It now seems common knowledge that plastic and food, especially when exposed to high temperatures, do not make good company. When heating food in the microwave in plastic containers, substances with health effects may be released and it is best to always use glass containers. However, in many kitchens there is an exception that can be dangerous.
These are black plastic kitchen utensils: spatulas, skimmers, ladles and tongs which are generally made of nylon. This plastic melts at 220ºC, so the utensils are resistant when, for example, they are used to stir boiling broth, which does not exceed 100ºC. They are also used because they do not damage non-stick pans, unlike metal utensils.
However, we have repeatedly found that these utensils can melt when, for example, left in a hot pan. This melted plastic should not come into contact with food, but recent studies indicate that some nylon utensils may have other serious potential problems.
The problem of flame retardant materials
Flame retardants are chemicals added to plastics, textiles and foams to reduce their flammability and delay the spread of fire. In the case of plastics, these retarders are incorporated during the manufacture of the material, either through additives mixed directly into the polymer or through chemical processes that integrate them structurally. Its function is to inhibit or slow down the combustion process by intervening in the chemical reactions which allow the flames to propagate.
There are different mechanisms by which these retarders act on plastics. Some substances release gases that cool the surface of the plastic when they burn, thereby reducing combustion. Other compounds create a carbon layer that insulates the material from oxygen and heat, slowing inflammation. There are also retardants that work by diluting the oxygen around the burning material, preventing the fire from spreading quickly.
The first flame retardants, polychlorinated biphenyls, were banned in the 1970s in the United States when they were found to be toxic, and internationally since 2001. The European Union began banning flame retardants brominated, also toxic, in 2004, expanding restrictions in 2008.
However, these toxic products can be returned to certain products thanks to a process that we consider to be very beneficial: plastic recycling. A recent study, carried out by environmental research organization Toxic-Free Future, in collaboration with the University of Amsterdam, found that 85% of more than 200 products analyzed contained high levels of brominated flame retardants. These in turn came from recycling plastics from electronic waste, such as TV boxes and other devices.
The products were purchased in stores of all kinds in the United States, but the majority were manufactured in China and therefore distributed to other international markets. The same study warns of the risk that kitchen utensils and containers made from these recycled plastics, when heated, could release these harmful substances into food.
Alternatives to plastic
One of these retardants, called decaBDE, was completely banned in 2021 by the US Environmental Protection Agency after being linked to cancer, endocrine and thyroid problems, fetal development and neurobehavioral function and children, as well as toxicity to the reproductive and immune systems. People with the highest levels of this substance in their blood were about 300% more likely to die from cancer than those with the lowest levels, according to a study published this year of 1,100 people.
Despite these restrictions, decaBDE was found in 70% of samples analyzed in the Amsterdam study, at levels between five and 1,200 times higher than the European Union limit of 10 parts per million. Based on exposure to contaminated black plastic cooking utensils, such as spatulas and ladles, study researchers estimated that a person could be exposed to an average of 34.7 parts per million of decaBDE every day. The study only looked at black plastics, so it could not determine whether other colors of plastics might also be exposed.
Brominated flame retardants are of particular concern, not only because of their toxicity, but also because they tend to accumulate in living tissues and can remain in the body for years.
The scientists’ recommendation is to replace plastic kitchen utensils with stainless steel utensils. This change may be incompatible with using nonstick pans, but these pans can also be problematic, especially when the coating deteriorates, and there are safer options like traditional stainless steel or cast iron pans. These pans are also scratch resistant and compatible with steel utensils.
In addition, it is advisable to avoid black plastic in other objects that come into contact with food, such as the trays in which prepared or home-delivered food arrives, which should never be used in the microwave, because the heat promotes the filtration of chemical substances in the microwave food with which it is in contact.
If any of the plastic utensils have melted while cooking (a common occurrence), you should avoid eating the food that was prepared with it and throw it away in a clean place where it will hopefully be recycled into something who won’t. no need to be recycled with food.
