Disposable Food Boxes Leach Carcinogenic Toxins
Core Tip: Leftovers are taken away in disposable plastic food boxes, takeout is served in disposable plastic food boxes, and food for takeaway is also packed in disposable plastic containers—when eating this kind of boxed meal, have you ever thought that what you might be swallowing is the food box itself?
Recently, reporters purchased the most common types of disposable plastic food boxes from the market for testing and found that when exposed to ethyl acetate, some boxes would instantly melt. Chemical experts point out that the byproduct of all cooking wine and vinegar is ethyl acetate. When placed in disposable plastic food boxes, the plastic from the box can easily migrate into the food and be ingested by humans.
■ Doubt
The Takeout Box Became a Bit Soft
Recently, a takeout box made citizen Mr. Shan feel quite "uncomfortable." The incident happened on May 12th. Mr. Shan was treating friends at a hotel and, as usual, took the unfinished food home in a takeout box. The box provided by the hotel for free was a disposable plastic one. The particular Mr. Shan took a closer look, "It was a disposable plastic food box. I had a moment of suspicion, but it felt quite thick, and it was even labeled 'eco-friendly food box,' so I agreed to use it."
Mr. Shan took the four boxes of food home. The next day at lunchtime, he was surprised to find that the bottom of the disposable plastic food box had become a bit soft, completely different from the thick feel before packing. This left Mr. Shan very puzzled. "It's a plastic box, not a paper one, so logically, it shouldn't get soft just from being soaked in food soup. And when I poured the food out and held it up to the light, it seemed to have gotten thinner."
Mr. Shan looked up information online and was surprised to find many netizens had encountered similar situations. Claims like "disposable plastic food boxes melt when they come into contact with oil," "disposable food boxes melt when they come into contact with vinegar," "using disposable plastic food boxes can cause cancer," and "takeout can lead to food poisoning" made him increasingly fearful the more he thought about it: "If the plastic food box can actually dissolve into the food, isn't eating a boxed meal the same as eating the food box itself?"
■ Investigation
"Three No" Plastic Food Boxes Flood the Market
Over several days, reporters investigated the catering industry on the island and found that disposable plastic food boxes are very common for meals, fast food, packing, and takeaway. They come in all sorts of styles—some transparent, some opaque, some labeled "eco-friendly food boxes," and others "biodegradable food boxes." According to catering hotels, these disposable plastic food boxes are mostly purchased wholesale from the Fushun Road Wholesale Market.
On the 14th, reporters went to the kitchen and catering supplies wholesale section of the Fushun Road Wholesale Market. Just as the hotels said, every stall there sold disposable food boxes. "Sold by the pack, 100 in a pack, in various sizes." A wholesaler said while pointing upwards. Reporters looked up and saw over a dozen samples of disposable plastic food boxes of different materials and models hanging in a row. The types of boxes seen in hotels and restaurants were mostly all available here.
Upon close inspection, reporters found that some of these disposable plastic boxes were marked "PS," some "PP," and some had no markings at all. On the shelves, the boxes sold in packs of 100 were only wrapped in a single plastic bag. There was no information on the manufacturer's name, address, or brand, no indication of raw materials or ingredients, and let alone a QS quality mark.
"What is this made of?" a reporter asked. "It's just plastic, but we don't know exactly what kind," the wholesaler claimed. According to the vendors, the wholesale price for these boxes is very cheap: large-sized disposable plastic boxes for 0.15 yuan each, medium-sized "PP" plastic boxes for 0.10 yuan each, and "PS" plastic boxes for 0.12 yuan each.
■ Explanation
The Plastic Food Box Might Have Been Dissolved
Why exactly do disposable plastic food boxes become soft? Reporters, like Mr. Shan, consulted various experts and the preliminary conclusion they reached was: the plastic food box may have encountered a soluble organic substance.
What substances can dissolve a plastic food box? Wang Jianhua, a professor at the Shandong Entry-Exit Inspection and Quarantine Bureau's Testing Center, explained that "PP" refers to polypropylene plastic, and "PS" refers to polystyrene plastic. Foamed plastic is composed of various components such as polystyrene, polyurethane, polyvinyl chloride, and polyethylene. "These are all high-molecular organic substances. If they dissolve, disintegrate, or migrate, it's because they have encountered an organic solvent. The possible organic substances in general cooking, besides oils, are ethyl acetate."
■ Disclosure
Cooking Wine and Vinegar Form Ethyl Acetate
"In cooking, the byproduct of commonly used cooking wine and vinegar is ethyl acetate," said Professor Wang Jia, a doctoral supervisor at the College of Chemistry and Chemical Engineering at Ocean University of China. The main component of cooking wine and alcohol is ethanol, and the main component of vinegar is acetic acid. When ethanol and acetic acid react, they form ethyl acetate, also known as "acetic ethyl ester."
"When we cook, we usually add some cooking wine and vinegar to make the food smell good. This fragrance is the effect of ethyl acetate," Professor Wang said. Ethyl acetate is an organic substance that can break down the benzene rings in high-molecular materials like PS and PP, causing them to dissolve and disintegrate. "Without a doubt, as long as there is ethyl acetate and it comes into contact with a dissolvable food box, a local reaction will definitely occur, causing substances in the plastic to migrate and transfer into the food, and then enter the human body along with the food," Professor Wang stated.
Other chemical experts expressed concern, pointing out that organic compounds are complex, and the components of cheap disposable plastic food boxes are unclear. Once they come into contact with substances like ethyl acetate or oils, other harmful substances may be generated, posing an even greater risk to human health.
■ Experiment
Upon Pouring Ethyl Acetate, the Food Box Instantly Melts
Reporters purchased the two most common types of food boxes from the Fushun Road Wholesale Market: one transparent "PS" box and one opaque "PP" box. They also bought a white plastic bowl with no markings. Foamed plastic food boxes were once popular, but reporters couldn't find any on the market, so they bought a sheet of foamed plastic of the same material instead.
Subsequently, reporters purchased "ethyl acetate" solvent, a colorless transparent liquid, from a chemical equipment store. Reporters used the purchased PS box, PP box, plastic bowl, and foamed plastic as experimental subjects to see what reaction would occur when they came into contact with the ethyl acetate solvent.
First, reporters poured a small spoonful of ethyl acetate solvent into the transparent, disposable PS plastic food box. A shocking scene occurred: the moment the ethyl acetate solution touched the box, the liquid instantly turned white and bubbly, and a "hissing" sound was heard. The bottom of the box instantly disappeared, and the ethyl acetate liquid flowed onto the floor. There was also a small amount of white, flocculent substance in the solution, which completely dissolved and disappeared after 2 seconds.
Next, reporters dripped ethyl acetate solvent onto the foamed plastic sheet. With just a tiny drop, a large hole was immediately "burned" into the foamed plastic sheet. The 3cm thick sheet was "burned through" in an instant, and the hole continued to expand. The plastic sheet shrank severely, reacting violently with the solvent and emitting a large number of bubbles. After 2 seconds, only a small corner of the foamed plastic sheet remained.
The reaction of the disposable PP plastic food box with ethyl acetate was not as violent. However, after about 40 minutes, reporters found that the originally firm, thick bottom of the box had become very soft and had a distinct physical curve. The unmarked plastic bowl's bottom also became soft after 2 hours, showing a physical curve.
The once perfectly fine disposable plastic food boxes were completely transformed upon encountering the ethyl acetate solvent. The experimental process could truly be described as "shocking to behold." Professor Wang Jia, a doctoral supervisor at the College of Chemistry and Chemical Engineering at Ocean University of China, stated that in daily cooking, the amount of cooking wine and vinegar used is not large, and the concentration of ethyl acetate produced is limited. It won't dissolve or disintegrate the plastic food box as dramatically and violently as pure ethyl acetate solvent. "However, if a food box can be dissolved by ethyl acetate, it certainly does not meet the usage standards for food boxes."
■ Reminder
It's Better to Use Fewer Disposable Plastic Food Boxes
On the 15th, reporters learned from the city's industrial and commercial department that the once-popular foamed plastic food boxes have been phased out of the market. According to law enforcement officials, the raw material of foamed plastic food boxes contains harmful substances. When used to hold high-temperature, high-oil foods, these harmful substances can easily leach out, migrate, and condense onto the food, entering the human body and causing harm.
Furthermore, disposable food boxes made of foamed plastic are difficult to degrade and will not rot for many years. When burned, they release a large amount of harmful gases, causing serious environmental damage. Therefore, as of 2001, China has completely banned the production, sale, and use of foamed plastic tableware.
The migration of plastic into food is strictly controlled in imported and exported food. According to Wang Jianhua, an expert from the Shandong Entry-Exit Inspection and Quarantine Bureau's Testing Center, the EU limits the migration amount of plastic from boxes in imported and exported food.
Upon checking information, reporters learned that China's current national standard for disposable plastic food boxes is the "General Technical Requirements for Disposable Plastic Tableware," which was officially implemented on December 1, 2009. Before 2009, China did not have a national standard for disposable plastic tableware; instead, each company had its own enterprise standards. However, this sole national standard only sets limits on the content of heavy metals, organophosphorus pesticide residues, fluorescent substances, and toluene diamine in disposable plastic food boxes. It does not set a limit on the migration amount of the plastic itself.
Therefore, experts remind the public that while disposable plastic food boxes are convenient, most are low-quality, cheap boxes, and some are even made from recycled plastic. These non-compliant boxes contain harmful substances such as industrial calcium carbonate residue, heavy metals, paraffin, benzene, etc., which seriously harm human health.
If the plastic components of low-quality disposable food boxes encounter high temperatures, high oil content, or ethyl acetate, harmful substances can easily transfer into the food. Therefore, the use of disposable plastic food boxes should be reduced or avoided.