Cabbage Dipped in Formaldehyde, Real Person Tastes a Hundred “Poisons” | Grandma Kouzi

Recently, food safety news has once again trended on social media after a blogger reported someone dipping Chinese cabbage in formaldehyde. On 22 August, the Kangbao County People’s Government in Zhangjiakou, Hebei Province, issued a situation report stating that a preliminary investigation had confirmed the allegations: vegetable buyers had illegally treated the produce during loading and transport to preserve its freshness.

This sort of story rears its head every so often, yet similar practices persist despite repeated bans. In the era before the very concept of food additives existed, many chemicals were openly added to food to achieve preservation and freshness. But recognising the dangers of these substances, and the struggle over food safety itself, have taken many years.

USDA Officials: Real Human Poison Trials

In 1902, Harvey W. Wiley, Chief Chemist of the Bureau of Chemistry at the US Department of Agriculture, recruited twelve strapping young volunteers within the department to form the “Poison Squad”. Their aim was to prove, through human self-experimentation, that formaldehyde, borax, salicylic acid, saccharin, sodium benzoate and other widely used food additives of the era were harmful to health. Wiley’s trials were conducted entirely in the open, under the scrutiny of the press.

Each and every volunteer was young and robust. Wiley’s rationale was this: if even these vigorous, full-blooded young men could not tolerate these substances, then their harmfulness would naturally be proven.

During the trials, they lived in the “Science Boarding House”, carrying on their lives and work as normal. Their diets were strictly monitored, with three meals a day prepared by a dedicated chef. Wiley himself weighed the chemicals added to their daily food on a balance.

The test subjects and the control group were given strictly identical food and beverages, apart from the substance under trial. Before every meal, each volunteer had to record his weight, body temperature and pulse. They also carried collection jars for urine and faeces, which were promptly sent to chemists for analysis.

The first substance tested was borax, then in widespread use. Within days, the volunteers began losing weight. As the dosage increased, they developed symptoms including loss of appetite, a bloated feeling, persistent headaches and abdominal pain. In the sodium benzoate trial, only three lasted to the end; the rest fell gravely ill, suffering unbearable stomach pain, dizziness and weight loss. The formaldehyde trial left them all bedridden.

In the end, Wiley proved beyond all doubt that these substances were harmful to health.

America’s Gilded Age was a period of industrialisation and urbanisation, but also of the chemical and food-processing industries — and of food safety scandals erupting one after another. In the United States, “Swill milk” directly or indirectly caused the deaths of more than 8,000 infants. In Europe, milk adulterated with water, alum-laced bread and lead-contaminated sweets prompted Britain’s Adulteration of Food and Drink Act 1860. Yet efforts to enact food safety legislation in the US were relentlessly obstructed by corporate interests and repeatedly failed to pass Congress. That was precisely what made human self-experimentation with poisons necessary.

At last, on 30 June 1906, the United States passed the Pure Food and Drugs Act. Also known as the Wiley Bill after its principal author, its historical significance cannot be overstated. The Act not only set standards at the level of national regulation for food-related matters, but also laid down the core rules of modern food safety on a scientific and professional level. It has been drawn upon and cited by food safety legislation in the vast majority of countries around the world. China’s own Food Safety Law (2009) likewise incorporates these core food safety rules.

Illegal Additives That Defy Every Ban

Remember the first target of Wiley’s real-human poison trials — borax? Borax is incredibly versatile and useful, cheap and easy to get hold of. Apart from being toxic, it has absolutely no faults.

I just bought about half a kilo online for just over ten yuan. Of course, I’m not going to follow Wiley’s example and taste poisons myself — instead, I’m going to “set a poison trap”: steam a small potato, mix it with an equal weight of granulated sugar and an equal weight of borax, mash it into a paste and place it where cockroaches hang out. The aroma and texture of the potato, combined with the sweetness of the sugar, will lure cockroaches to call their friends over for a feast. After a pleasant, free-to-eat dinner party, the borax will wipe them out completely. For the next few months, no more worrying about cockroach nuisances, and as a bonus, the ants have dropped off a great deal too.

Borax is toxic and was first explicitly listed in China as a prohibited food preservative in 1978. In 2008, it was added to the List of Non-Edible Substances Potentially Illegally Added to Food. Yet even to this day in 2026, incidents of illegal borax addition keep occurring.

That’s because borax works like alchemy in food — it can alter the protein structure of rice and wheat products, meat and bean curd products. Add it to liangpi (cold noodle strips) or lamian (pulled noodles), and they turn silky-smooth, resistant to breaking and full of chew. Add it to meatballs or dried bean curd sticks, and they become springy and withstand prolonged boiling. The texture upgrades on the spot.

When it comes to illegal borax addition, rice and wheat products are the worst-affected category. Zongzi (sticky rice dumplings), changfen (rice noodle rolls), zongzi, noodles, dumpling wrappers, wonton wrappers, frozen dumplings and wontons — any of these could be affected. Unscrupulous traders even inject borax into pork to make the meat look brighter, feel smoother and stay fresh for longer.

Just in mid-August, a deli in Lianzhou, Qingyuan, Guangdong, was also caught adding borax to meatballs and bean curd rolls stuffed with meat. In these types of news stories, the people who appear on television are almost invariably small entrepreneurs, small proprietors and small traders with honest, guileless faces — the very people we pass on the street or bump into in the market every day.

Beyond borax, formaldehyde is likewise a colourless, odourless, endlessly versatile all-purpose substance — and a confirmed carcinogen. It is commonly used on frozen seafood, dried bean curd sticks and other dried goods, as well as bagged vegetables, mushrooms, fruits and other easily perishable goods for short-distance transport. Also to watch out for: sulphur dioxide used on rehydrated products (such as tripe, beef aorta and white fungus); industrial caustic soda and formalin used to rehydrate dried squid; malachite green and eugenol used during the transport and storage of live fish; nitrites used on bulk-sold cooked meat and pickled products…

Manufacturers don’t necessarily produce honestly in accordance with their ingredient lists, either. In a recent food safety spot-check, the State Administration for Market Regulation tested 2,325 batches of samples and 45 failed. Illicit use of additives was the most prominent issue, involving sweeteners, colouring agents, preservatives, bleaching agents and several other categories. For example, the synthetic colouring agents Brilliant Blue FCF and tartrazine were detected in dried wheat noodles; sulphur dioxide residues exceeded the permitted limit in five-spice pickled mustard tuber, lotus root and star anise; and cyclamate — which is explicitly banned nationwide — was detected in baijiu (Chinese spirits). There were also issues such as microbial contamination and excessive heavy metal levels.

Science and Skulduggery

In the food industry, the use of additives is no longer satisfied with merely fulfilling functions such as preservation and keeping things fresh — “Science and Skulduggery” can now conjure “delicacies” out of thin air.

Abe Tsukasa, who spent ten years at Japan’s largest food additive company and was hailed in the industry as the “Additive God”, documented in his book Food: The Truth Revealed a “meatball” he had created for a food company: the main ingredients were pulpy, sticky beef shreds that could only ever have gone into dog or cat food, ageing hens culled once they stopped laying (Abe’s own term was “junked chickens”), and textured soy protein. First, beef extract and other flavourings were added to establish the “beef ball” taste; lard and starch gave it a slick, smooth mouthfeel; a gelling agent and an emulsifier were added to facilitate large-scale mechanised production; a colouring agent fixed the colour, with an antioxidant to prevent fading; a preservative and a pH adjuster extended the shelf life; and then, topped with “tomato ketchup”, the creation became the “meatball” on the supermarket shelf. Real tomato ketchup is far too expensive, so the “ketchup” contains no tomato at all — it is blended from diluted glacial acetic acid, caramel colour, a colouring agent, an acidulant, a thickener and the like. In texture, colour and flavour it is indistinguishable from the genuine article; the only difference is the price, and that difference is worlds apart.

Abe Tsukasa turned a heap of waste into pure alchemy — not only did he hit upon a flavour that children adored, he also nailed the perfect texture: small children could chew it apart in two or three bites, and anyone who tried it was instantly won over. These “meatballs” were hugely popular among housewives, too — not just because they cost next to nothing, but because they came vacuum-packed and were ready to eat after a quick spin in the microwave, making dinner effortless.

Abe Tsukasa’s life took a turning point on his daughter’s third birthday. After years of relentless overwork, he came home early one day and found the meatballs he had developed sitting on the dinner table. Up to that moment, he had always been proud of the product, believing that turning waste materials into food was both environmentally friendly and a way to help housewives save money. But watching his own child eat them that day, he was plunged into self-reproach. He resigned from the food additive factory and began publicly exposing the inner workings of the food industry.

In later years, he often gave live demonstrations during lectures, with a large array of small bottles filled with “white powders” laid out before him. Joking all the while, he would spoon out the powders from dozens of bottles one by one, stir them together and pour the mixture into hot water — without a single drop of real pork-bone stock added throughout the entire process — and produce a bone broth for Kyushu-style pork-bone ramen that even local people would find familiar and delicious.

This phenomenon is by no means unique to Japan. Some of the chicken bouillon powder and beef stock powder on the market need not contain a scrap of chicken or beef. If you look closely at the ingredient lists on a considerable proportion of the food now sold in supermarkets, you will find what amounts to a veritable “Compendium of Additives” — much the same as what Abe demonstrated on stage.

Cumulative Effects

But don’t assume that legally approved food additives pose no risk whatsoever to your health.

Every single additive in the “meatball” developed by Abe Tsukasa was a fully compliant product — no illegal substances were involved; the quantity of each additive fell within permitted limits — nothing was exceeded; the meat raw materials were neither spoiled nor deteriorated, but simply offcuts and scrap left over from the processing of other meat products.

But he knew perfectly well that most current compliance dosages are derived from animal experiments on single additives in isolation — a “single metabolic safety line” — that takes no account of the cumulative effects and synergistic reactions produced when multiple additives enter the body simultaneously. Children’s metabolic organs are still developing; ingesting multiple additives at once not only exceeds their metabolic capacity and impairs physical growth and normal nutrient absorption, but may also disrupt neurological development and trigger allergic reactions.

Moreover, legal additives at legal doses may not remain legal forever. Food additives are typically rolled out by manufacturers to suit their production and sales needs first, then restricted or banned only after problems surface. Rules on food additive use vary from country to country and region to region. China’s beloved mooncakes, for instance, cannot be exported to the EU because dehydroacetic acid and its sodium salt (sodium dehydroacetate), so widely used in them, are comprehensively prohibited for food use across the EU. China itself has now drastically narrowed the permitted scope of use, and the substance is entering a countdown to a full ban.

There is a supposedly reasonable-sounding maxim: “Talking about harm without considering dosage is pure hooliganism.” Whenever a food safety scare strikes, experts and academics are sure to trot out this line, citing studies to argue that one would have to consume such and such a quantity before it could damage a particular organ. I instinctively recoil from the condescending professional superiority baked into it, and I would like to borrow the very same sentence structure to fire it back: “Deliberately pulling apart the cumulative effects and synergistic reactions between multiple harmful substances, cherry-picking a single metabolic safety line to ‘prove’ no harm exists — now that is the real hooliganism.”

“The dose makes the poison” is a core principle of toxicology, and it is also the go-to defence that manufacturers and sellers deploy with unfailing success whenever they face regulators or public opinion. People broadly accept this framing, and it is all too easy to extrapolate it to every other additive that touches daily life — to assume that as long as the dose is low enough, the harm can simply be disregarded.

Then there are endocrine disruptors — substances not directly added to food, but widely present in food-related containers and packaging, household cleaning products, non-stick pan coatings and so on. Research has found that such chemicals can exert effects on the human body at extraordinarily low concentrations, and are linked to reproductive damage, abnormal development in children and heightened cancer risk. Depending on the specific substance and the route of exposure, in certain cases the harm from low-dose exposure actually exceeds that of high-dose exposure.

Pharmaceuticals must undergo safety testing before being approved for market, and food safety is attracting ever greater scrutiny. Yet in virtually every country, chemicals containing endocrine disruptors need not demonstrate their safety before hitting the shelves. New varieties keep proliferating — manufacturers push them out first and deal with restrictions or bans only once problems emerge.

Take the Teflon coating developed by DuPont in 1938 — a material that first rose to prominence during the Second World War. After the war, its non-stick, heat-resistant properties were harnessed for everyday consumer use in non-stick pans, cookware and the like. Subsequent research, however, revealed that PFOA (perfluorooctanoic acid), a processing aid used in the manufacture of Teflon, is a highly hazardous persistent organic pollutant. Only after the International Agency for Research on Cancer classified it as a carcinogen did countries begin introducing regulations one after another; in 2023, China added PFOA (perfluorooctanoic acid) to the China Catalogue of Strictly Controlled Toxic Chemicals (2023). Today, PFOA (perfluorooctanoic acid) has been phased out by the major manufacturers of non-stick cookware.

Such examples are too numerous to list. In other words, through our own consumption and our very lives, we are all, unwittingly, taking part in one mass-scale human experiment after another.

28-Day Ultra-Processed Food Experiment

Just because something is sold everywhere doesn’t make it safe, and just because everyone eats it doesn’t make it harmless.

Dr Chris van Tulleken, a British doctor, carried out his own “Real Person Tastes a Hundred Poisons” experiment on his body for a BBC programme. Unlike Wiley’s design — precise measurements of “poisons” on a balance, complete with a control group — his approach was simply to “live an ordinary, normal life”. The core medical data, including blood tests and brain MRIs before and after the trial, were supervised throughout by experts from University College Hospital.

Chris was in good health, ate a balanced diet day to day, and rarely consumed ultra-processed foods. Once the trial began, he swapped his homemade oat porridge for boxed supermarket cereal with a strawberry yoghurt drink. Lunch became a convenience store sandwich and a microwaved ready meal; dinner was frozen pizza and chicken nuggets; and his snacks were energy bars and sugar-free cola. It sounds perfectly wholesome, yet that is precisely the horror of industrially produced food. In puffed cereal, real oats are just one ingredient among many; in strawberry yoghurt drink, milk is merely a minor player — the true stars are flavourings and syrups.

Chris developed constipation first, which soon progressed to haemorrhoids, because his diet now contained almost no natural dietary fibre. Then came the overheating, the excessive sweating, the restless sleep; then anxiety and irritability; then slower reactions, fading memory, a loss of patience with his children, a loss of enthusiasm for work…

At the end of the 28-day trial, Chris had gained 6.5 kg and developed fatty liver. The various additives had taken a toll on his gut, quite possibly because of those very additives. Animal studies have shown that the common emulsifiers found in everyday foods — soya lecithin, mono- and diglycerides of fatty acids, carrageenan, polysorbate-80, and the like — act like washing-up liquid for the gut: they erode the mucus layer, making it easier for bacteria to reach the intestinal epithelium. Long-term consumption may trigger low-grade chronic inflammation, increase intestinal permeability (so-called “leaky gut”), and is linked to obesity and metabolic syndrome.

The MRI scan also revealed that his brain had already begun to display the hallmark changes of addiction — almost identical to the patterns seen in the brains of people who are genuinely addicted. We have discussed the concept of the “Bliss Point” before: manufacturers calibrate the precise ratio of sugar, salt and fat to maximise the pleasure of eating, so that one never feels satisfied, even directly stimulating the release of dopamine. The human appetite becomes like a car with the accelerator slammed to the floor and the brake lines cut — not only can you not stop eating, but even after you have eaten your fill, you still feel you haven’t had enough.

Once Chris returned to a healthy diet, his weight came down and the unpleasant symptoms slowly receded. But the bad news was that his brain did not recover. In other words, although he could will himself to quit unhealthy, high-sugar foods, the addictive effects were still wired into his brain.

If You Can’t Trust Ingredient Lists

Just Cut Out All Additives

By now many people know to check the ingredient list before buying, but for every new trick there is a new counter-trick — ingredient lists, too, are quietly evolving.

“Clean label” is a word game some manufacturers play to exploit the information gap and mislead consumers with health claims. “Not fried” means the product is coated and soaked in oil before being baked at high temperature — it genuinely never went into a frying pan, but that does not mean it is free of oil or trans fat. The harmful reactions between starch and oil under high heat are no less present, and the average acrylamide content in some oven-baked “non-fried” crisps is actually higher than in deep-fried ones.

Some “0 added preservatives” products rely on excessive salt and sugar to achieve preservation. “0 added sugar” often merely means “0 sucrose”. More and more people now know that sugar harms health, but by splitting white sugar into a long list of differently named sugars — glucose syrup, crystalline fructose, concentrated fruit juice, and so on — each individual ingredient can be pushed further down the list, while the total added sugar proportion remains unchanged. In some products, total sugars still rank near the top of the ingredient list.

When “concentrated apple juice” and “fructose syrup” appear on an ingredient list, many people assume the “apple juice” option is the healthier choice. In reality, the juicing process strips almost all the dietary fibre from the fresh fruit, and after evaporative removal of water, fructose and glucose can account for 65%–72% of the concentrate — practically indistinguishable from fructose syrup. The same applies to other concentrated fruit juices.

Some manufacturers exploit regulatory gaps and use these word games to create a “clean ingredient list” illusion, even charging a premium on the basis of it. You can never outsmart the seller. If additives are so impossible to guard against, I might as well stop guarding — don’t eat them, don’t buy them, and peace of mind is assured.

I have always believed that “no additives” matters more than “organic”. When buying supermarket prepared foods, gimmicks like “organic” can be ignored entirely. No matter how organic the raw ingredients, once sodium stearoyl lactylate, calcium propionate, ascorbic acid, mono- and diglycerides of fatty acids, and butylated hydroxytoluene (BHT) are added, our lives are still at risk. And if organic produce is cooked with loads of fat and salt, doctored with flavourings and MSG, or drenched in heavily processed soy sauce, oyster sauce and bottled seasonings, it is far less reassuring than ordinary ingredients simply boiled or steamed clean and plain.

Here are two simple, easy-to-remember suggestions:

One: choose whole foods and avoid processed products. If you cannot handle raw ingredients directly, choose those closest to their original form. If you can buy flour and steam your own mantou buns at the weekend, don’t buy pre-made buns or bread. If you can buy prawns in the shell, don’t buy shelled prawns or prawn cakes. If you can buy a whole cut of meat, don’t buy patties or meatballs.

Two: steer clear of “crispy, jelly-like and flavouring-heavy” products. Taosu (traditional Chinese almond cookies) and pineapple cake both require large quantities of shortening, sending trans fat levels through the roof. Fruit and vegetable crisps and mushroom chips are mostly made by low-temperature vacuum oil-infusion and dehydration (also called low-temperature frying), with oil content exceeding 30% — the fruit and vegetables are mere window dressing. The gums and gelling agents in jelly desserts and ice cream offer zero nutrition and burden the digestive system; children with weak stomachs need to be especially careful. Strawberry-flavoured yoghurt contains no strawberry, grape-flavoured drinks contain no grape — they are almost entirely blended from artificial flavourings and colourings.

Key takeaway: choose whole foods; avoid anything crispy, jelly-like or heavy on flavourings.

No one wants to be a guinea pig for additive testing; no one is willing to be the human test subject, yet putting it into practice is often easier said than done. I have spent five years conducting a very timid experiment in Wicked Valley: cutting out additives entirely.

Practice has proved I can do it — and in truth, so can you.

– This is Foodthink’s 833rd original article –

Editor: Xiaodan

Layout: Minglin

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