Plastics pervasive across entire food chain

A study led by CSIRO has found that micro and nanoplastics are pervasive in our food supply and may be affecting food safety and security on a global scale.

The research builds on past studies, which primarily tracked plastics in fish, finding that plastics and their additives are present at a range of concentrations not only in fish but in products including meat, chicken, rice, water, takeaway food and drink, and even fresh produce.

Jordi Nelis, CSIRO analytical chemist, food safety specialist and lead author of the paper, said there are many pathways for these plastics to enter the human food chain, such as animal ingestion, but one of the main ways is through food processing and packaging.

“Fresh food for example can be plastic-free when it’s picked or caught but contain plastics by the time it’s been handled, packaged and makes its way to us,” Nelis said.

This plastic may be deposited by machinery, cutting boards or plastic wrapping.

Another pathway for contaminants to enter the agriculture system is through biosolids sourced from wastewater treatment. Though biosolids are a rich fertiliser for agricultural land, they can contain plastic particles from many sources, such as the washing of synthetic clothing.

These particles could build up in the soil and change the soil structure over time, affecting crop production, food security and ecosystem resilience. Plastic materials can ‘trick’ the good bacteria in the soil into thinking they are the roots of plants, leading to plants ending up with fewer of the nutrients they need.

The study also discussed how functional additives in plastics can leach into the environment, contaminating food supply. Additives that make plastic flexible or resistant to UV radiation, for example, can include flame retardants, heavy metals, phthalates, hardeners or other ethical compounds.

Currently, there are no definitive studies that demonstrate micro and nanoplastics in the environment cause harm to humans; however, more research is needed to fully understand their health effects.

Research is also needed to better understand the effects of plastics and their additives on food safety and security to develop better analytical techniques to monitor, assess and establish safe levels in food, drinking water and agroecosystems.

“The key missing information is determining safe levels of microplastics. We currently don’t know exactly what the microplastic flux through the food system is or which levels can be considered safe,” Nelis said.

He said there are things that consumers can do to help reduce micro and nanoplastics from cycling through the environment.

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