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Scientists Take the “Blue” Out of Blue Cheese

Dr Paul Dyer holding petri dishes, standing next to a bulk of blue cheese.
Credit: the University of Nottingham
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Blue cheese doesn’t have to be so… blue. According to new research, it can be yellow, white, orange and green, all while maintaining the same texture and flavor, more or less.

Scientists at the University of Nottingham made the discovery after inhibiting the fungus Penicillium roqueforti (P. roqueforti), which is responsible for the maturation of the cheese.

The researchers found that, by deleting a few of the fungus’s genes, they could alter its biochemical effect on the cheese, leaving the food white, yellow-green, red-brown-pink or dark brown.

Remarkably, all these variants tasted more or less the same, according to chemical analysis – although volunteers who actually ate the cheeses did purport flavor differences.

The findings are published in the journal NPJ Science of Food.

Not so blue

P. roqueforti is used worldwide in the production of blue-veined cheese such as Stilton, Roquefort and Gorgonzola.

Using a combination of bioinformatics, targeted gene deletions and heterologous gene expression, the researchers discerned how the fungus interacts with the cheese.

They found that the biochemical pathway gradually turns the white dairy food a yellow-green, which becomes a red-brown-pink, then dark brown, light blue and finally dark blue-green.

The team then used genetic modification techniques to block this biochemical pathway at certain points to create new colored cheeses.

After putting samples of the cheeses through lab diagnostic equipment, they found that none significantly differed in taste.

“We found that the taste was very similar to the original blue strains from which they were derived,” said Paul Dyer, a professor of fungal biology at Nottingham University. “There were subtle differences but not very much.“The interesting part was that once we went on to make some cheese, we then did some taste trials with volunteers from across the wider university, and we found that when people were trying the lighter colored strains, they thought they tasted more mild.”

He added, “Whereas they thought the darker strain had a more intense flavor. Similarly, with the more reddish brown and a light green one, people thought they had a fruity tangy element to them – whereas according to the lab instruments they were very similar in flavor. This shows that people do perceive taste not only from what they taste but also by what they see.”

Dyer and his team say they will now look at working with cheese makers in Nottinghamshire and Scotland to further produce the new color variants. A university spin-out company has also already been established to see if the strains can be commercialized.

“Personally, I think it will give people a really satisfying sensorial feeling eating these new cheeses and hopefully might attract some new people into the market,” Dyer added.

Cleere MM, Novodvorska M, Geib E, Whittaker J, Dalton H, Salih N, Hewitt S, Kokolski M, Brock M, Dyer PS. New colours for old in the blue-cheese fungus Penicillium roqueforti. NPJ Sci Food. 2024. doi: 10.1038/s41538-023-00244-9

This article is a rework of a press release issued by the University of Nottingham. Material has been edited for length and content.