Formaldehyde is a toxic organic compound that exists in many types of food. Fruit and vegetables such as apples, bananas, carrots and spinach all contain formaldehyde. It’s also found in beef, poultry, fish, and coffee beans.
Although it’s illegal for manufacturers to use formaldehyde as a food additive, the substance is produced naturally in some foods as a byproduct of metabolic processes. The formaldehyde that’s naturally present in food is generally considered non-toxic because of the relatively low levels. However, formaldehyde can be notoriously harmful and even deadly at high concentrations.
Continue reading to learn more about the type of foods that contain formaldehyde, as well as the other products that formaldehyde is used in.
In this post:
What foods contain formaldehyde?
Formaldehyde is found in both fresh and processed food products including meat and poultry, fish, some fruits and vegetables, and coffee.
Meat & poultry
Fresh meat and poultry usually contain formaldehyde as a natural byproduct of metabolism. One comprehensive study on naturally-occurring formaldehyde in food found poultry typically contains 8.2 parts per million, while beef contains 8.5 parts per million. 
Fish
Formaldehyde is naturally present in the tissue of marine and freshwater fish as a byproduct of the breakdown of trimethylamine oxide (TMAO). A 2017 study found the average formaldehyde levels in fish were as high as 39.68 mg/kg, although the concentration varies depending on the species.
Fruits
Many fruits also contain formaldehyde as a natural byproduct of chemical breakdowns. Some fruits that have relatively significant amounts of formaldehyde are bananas (16.3 mg/kg), pears (38.7 mg/kg), grapes (22.4 mg/kg), and apples (22.3 mg/kg). 
Coffee
While there’s only a trace amount of formaldehyde in coffee beans, this can become concentrated when the beans are processed. There’s also a significant difference between brewed and instant coffee, as shown by a quantitative analysis. Instant coffee was found to contain a higher concentration of formaldehyde (10-16.3 ppm) compared to brewed coffee, which only registered 3.4-4.5 ppm.
What is formaldehyde made of?
At room temperature, pure formaldehyde is a colourless, highly-toxic, pungent gas. It has the chemical formula CH2O and the structural formula H−CHO. In gaseous form, it spontaneously polymerises into paraformaldehyde. This is the reason why formaldehyde is stored as a solution in water (known as formalin). You can read more about what formaldehyde is made of here. 
Is formaldehyde toxic?
Formaldehyde is toxic because it can cause cell death. Exactly how this happens isn’t yet clear, but it’s thought formaldehyde interacts with cell membranes, which then disrupts normal cell functions. Highly-concentrated formaldehyde can also deactivate and denature proteins.
Formaldehyde can cause serious health issues, including pulmonary reaction, at a concentration of 50 ppm. It becomes highly toxic and life-threatening at a concentration of 100 ppm.
What else is formaldehyde used in?
As well as being naturally present in food, formaldehyde is produced industrially for a wide range of applications. Some of the other products that contain formaldehyde are:
- Cosmetic supplies – formaldehyde is used in small amounts in certain cosmetic products as a preservative. However, some people are sensitive to the chemical and it may cause an allergic reaction.
- Synthetic fabrics – the fabric industry uses formaldehyde to improve the wrinkle resistance of textiles, especially those made from cotton. Synthetic fabrics are also treated with urea-formaldehyde resins to make them perspiration-proof, mildew-resistant, moth-proof, and stain resistant.
- Wood products – formaldehyde is mainly used as a component of resins or glue products that are important in the manufacture of plywood, particleboard, and medium-density fibreboard.
Formaldehyde is used in resins - Dishwashing liquids & clothes softeners – formaldehyde is also used to manufacture dishwashing liquids and fabric softeners, where it acts as an antibacterial agent and preservative.
You can read more about the other uses of formaldehyde here.
What does formaldehyde do to your body?
Even at very low concentrations, formaldehyde can irritate your skin and cause allergic reactions in anyone sensitive to the chemical. 
Inhaling low concentrations of formaldehyde can easily irritate the mucous membranes in the respiratory tract, while higher concentrations can lead to shortness of breath, wheezing, and possible death.
What is a safe level of formaldehyde in the home?
Formaldehyde occurs naturally and can be found in many household products. Although it’s considered a highly toxic substance, there is a safe level of formaldehyde exposure that our body can tolerate. According to various sources, the formaldehyde-safe threshold is 0.1 ppm (100 ppb). Allergic reactions may occur beyond this threshold.
Summary
Formaldehyde is an organic compound that occurs naturally in many foods including apples, bananas, pears, spinach, carrots, beef, poultry, fish, and coffee beans. It’s produced as a byproduct of metabolic processes. Although food contains relatively low levels of formaldehyde, high concentrations of the compound can cause severe health issues. Formaldehyde is also produced industrially for a range of applications such as particle wood and fertiliser manufacturing.
