Much has been written in the past several months about the contamination of Dhaka’s food supply. From meeting minutes published by the Institute for Public Health in March to the anti-formalin bill passed through parliament on July 1, the news, social media, and civil society have been frantic with a mixture of fear, anger, and confusion.
The public’s concern is not misplaced. Reliable scientific evidence - though anecdotal - indicates widespread food safety issues at every level of the value chain from production, processing, and transportation to wholesale, retail, and end consumption.
Unfortunately, the response to this public health crisis by the news media, government, and civil society, though well intentioned, has been largely uninformed. Rumours and pseudo-scientific claims are recited as undisputed truths, while scientists are regularly misquoted or, worse, ignored entirely.
An excellent example of the public misunderstanding of this crisis is the current “war on formalin,” which focuses on the sensational as opposed to the practical issues regarding the presence of formaldehyde in food and its illegal and dangerous use as a preservative.
Formalin, a mixture of between 30% and 40% formaldehyde in water and methanol, is hazardous to human health. Acute consumption of one ounce can kill a human, while some evidence shows lower but chronic exposure may increase rates of some cancers.
Interestingly, citizens of Bangladesh and every other nation in the world safely eat, drink, and breathe non-negligible amounts formaldehyde every day.
Formaldehyde is a component of many biological processes and is present at varying levels in all fruits and vegetables, many fish, and the human body. Formaldehyde is an essential chemical in the human body and serves as a building block for biosynthesis of larger molecules.
Formaldehyde is also a by-product of combustion reactions, including car engine exhaust, camp fires and cigarette smoke, all of which citizens of Dhaka inhale regularly.
One of the most common industrial chemicals globally, formaldehyde is used to manufacture and process furniture, particle board, curtains, toilet paper, nail polish hardener, cleaning products, insecticides, and various other consumer goods that we use safely on a daily basis.
How can something so common in our diet and environment also be deadly? More importantly, what are the safe levels of formaldehyde and formalin, and how can its presence be detected and exposure limited?
After several meetings and extensive correspondence with experts at the UN-FAO, Institute for Public Health, and BUET, and a review of the available scientific literature, below are answers to some basic questions that can help guide your decision-making about the food you eat and your exposure to formalin and formaldehyde.
What are safe levels of formaldehyde and formalin exposure?
Formaldehyde content is generally measured in three ways, milligrams per meter cube (mg/m3) for air and gases, milligram per litre (mg/l) for liquid, and milligrams per kilogram (mg/kg) for solids; mg/l and mg/kg are also expressed in parts per million (ppm).
The following is a breakdown, based on available data, of safe levels of formaldehyde and formalin exposure. It is important to note that the formaldehyde does not accumulate in human tissue over time, but that children and elderly people are much more vulnerable to the chemical, as are individuals with existing health conditions like asthma.
Formaldehyde inhalation
According to the American Chemistry Council, inhaled formaldehyde gas rapidly breaks down in the body from a gas into the soluble form of formaldehyde and then changes into formate in the nose and respiratory tract. Formate is either used as a building block chemical for the body to make larger chemical molecules or broken down into carbon dioxide, which is exhaled in breath.
Indoor air normally contains about .05ppm formaldehyde, while urban outdoor air is composed of as much as .02ppm. These levels vary depending on industrial density, general air quality, traffic, and other factors. Humans can begin to detect the presence of formaldehyde around .75ppm, when it has a distinct noxious chemical smell, while concentrations of 1ppm can lead to nasal and eye irritation, nausea, dizziness, and headaches.
The American Occupational Safety and Health Administration says exposure to more than 2ppm should be limited to 15 minutes to prevent irreparable damage, while prolonged exposure to concentrations between 1 and 2ppm has been shown to affect lung function.
Several cohort studies have linked long-term exposure to moderate levels of formaldehyde with some forms of cancer. However, individuals who are not exposed occupationally to elevated formaldehyde levels are not significantly at risk for long-term formaldehyde-related health issues.
Oral formalin consumption
Less is known about the effects of oral exposure to formalin. Just as inhaling low levels of formaldehyde is normal, we consume naturally occurring formaldehyde contained in fresh and perfectly safe fruits, vegetables, and fish on a daily basis.
Apples, grapes, and green onions can contain upwards of 20mg/kg, pears up to 60mg/kg, and shitake mushrooms more than 400mg/kg when dried. Meat and poultry contain up to 40mg/kg while some fresh seafood have 100mg/kg or more when processed. These levels depend on many factors, including the species, region, and season.
If large doses are deadly and small doses are part of a balanced diet, what exactly is a safe amount of formalin to consume on a daily basis? The WHO Tolerable Daily Intake (TDI) for formaldehyde is 0.15mg/kg body weight.
That means an individual who weighs 70kg can safely consume up to 10.5mg of formaldehyde per day with no discernible short or long-term effects on health. To reach this level, a person may have to eat several kilograms of high-formalin food every day.
Is it possible to determine whether formalin has been added to my ‘fresh’ produce?
Detecting formaldehyde in liquid or solid sample is not straightforward, since there are several detection techniques for formaldehyde that also indicate the presence of aldehydes, ketones and alcohols. The precise formaldehyde content of food can be determined in a laboratory using relatively sophisticated hardware possessed by only a handful of public and private institutions in Bangladesh.
However, there has been no large-scale study to determine ranges of natural formalin in Bangladesh’s fruits, vegetables, and fish. It would therefore be difficult to determine whether formalin had been added unless the tested levels were off the charts.
The testing kits used by the government are designed as simple binary indicators of the presence or absence of any formaldehyde gas. A positive result does not mean formalin was added illegally.
Much of the fresh produce and fish available will naturally contain enough formalin to register a false positive, and markets in Bangladesh are filled with other potential sources of formaldehyde, including cigarette smoke, car exhaust, and laminated wood.
There is no reliable way to determine if the positive result of the test is caused by naturally occurring formaldehyde, environmental pollution, or illegally added formalin. The testing kits also detect other chemical compounds, such as ethylene, methanol, ethanol, and carbon monoxide, and inaccurately report them as formaldehyde.
Therefore, the “testing kits” used by the retailers and the government to reassure customers and prosecute suspected contaminators are not very useful in determining whether formalin has been illegally added as a preservative.
If I suspect my produce to be contaminated, is there some way I can remove it?
If formalin has been added to produce and you happen to eat it (without washing in hot water first), you will almost definitely be able to tell. Common symptoms of acute exposure include immediate inflammation of the nose, eyes, and throat, dizziness, nausea, vomiting, diarrhoea, and abdominal pain.
All fruits, vegetables, and fish should be washed in hot water (500C) for 15 minutes, regardless of whether or not formalin contamination is suspected. If hot water is not available, the food item should be thoroughly washed in running water. Formalin easily dissolves in water, so a thorough washing should remove any residue. Cooking will also eliminate any formaldehyde present, as it evaporates very easily.
Where can I purchase produce that is not contaminated with formalin?
The best strategy for finding fruits and vegetables that are not contaminated with illegally added formalin is to purchase from vendors who have farmed the produce themselves. Formalin is most often added by traders looking to minimise wastage as they transport produce to market.
Another good strategy for seafood is to buy flash frozen products from reputable exporters. Bangladesh’s frozen seafood industry is well regulated by international inspectors and is booming as a result of its good quality. More and more of these exporters are marketing their product domestically as well.
Several companies, including Direct Fresh (cofounded by the author), have begun to prioritise transparent supply chains to ensure the quality of the produce, even when the result is marginally more expensive than the market rate. Investigate these suppliers for yourself, and regardless of their claims, be sure to wash your produce in hot water (500C) or running tap water.
How can the government address the critical public health issue of formalin in the food supply?
The government can only do so much. First, it must stop depending on the use of unreliable testing methods that risks fining and imprisoning innocent vendors of uncontaminated fruit, vegetables, and fish. For the confirmatory testing, the government should rely on proper laboratory analysis.
Second, investigators must focus on identifying liquids sprayed onto produce and prosecute vigorously any vendor who is caught in the act of spraying liquids found to contain formalin or other harmful chemicals. This will require a huge increase in due diligence at the regional farm and market level, such as the regular presence of investigators to observe markets that take place around the country at dawn every morning.
Third, formalin and other toxic chemicals should only be available to the licence holders and appropriate users. By ensuring a transparent supply chain, officials from different government agencies and law enforcement authorities can greatly control the improper use of formalin and other hazardous chemicals.
This issue must also be addressed by consumers, who demand beautiful, undamaged produce with a long shelf life, but are also incredibly sensitive to price. Unless consumers are willing to pay more for increased wastage and can accept shorter shelf-life and less “pristine” looking produce, there is little the government can do to change behaviour.
The best strategy is to be personally diligent in where you procure and how you prepare your fruits, vegetables, and fish.
