Salt, soy sauce, honey, beer: Microplastics found throughout everyday Korean foods

"I thought I just had to watch out for plastic water bottles."

Salt is a staple found on tables across every culture and border — one of the oldest and most universal ingredients in human history.

Yet a growing body of research suggests that people are consuming something else along with their daily salt: microplastics.

In one domestic study analyzing multiple types of edible salt, researchers found that a single 1-kilogram bag contained roughly 1,190 microplastic particles.

A shopper browses pork belly and other meats at a hypermarket in Seoul. [Yonhap]

Salt is far from the only concern. Microplastics have been turning up in a widening range of foods sold in South Korea — soy sauce, fish sauce, salted seafood, seaweed, honey, beer and other beverages among them.

Chemical additives used in plastic manufacturing, including plasticizers, have also been detected in food ingredients. Avoiding microplastics entirely through everyday eating is becoming increasingly difficult.

Shoppers browse the aisles of a hypermarket in Seoul. [Yonhap]

A joint research team from Daegu University, the National Institute of Food and Drug Safety Evaluation and Hanyang University analyzed microplastic content in several types of edible salt — including sea salt, rock salt and lake salt. The team found that sea salt contained an average of 584.5 micrograms of microplastics per kilogram, according to environmental science circles Wednesday.

Of the microplastics detected in sea salt, 98.4 percent were polyethylene (PE), polypropylene (PP) or polyethylene terephthalate (PET) — materials widely used in containers, packaging and beverage bottles.

Shoppers browse the seafood section of a hypermarket in Seoul. [Yonhap]

A significant share of the particles were too small to see with the naked eye. More than 7.2 percent of the microplastics found in sea salt and rock salt measured smaller than 20 micrometers — roughly 0.02 millimeters. The findings were published last year in the international journal Food Chemistry.

A separate study counted microplastic particles rather than measuring their mass. Research conducted in 2023 by a domestic joint team including Korea University found approximately 1.19 microplastic particles per gram of sea salt — equivalent to about 1,190 particles in a standard 1-kilogram bag.

Microplastics are generally defined as plastic fragments smaller than 5 millimeters. They form as plastic products wear down or break apart, then spread through water, air and soil. Once released into the environment, they are extremely persistent.

Smaller particles are thought capable of crossing biological barriers and migrating into the bloodstream and body tissues. Microplastics have already been detected in human blood, lungs, liver, kidneys and brain. Recent studies have raised concerns about potential effects on immune response, inflammation, reproductive health and the cardiovascular system.

Concerns about microplastics have long centered on plastic packaging such as water bottles and beverage containers. But recent findings show the problem extends to the food itself.

Soy sauce, fish sauce, salted seafood, seaweed and everyday condiments like salt are no longer exceptions. The worry is no longer confined to specific packaged products — it now spans the full range of foods and drinks people consume daily.

The same research examined 90 products across eight food categories — including soy sauce, fish sauce, salted seafood, seaweed, honey, beer and other beverages — and found microplastics in every category. Solid foods contained up to 20 microplastic particles per gram; liquid foods contained up to 117 particles per liter.

Vegetables at a hypermarket alongside plastic plasticizer compounds. [Getty Images Bank]

The pathways through which microplastics enter food varied by product. Researchers identified multiple potential contamination sources, including the salt production process, beverage manufacturing and packaging, and the salt used in preparing fermented seafood and seaweed.

The plastic-related substances found in food ingredients go beyond microplastics alone. Chemical additives used in plastic manufacturing have also been detected across a wide range of ingredients — most notably phthalates, plasticizers added to make plastic soft and flexible.

Biomonitoring experiments conducted in 2023 and 2024 by the Work Environment Health Research Institute found at least one type of phthalate in 376 food ingredients sold in South Korea, spanning all categories including vegetables and eggs, according to results the institute published last year.

The vegetable section of a store in Seoul. [Provided by reader]

Phthalates were detected across all food categories — not only packaged, processed and meat products but also grains and vegetables. Total phthalate concentrations were highest in eggs, followed by dairy products and processed foods.

Choi In-ja, a researcher at the Work Environment Health Research Institute, said the team had originally planned to select 90 types of food ingredients but changed the criteria midway through analysis because phthalate contamination levels were far higher than expected. "We ultimately had no choice but to narrow the selection to 60 types," she said.

The findings suggest that food can be exposed to plastic-related substances at multiple points along the supply chain — from production and processing to packaging and delivery. That is why individual consumers cannot avoid microplastics and other harmful substances simply by choosing products carefully at the supermarket.

Microplastic fragments found on a beach. [Getty Images Bank]

Critics also note that consumers who want to reduce their plastic exposure have few alternatives.

A coalition of 17 domestic and international organizations — including Greenpeace, Green Korea United, the Korean Federation for Environmental Movement and the Work Environment Health Research Institute — surveyed 1,000 adults nationwide in June. Some 68.7 percent said they had no choice but to use single-use plastic packaging because most products they wanted to buy were sold that way. Respondents also identified packaging as the most urgent area for plastic reduction.

Microplastic fragments. [Getty Images Bank]

The government unveiled a plan in April to transition to a plastic-free circular economy, setting a target to cut the use of new plastic raw materials by more than 30 percent against projected waste levels by 2030. The plan also includes lightening delivery containers, restricting excessive packaging for courier shipments and expanding the use of reusable containers.

Environmental groups, however, argue that voluntary participation by businesses and consumers alone will not be enough to meaningfully reduce plastic use.

Greenpeace said in a statement that the government must deploy economic incentives and legally binding measures across the board, going beyond simple recommendations and voluntary action. The group also called for reinstating regulations on single-use items and making the use of reusable containers a legal obligation rather than a mere suggestion.

woo@heraldcorp.com