Cutting boards are often made of wood or plastic and are found in homes as well as commercial kitchens. Cutting on them causes defects in the boards, and plastic cutting boards might be a source of microplastic particles due to this wear and tear. For example, materials such as polypropylene and polyethylene could shed nano- and micro-sized particles. To understand whether this poses a risk, it is necessary to understand how many particles are produced during use under realistic circumstances and whether the produced particles are toxic.
Syeed Md Iskander, North Dakota State University, Fargo, USA, and colleagues have investigated how many microplastic particles are released from chopping boards and studied the impact of chopping styles and board materials, as well as the potential toxicity of the produced particles. The team performed chopping experiments with different persons using the same steel knife to chop on polyethylene, polypropylene, or wood chopping boards. They performed experiments with just the boards, as well as with carrots to simulate real-life chopping. After each experiment, the knife and the board were rinsed with water that had been previously tested for microplastics, and the produced microplastic particles (or wooden microparticles) were filtered out to collect them. The particles were imaged using microscopy and weighed.
The team found that the mass of polyethylene microplastics was significantly affected by the chopping patterns of the individuals. The chopping board material also affected the mass of microparticles released during chopping: The wooden chopping board controls showed a higher release of wooden microparticles by mass compared to the polyethylene and polypropylene chopping boards. Chopping carrots on polyethylene chopping boards was associated with an increased release of microplastics compared to chopping on an empty board, which the researchers attribute to greater pressure during chopping. When it comes to shape and size, spherical microplastics smaller than 100 μm were found most often. Overall, the team estimated that food preparation could expose a person to tens of millions of microplastic particles from chopping boards each year.
The researchers also performed a preliminary toxicity study of polyethylene microplastic particles. They did not find significant effects on the viability of mouse fibroblast cells after 72 h. However, they point out that further investigations of health implications are needed and that microplastics could accumulate in the body and release monomers or additives during cooking. Overall, plastic chopping boards could be a major source of microplastics in food, and measures to limit exposure could be useful.
- Cutting Boards: An Overlooked Source of Microplastics in Human Food?,
Himani Yadav, Md Rakib Hasan Khan, Mohiuddin Quadir, Kelly A. Rusch, Partho Pritom Mondal, Megan Orr, Elvis Genbo Xu, Syeed Md Iskander,
Environ. Sci. Technol. 2023.
https://doi.org/10.1021/acs.est.3c00924
