Sea moss, a dried seaweed often soaked and blended into a gel, surged in popularity during the COVID-19 pandemic as consumers sought foods believed to boost immunity and improve health. But little research has examined whether commercial sea moss products are safe to eat.
New research from Cornell AgriTech, published in the November 2026 issue of the Journal of Food Protection, begins to fill that gap. The studies are among the first to examine both the microbial safety of commercial sea moss products and how consumers commonly prepare sea moss gel at home.
The research was led by Ann Charles Vegdahl, an extension associate whose work focuses on helping food manufacturers produce safe foods. Questions about sea moss kept coming, but there was little science to guide answers.
“We get a question about sea moss at least once a week,” she said. “And we usually had to say, ‘sorry, we don’t have any answers for you, because there’s no data.’”
The project was sparked by a product recall she noticed about three years ago.
“I saw there was a recall on sea moss, and I realized no one had ever looked into the product,” Vegdahl said.
She secured funding from the U.S. Department of Agriculture’s National Institute of Food and Agriculture and launched the research.
What's Actually in the Package
In the study, Vegdahl’s team purchased 66 sea moss products, including 53 dried products and 13 gels, from online retailers such as Amazon and Etsy. Researchers screened the products for bacteria, yeast, mold and heavy metals and measured physical characteristics such as acidity, sugar content and moisture.
The results revealed wide variation in physical characteristics across products.
The team also found a range of microbes, including presumptive Bacillus and Staphylococcus, and, less frequently, organisms in the same families as Salmonella, Escherichia, Listeria and Vibrio.
“We screened for these organisms but didn’t confirm active pathogens, so we can’t say the products are unsafe,” Vegdahl said. “But it is concerning, especially for a finished product, to have such high levels of microbes.”
Researchers detected arsenic, cobalt and mercury in dried sea moss products, while gel products were largely free of those contaminants. Arsenic and cobalt fell below detectable limits, and mercury was present only in trace amounts. Because seaweed readily absorbs substances from the water in which it grows, heavy metals remain a known concern worth monitoring.
The findings serve as a reminder that “just because something is natural doesn’t necessarily mean it’s safe,” Vegdahl said.
Lessons From 112 YouTube Videos
Because most sea moss gel is made at home or by very small producers, with no standardized recipe, Vegdahl’s team also wanted to understand how consumers are preparing it. As part of a separate study, researchers analyzed 112 YouTube videos to identify common preparation practices.
Researchers found wide variation at nearly every step.
Most videos recommended soaking the sea moss (91%) and blending it (94%), but preparation methods differed substantially, particularly in water-to-sea moss ratios and soaking times.
“People do it by feel,” Vegdahl said. “They just throw it in and blend it.”
About half the videos recommended refrigeration, while nearly one-third offered no storage guidance. Basic food-safety practices were rarely visible on camera. Only a small fraction of videos showed gloves, hair restraints or handwashing.
Vegdahl identified the soaking step, often lasting 12 to 24 hours, as the most critical control point and a stage where harmful bacteria could potentially grow.
“If someone asked us for advice right now, we’d tell them to soak it under refrigeration,” she said, “because we know refrigeration slows microbial growth.”
Guidance for a Growing Market
Vegdahl is quick to acknowledge the limitations of the research. She did not know the origin of each product, and several may have come from a single supplier and been repackaged under different labels. In addition, the microbial screening identified potential organisms rather than confirmed pathogens.
Determining whether the products can cause illness would require a challenge study, in which researchers intentionally introduce pathogens to evaluate their survival.
Her advice to small producers hoping to sell sea moss commercially is to seek expert guidance before bringing products to market.
“Before you start commercializing a product, reach out to a Process Authority, someone who can validate your recipe,” she said.
Ultimately, Vegdahl said this fast-growing market needs more than research alone.
“The industry generally doesn’t know what to do,” she said. “We need to generate the data and then create resources for both consumers and the regulators inspecting these facilities, so everyone knows what safe looks like.”
CHRISTINA SZALINSKI is a freelance writer for the College of Agriculture and Life Sciences.
