A form of mould that grows on discarded food has been shown to radically alter its taste, allowing food that would otherwise be thrown away to be eaten in a new form.

Neurospora intermedia, an orange fungus cultivated from the discards of soy milk production, has been used for centuries to make oncom, a traditional food in Java, Indonesia.

at the University of California, Berkeley, and his colleagues worked with chefs at Michelin-starred restaurants in New York and Copenhagen to develop new foods using the fungus. Some of the results are now appearing on their menus, including a cheesy-tasting toast made from stale bread and a sweet dessert made from sugarless rice custard.

Around a third of food globally is wasted, with discarded produce responsible for around 8 per cent of greenhouse gas emissions. Repurposing it into new kinds of food that can be eaten, known as upcycling, can reduce the climate impact of food production by diverting waste from landfills, while also enhancing food security, says Hill-Maini.

His team has shown that N. intermedia can flourish on at least 30 types of agricultural waste, including tomato pomace and banana peel, without producing toxins.

The fungus can transform indigestible plant waste into nutritious food in around 36 hours. “It seems to have a unique trajectory on waste, from trash to treasure,” says Hill-Maini.

When the team asked Danish consumers to try oncom for the first time, people consistently rated it above 6 on a scale of 1 to 9 and described the taste as “earthy and nutty”, he says.

Hill-Maini collaborated with Rasmus Munk, who runs the Alchemist restaurant in Copenhagen, and Andrew Luzmore of Blue Hill at Stone Barns, a restaurant in Pocantico Hills, New York, to develop foods based on the fungus.

At Alchemist, N. intermedia was used in a dessert of jellied plum wine with unsweetened rice custard, which was left to ferment for 60 hours. This process altered both the aroma and taste “in quite a dramatic way”, according to Munk.

“I found it mind-blowing to suddenly discover flavours like banana and pickled fruit without adding anything besides the fungi itself,” he says. “Of course, all of our wild shots don’t work out, but when they do, they can produce quite revolutionary results.”

The chefs involved hope that by demonstrating what upcycled food can do at the highest level of gastronomy, the concept will gain commercial appeal.

“We are just at the beginning stages of unlocking its full potential,” says Hill-Maini.