Tea Bag Manufacturers Respond to Microplastic Particle Study

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Glatfelter filter paper selection (Photo credit: Glatfelter)
Glatfelter filter paper selection (Photo credit: Glatfelter)

Tea industry suppliers rushed to defend the publicly malignedtea bag following widespread media coverage of a research paper that revealed heat-sealedpyramid bags made of nylon and PET release billions of nanoplastic particlesduring a five-minute steep.

“The levels of nylon and polyethylene terephthalate (PET)particles released from the teabag are several orders of magnitude higher thanplastic loads previously reported in other foods,” according to the McGillUniversity study. Researchers tested leachate from teabags used by four popularsupermarket teas. The peer-reviewed study, published in the journal EnvironmentalScience & Technology, concluded that “at brewingtemperature (95 °C) a single tea bag releases approximately 11.6 billionmicroplastics and 3.1 billion nano-particles into a single cup of the beverage.”The tea bags were sliced open to remove the tea but a control demonstrated nodifference in the amount of leachate compared to uncut bags.

Suppliers explain that compostable bioplastics, while moreexpensive, are viable alternatives to traditional plastics. Biodegradableplastics decompose by the action of living organisms, usually microbes. Thesemicroorganisms give off carbon dioxide, water and biomass under industrialcomposting conditions that require temperatures of at least 60oC. Tomeet European Union standards tea bags made with bioplastics must break down inless than 12 weeks.

In contrast, long-polymer plastics including polyethylene, polypropylene, polystyrene, poly(vinyl chloride) and poly(ethylene terephthalate) degrade into smaller and smaller fragments (nanoplastic) that are not biodegradable. Some plastics made from petroleum, such as PBS (polybutylene succinate) are biodegrade and some plastics that originate from renewable biomass such as polyethylene and Nylon 11 are non-biodegradable.

There is no lower limit to the size of nanoplastic particles but these are generally measured in micrometers. There are no known ill-effects from ingesting what amounts to 60 micrograms – 60 millionths of a gram of plastic released by teabags, but consumers expressed concern, contacting their favorite brands for assurance. PET and nylon are certified as food-grade, a standard that limits degeneration to 10 milligrams per square meter of surface area in contact with foods. It is not known how much nanoplastic is in the environment.

Since the brands were not named the immediate response bysuppliers was “our tea is not packaged in nylon or PET.”

Commentsby Eliot Jordan, vice president of tea at Mighty Leaf are typical: “We’vereceived a number of questions about the safety of our tea pouches in responseto recent articles on the CBC News and CNN websites.  We want to assureyou that at Mighty Leaf Tea, the quality and safety of our tea is our greatestconcern.  The study cited in the article did not test Mighty Leaf Teapouches or the materials they are made of.  Mighty Leaf Tea pouches aremade from a 100% polylactic acid (PLA) woven yarn.  The PLA is made fromthe fermentation of sugar milled from corn. In addition, our tea pouches aremade with good manufacturing practices and comply with all applicable foodsafety regulations.”

Tea bags made of nylon and PET when viewed under an electron microscope revealed high levels of microplastic, and even smaller nano-plastic particles. (Diagram by LM Hernandez et all, McGill University)

Aneta Aslakhanova, global marketing director, at Newby Teas (UK) Ltd., wrote, “For us the focus in the last five years has evolved from ‘best packaging’ to ‘less and safe packaging’.”

“We have always used biodegradable materials in the bags themselves. All Newby teabags and pyramid bags are plastic-free. Fully biodegradable, our Silken Pyramids are made from corn starch while our Classic Teabags are made from a mixture of wood pulp and abaca which is a natural plant fiber,” she wrote.

Sharyn Johnston, founder of the Australian Tea Masters, uses an advanced Japanese material instead of plastic and Nylon bags "so our health concerns regarding contamination could well and truly be behind us."

Woventea bags made of synthetic polyester and nylon materials used in making themesh pyramids “represent approximately 5% of the total teabag materialsmarket,” according to Helsinki-based Ahlstrom-Munksjö, a leading manufacture ofteabag materials. The company does not use PET or nylon, relying instead on abio-plastic made from PLA (polylactic acid) derived from corn starch orsugarcane. The company also produces a fully compostable and biodegradable teaand coffee filter with PLA as the heat-seal fiber.

StuartNixon, vice president, beverage & casing business at Ahlstrom-Munksjö wrote,“Although traditional heat-sealable, ‘string & tag’ and BioWeb materialswere not part of this micro-plastic study, Ahlstrom-Munksjö will in the comingweeks investigate if there is any release of microplastic particles fromtraditional heat-sealable, string and tag type and BioWeb filter materials thatit produces.”

Terranova, a large filtermanufacturer in Barcelona, said concerns about non-compostable plastics led thefirm to develop cellulose and abaca filters. Heat seal versions contain PLAfrom vegetal origin. “We do not use any PET or Nylon in any of our filter paperproducts,” wrote Pere Paris, regulatory affairs and food contact manager.

Dr.Jerry Burch, product compliance manager at Glatfelter Composite Fibers BusinessUnit, wrote, “The presences and ingestion of microplastics in the human bodyand any potential health implications are a relatively new subject.”

Hecited following statements:

  • The World Health Organization has recently statedthat microplastics are increasingly found in drinking water, but there is noevidence so far that this poses a risk to humans.
  • The European Food Safety Authority has stated thatmicroplastics are “unlikely to pose a health risk to humans.”
  • The German BfR found that microplastic particlesless than 1mm are completely excreted with “no damaging effects shown on theintestinal tissue or other organs” based on a 2013 study of animals “fedvarious microplastic particles over 28 days at levels well above realistichuman exposure scenarios.”

“Recentstudies have identified that microplastics can enter the body. Key healthorganizations have acknowledged that human ingestion of microplastics is anarea where much more research is needed to provide a full risk assessment,”writes Burch. As a responsible supplier, Glatfelter will continue to researchand evaluate the issue, he said, adding, “There is no indication of any healthconcerns related to the use of Glatfelter’s teabag paper.”

Theleast expensive pyramids are costly at $0.01-0.03 each and difficult to pack,requiring machinery to operate at slower speeds 6,000 bags per hour compared toconventional bagging machines that produce 24,000 bags per hour.

Around 90% of modern tea consumption consists of low-quality cheap teabags, observes Aslakhanova. “As a premium tea supplier, it is obvious that the consumer behavior needs to change,” she wrote.

“In the short-term, we motivate consumers to switch to qualityloose leaf tea which is the most sustainable option. Sounds like a lot of workfor many, but in reality, it takes perhaps a minute or two more than a teabagand helps to save the planet.” 

Source: EnvironmentalScience & Technology