When Peter Molan, a now-retired scientist and academic in New Zealand, began researching the properties of honey more than 30 years ago, there was little demand for a type made by bees that pollinated the flowers of the native manuka bush.

“It used to be thrown away,” he said. “If you taste genuine manuka honey, it’s got a very strong flavour and people didn’t like it.”

Then Molan discovered there was something special about manuka honey. It appears to have antibacterial properties, unlike other honeys in the world, and some studies suggested it could heal wounds and help boost the immune system. (Specifically, the antibacterial property found in other honeys comes from hydrogen peroxide, which is broken down quickly in the body, whereas the non-peroxide form found in manuka honey isn’t.)

Many of the health claims are still being tested, but once manuka’s supposed healing powers became known outside New Zealand, it moved from the margins of the honey world into a globalised, multimillion-dollar industry. Celebrity endorsers like tennis player Novak Djokovic and actress Scarlett Johansson only added to its appeal.