How Microplastics Are Reshaping Global Food and Health Risks

Plastic pollution is no longer an environmental problem happening somewhere else. It is moving through the systems that grow food, carry water, feed livestock and package what people eat, and increasingly, researchers are finding its microscopic traces inside the human body.

The warning comes from"You Are What You Eat: Microplastics, One Health, and Our Global Food System," a comprehensive review published in Sustainability by University of Minnesota researchers Gerald Shurson and Mary Kosuth. Drawing on 197 systematic, scoping and critical reviews, alongside original studies and policy evidence, the authors connect plastic production, environmental contamination, agriculture, food safety, animal health and human exposure within a single One Health framework.

The study does not claim that everyday exposure has been proven to cause a defined set of human diseases. It argues that contamination is already pervasive, the pathways are interconnected, and regulators still lack standard methods, safe exposure thresholds and coordinated policies to manage the risk.

Plastic's Convenience Has Become Its Long-Term Liability

Modern food systems rely heavily on plastic because it is cheap, light, durable and adaptable. It protects food from contamination, extends shelf life, reduces transport weight and supports irrigation, greenhouse production, animal-feed storage and affordable distribution.

About 40% of global plastic use is linked to food packaging, while roughly 12.5 million tonnes are used annually in agriculture, livestock production, forestry and fisheries. Plastic appears in mulch films, irrigation pipes, fertilizer coatings, pesticide containers, fishing gear, silage bags and food-processing equipment.

These applications deliver genuine benefits, making abrupt elimination unrealistic. The problem is that plastic's useful life is often measured in minutes or months, while its environmental life can last for decades or centuries.

Global plastic production surpassed 400 million tonnes in 2022, and the cumulative stock produced has reached an estimated 11 billion tonnes. Only around 9% is recycled. Much of the remainder is landfilled, incinerated, buried, exported or released into the environment.

Sunlight, heat, abrasion and chemical processes gradually break larger items into microplastics smaller than five millimetres and nanoplastics smaller than one micrometre. These particles travel through wind, rain, rivers, wastewater, soils and food webs. Nanoplastics are especially difficult to study because they are too small to see and may cross biological barriers more readily.

The review also places plastics within the fossil-fuel transition. Around 99% are produced from fossil-fuel feedstocks. As transport and electricity systems reduce their reliance on oil, petrochemical demand may become increasingly important to the industry. Plastic pollution is therefore not only a waste issue; it is also tied to climate policy, industrial strategy and continued fossil-fuel production.

From Farm Soil to Dinner Plate, Plastic Keeps Circulating

The food chain is where multiple contamination pathways converge. Agricultural fields receive plastic through degraded mulch, greenhouse films, irrigation equipment, coated fertilizers, pesticide containers and contaminated water. Sewage sludge and biosolids can return particles captured from urban wastewater to farmland, turning an otherwise valuable nutrient-recycling practice into a route for recirculating contamination.

Once present in soil, microplastics may alter structure, water movement, nutrient cycling and microbial activity. Nanoplastics may enter plant roots and move through internal tissues, creating potential pathways into edible crops.

Animals are exposed through contaminated feed, water, air and soil. The review cites studies detecting plastic particles in livestock feed, chicken meat, milk and eggs. Aquatic exposure is even more extensively documented: research across hundreds of marine and freshwater species has found plastic ingestion in fish and shellfish.

Contamination can increase after harvest. Processing equipment, storage materials and packaging may shed particles into food. Heating containers, tearing seals and twisting bottle caps can release fragments, while plastic additives may migrate under certain temperature and contact conditions.

The evidence table on page 21 captures the breadth of the problem. Microplastics have been reported in fish, chicken, eggs, milk, honey, fruit, vegetables, rice, wheat, sugar and salt. They have also been found in groundwater, tap water, bottled water, soft drinks, beer, wine and takeaway food.

Water may be one of the most important exposure routes because it is consumed directly and used throughout farming and food processing. One study cited in the review detected microplastics in 93% of bottled-water samples across multiple countries, although concentrations varied sharply.

Plastic particles may also carry more than plastic. The review notes that 16,325 chemicals are potentially associated with plastics; 4,219 are known to be hazardous, while hazard data are unavailable for more than 10,700. Particles can additionally adsorb pesticides, heavy metals, PFAS, antibiotics and persistent organic pollutants from their surroundings.

This creates a wider One Health concern. Plastic surfaces host microbial biofilms known as the plastisphere, where bacteria may exchange antibiotic-resistance genes. Experimental evidence suggests that microplastics may not merely transport resistant organisms but create conditions that accelerate resistance. If confirmed in real-world settings, plastic pollution could amplify the antimicrobial-resistance crisis.

The Exposure Is Real, but the Health Risk Is Still Hard to Measure

Researchers have detected microplastics or nanoplastics in human blood, lungs, liver, kidneys, heart tissue, placenta, breast milk, semen, urine and faeces. Their presence shows that particles can enter the body and reach multiple biological compartments.

Estimates of how many particles people consume vary enormously. One widely cited analysis placed annual ingestion from food at 39,000 to 52,000 particles, rising to 74,000–121,000 when inhalation is included. Bottled-water consumption may add substantially more, but the figures depend heavily on analytical methods, particle-size limits and assumptions.

Animal and cell studies associate exposure with inflammation, oxidative stress, intestinal-barrier damage, hormonal disruption, reproductive harm, metabolic changes and neurological effects. Nanoplastics often appear more biologically active because they can enter cells more easily.

Yet the evidence has major limitations. Many experiments use pristine polystyrene spheres, even though real-world exposure involves weathered particles of different sizes, shapes and chemical compositions. Some studies use doses far above environmental levels, while most examine short-term exposure rather than the chronic, low-level exposure people experience over decades.

Human observational studies are often small and cannot establish causation. A diseased organ might retain more particles, rather than particles having initiated the disease. There is still no internationally accepted safe threshold for microplastics in food or water.

The Solution Must Begin Before Plastic Becomes Waste

The review challenges the belief that recycling can solve a problem driven by continuously rising production. Many plastics cannot be recycled repeatedly. Materials lose quality and are often downcycled into products that eventually reach landfills or incinerators. Recycling processes can also release particles and emissions. Meanwhile, high-income countries have often exported plastic waste to countries with weaker collection and treatment systems, shifting health and environmental costs onto communities least responsible for producing the waste. For developing countries, this creates a double burden: rising domestic plastic consumption and imported waste, combined with limited wastewater treatment, laboratory capacity and municipal infrastructure.

• Governments should focus on source reduction, product redesign and producer responsibility. Avoidable single-use plastics should be restricted, chemical additives disclosed, and manufacturers required to finance collection, treatment and safe disposal across the product life cycle.
• Agricultural authorities should monitor high-risk inputs such as plastic mulch, polymer-coated fertilizers, sewage sludge, irrigation water and animal-feed packaging. Food-safety regulators need stronger surveillance of packaging, processing equipment and drinking water.
• Wastewater investment is critical. Conventional and optimized systems can remove a large share of microplastics from water, but the particles then accumulate in sludge and must be managed safely.
• Biodegradable alternatives may help, but they are not automatically harmless. Some decompose only under industrial conditions and may still fragment in ordinary soil or water. Alternatives must be assessed across their full life cycle to avoid replacing one poorly understood risk with another.

The review's greatest strength is its systems perspective: it shows that plastic released in one sector can travel through several others before reaching consumers. Its breadth is also a limitation. It is a comprehensive critical synthesis rather than a formal risk assessment, and the evidence it brings together varies in quality.

Despite the limitations, the key findings are relevant. Once microplastics are dispersed through soil, water and food systems, large-scale removal becomes technically difficult and potentially impossible. Prevention is therefore more realistic than cleanup. The world does not need to wait for every disease mechanism to be conclusively mapped before acting. A proportionate response would reduce unnecessary production, redesign essential uses, strengthen research standards and protect communities carrying the greatest disposal burden.