The curious case of green cheese

A cheese farm in Vermont unlocked an evolutionary mechanism in fungi

- ELIZABETH PRESTON

TWO SIGNIFICANTTHINGS happened on a day in 2016 when a group of scientists travelled from Massachusetts to a cheese farm in Vermont.The first was a marriage proposal. The second was the scraping of samples from the rinds of 50 blue cheese wheels.The importance of those samples, though, wouldn’t become clear for many years. Researchers have used the proposal-day material as a time capsule to prove that a mould species in the cheese cave rapidly evolved, transforming a signature cheese before its makers’ eyes.

The cheese, called Bayley Hazen Blue, is aged in underground vaults for three to fourmonths while wild microbes from the air colonise its rind. The end product used to be mottled with vivid green. Over a couple of years, those cheeses changed from green to white. Lab experiments showed that a mould species in the cave had mutated, losing its ability to make pigment — like cave-dwelling animals that evolve in the dark to be albino.

The results were published last month in the journal Current Biology.