A team of researchers has filed a complaint against Tesco, saying its “biodegradable” teabags do not fulfil that claim following an experiment that involved burying them in soil for a year to see what happened.
Dr Alicia Mateos-Cárdenas from University College Cork (UCC) set out to investigate how well teabags advertised as biodegradable broke down. She buried 16 Tesco Finest Green Tea with Jasmine pyramid teabags in garden soil. However, when the teabags were dug up, they remained intact.
She checked them at three weeks, just over three months, six months and 12 months, and found no change. She flagged her paper to two researchers at the UCC’s Environmental Law Clinic, who have now collectively reported the supermarket to a consumer protection watchdog in Ireland.
The complaint says that a customer would reasonably expect a product labelled as biodegradable to break down in the open environment within a year, or sooner. The Tesco Finest Green Tea with Jasmine pyramid bags showed no signs of degradation after 12 months due to the type of bioplastic they are made from, according to the complaint sent to the Competition and Consumer Protection Commission (CCPC).
The company has recently changed suppliers but the academics argue that the teabags are still made from the same plant-based bioplastic, called polylactic acid (PLA).
Tesco said that the packaging clearly states that its teabags are not approved to be disposed of in soil or home composting, but need to be industrially composted (having been put in a local council food waste bin). A Tesco spokesperson said: “We strongly dispute the claims made in this study and believe that the findings are misleading. The method of decomposing teabags used in the study does not reflect the on-pack advice we give customers.
“All our own-brand herbal teabags have been certified as industrially compostable, which means they can be disposed of in food caddies and council collections, biodegrading with organic matter through in-vessel composting. We do not advise customers to dispose of these teabags in home compost bins or soil.”
The researchers say Tesco should change “biodegradable” to “plant-based” or “compostable” if they cannot rot down in gardens or compost bins. “It is fair to assume that any PLA teabag will not biodegrade in the open environment,” said Mateos-Cárdenas, from the School of Biological, Earth and Environmental Sciences at UCC, who published a paper on the biodegradability of teabags in Frontiers in Bioengineering and Biotechnology. Her findings formed the basis of the subsequent complaint.
“The fact that they come from another supplier is meaningless,” she said. “We have proven that Tesco is misleadingly selling their teabags using greenwashing practices. We are hoping that the CCPC will urgently act.”
Given that the teabag showed no sign of disintegration after a year, it is reasonable to believe it could persist in the soil for much longer, the researchers argue. If the average consumer has two cups of tea a day, they could have more than 700 teabags in their home compost bin or in the garden after one year. This renders Tesco’s claim “not only false, but also misleading and unsubstantiated” under Irish and EU consumer protection legislation, the complaint says.
The researchers want investigators to look into the broader issue of retailers making misleading claims about materials biodegrading, with such claims being “rife”.
“It is incumbent upon Tesco and others to ensure that their products live up to their advertised claims,” said Mindy O’Brien, coordinator of Voice of Irish Concern for the Environment, who is calling on the CCPC to investigate the claim to avoid further greenwashing. “Now more than ever, consumers are motivated to purchase a product that appears to be more sustainable. There is no room for false or misleading green claims.”
The complaint follows research led by Prof Mark Miodownik from University College London which found most plastics marketed as “home compostable” don’t actually work, with as much as 60% failing to disintegrate after six months.
“The results do not surprise me,” he said, commenting on this latest research, which he was not involved in.
“If the product hangs around for years before biodegrading, which is the reality for many products labelled biodegradable, they are part of the problem not the solution. There are innovative companies out there trying to make a difference, but they don’t use the term biodegradable because they know it’s code for greenwash.”
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