STiR coffee and tea magazine

44 STiR coffee and tea / Issue 6, 2019 (December / January 2020) 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) particles less than 1mm are completely excreted with "no damaging effects shown on the intestinal tissue or other organs," based on a 2013 study of animals "fed various microplastic particles over 28 days at levels well above realistic human exposure sce- narios." "Recent studies have identified that microplastics can enter the body. Key health organizations have acknowledged that human ingestion of microplas- tics is an area where much more research is needed to provide a full risk assessment," writes Burch. As a responsible supplier, Glatfelter will continue to research and evalu- ate the issue, he said, adding, "There is no indication of any health concerns related to the use of Glatfelter's teabag paper." Promising alternatives "Woven tea bags made of synthetic polyester and nylon materials used in making the mesh pyramids "represent approximately 5% of the total teabag materials market," according to Helsinki-based Ahlstrom-Munksjö, a leading manufacturer of teabag ma- terials. The company does not use PET or nylon, relying instead on a bio-plastic made from PLA (polylactic acid) derived from corn starch or sugarcane. The company also produces a fully compostable and biodegradable tea and coffee filter with PLA as the heat-seal fiber. Stuart Nixon, vice president, beverage & casing business at Ahlstrom-Munksjö wrote, "Although traditional heat-sealable, 'string & tag' and BioWeb materials were not part of this micro-plastic study, Ahlstrom-Munk- sjö said it will investigate if there is any release of microplastic particles from traditional heat-sealable, string and tag type and BioWeb filter materials that it produces." Terranova, a large filter manufac- turer in Barcelona, said concerns about non-compostable plastics led the firm to develop cellulose and abaca filters. Heat seal versions contain PLA from vegetal origin. "We do not use any PET or Ny- lon in any of our filter paper products," wrote Pere Paris, regulatory affairs and food contact manager. Polyhydroxyalkanoate "PHA [polyhydroxyalkanoate] is defi- nitely a potential candidate for a biode- gradable tea bag," writes Joe B. Grubbs III, Ph.D., senior polymer scientist at Danimer Scientific. PHAs are made by bacterial fermentation in the natural world (as opposed to synthetic polyester). The PHA produced depends on what the bacteria are fed. Scientists have al- ready identified more than 150 different polymer structures. Unlike PLA, PHAs are biodegrade at ambient temperatures, and sink in water which facilitates its anaerobic biodegradation in sediments. Danimer is working with Nestlé to de- velop PHA water bottles that dissolve in seawater. "We have grades that would meet the requirements for tea bags and also would withstand boiling water. However, this is not an application we have tar- geted with our current grades of PHA," said Grubbs. "I can't make a claim about leachates as we have not done any spe- cific testing with tea bags and leachates. However, we do know that PHA is more hydrolytically stable than PLA. "PHA will break down in a lot of dif- ferent environments per all of our certifi- cations but we have not specifically tested it in the [human] body. It is a test that we would be open to doing but have not reach a point where we have or needed to test yet," he said. The least expensive pyramids are costly at 1-3 US cents each and difficult to pack, requiring machinery to operate at slower speeds 6,000 bags per hour com- pared to conventional bagging machines that produce 24,000 bags per hour. Around 90% of modern tea con- sumption consists of low-quality cheap teabags, observes Aneta Aslakhanova, global marketing director, at Newby Teas (UK) Ltd. "As a premium tea supplier, it is obvi- ous that the consumer behavior needs to change," she wrote.

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