formaldehyde?

Seeing this, some people may ask if there is any better way to remove the trace formaldehyde produced by the metabolism of edible fungi? The answer is of course yes, and it is very simple.

1. Clean more frequently before cooking

Formaldehyde is a compound that is highly soluble in water. After purchasing edible fungi, wash them with running water first to remove the bacteria and chemical pesticides on the surface, then soak them in water for 10 minutes. The soaked and washed edible fungi can significantly reduce the formaldehyde content.

2. Edible fungi must be cooked thoroughly.

Formaldehyde is easily dissolved by heat, and the heat generated by cooking helps to remove formaldehyde. According to research, the inactivation of the enzymes that form formaldehyde can inhibit the formation of formaldehyde, but the temperature must reach 90°C for at least 5 minutes to inactivate the enzyme. In addition, during the cooking process of edible fungi containing formaldehyde, almost all the formaldehyde will be evaporated, so there will be no problem if the edible fungi are cooked thoroughly when enjoyed.

Tuchong Creative

Conclusion

Rumors are not scary, what is scary is that rumors always come before the truth. In fact, the controversy over the existence of formaldehyde in edible fungi has been going on for a long time, and it comes up every once in a while, bringing adverse effects to people's production and life. In today's era of comprehensive information technology, we have many ways to check the truth of things, so don't become an accomplice of rumors.

References:

[1] Sun Minhua, Wu Xueqian, Wei Hailong, Fu Lizhong, Wu Qingqi, Li Haibo, Chai Zhenlin. Research progress on toxic and harmful substances in edible fungi and their control and prevention technologies [J]. China Forestry By-products and Specialties, 2007, (05): 74-77.

[2] Zhang Jinxia, ​​Chen Qiang. A brief discussion on the quality and safety of edible fungi[J]. China Agricultural Information, 2012, (16): 16-18.

[3] Wang Ruiqing, He Shihang, Yao Sen, Chen Bingzhi, Jiang Yuji, Xie Baogui. Optimization of pre-column derivatization conditions for formaldehyde content determination in edible fungi and its application[J]. Journal of Food Safety and Quality, 2020, 11(22): 8528-8532.

[4] Yu Qilin, Li Jianrong. Sources and control of formaldehyde in food[J]. Modern Food Science and Technology, 2007, (10): 76-78.

[5] Xing Zengtao, Zhao Xiaoyan, Tan Qi, Liu Haiyan. A brief analysis of the 2012 edible mushroom "Oyster mushroom formaldehyde" incident [J]. Fungal Research, 2012, 10(03): 210-212.

Author | Li Ting

Review | Han Hongwei, Director of the Communication Department and Researcher of the National Food Safety Risk Assessment Center

This article is produced by the "Science Rumor Refutation Platform" (ID: Science_Facts). Please indicate the source when reprinting.

The pictures in this article are from the copyright gallery and are not authorized for reproduction.