Five new varieties of Penicillium roqueforti, the fungus used to make blue cheese, have been created, possibly helping to secure the future of Stilton, Roquefort and other cheeses.
The work could also lead to new strains of the fungus that further reduce the risk of cheese toxins, as well as others that may have pharmaceutical applications.
P. roqueforti is used all over the world to produce blue cheese鈥檚 distinctive coloured veins and flavour. Prior to the new study, P. roqueforti strains could be grouped into four populations two used in cheese production and two found in silage, timber and spoiled food.
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The two blue cheese populations, known as Roquefort and non-Roquefort, are both experiencing genetic bottlenecks. They primarily reproduce asexually, which means that harmful mutations can accumulate in the population.
Without new varieties of Penicillium roqueforti, the production of blue cheese may end up in trouble, says at Paris-Saclay University.
鈥淲ithout diversity, there is no possibility to adapt,鈥� she says. 鈥淭his means we cannot generate new strains to have new kinds of blue cheeses, or cope with any change that may occur in terms of parasite, virus or heat or anything.鈥�
Giraud and her colleagues have created five new crosses with parents from both the cheese and non-cheese strains of P. roqueforti.
She says that the new crosses have a range of promising properties. 鈥淸There are] new types of colour and metabolic activities, so we can produce new types of products, more or less blue, milder or stronger,鈥� she says.
While the toxin level in blue cheese is so low that it doesn鈥檛 impact human health, developing new crosses could further reduce the risks of blue cheese toxicity, say the researchers.
Existing P. roqueforti strains can already be used to produce some medically useful compounds, such as mycophenolic acid, an immunosuppressant used to prevent organ transplant rejection, and the anti-tumour compound andrastin A. The study showed that the new crosses had the potential to increase the production of these compounds.
, an independent dairy culture expert, says that not all loss of genetic diversity is bad, and the existing P. roqueforti strains are useful because they have lost undesirable traits. 鈥淭he cultured microorganisms we use in making cheese today have been carefully chosen so that the cheeses always turn out the way we want them to,鈥� he says.
But these new varieties may still be useful in cheese production, he says. 鈥淒ifferent cheese-makers might use different strains to achieve different flavour, texture or appearance, or even to develop completely new cheese types.鈥�
at the University of Queensland, Australia, says he is doubtful that the industrial process is threatened by the loss of genetic diversity in blue cheese moulds, but the new crosses are 鈥渆xciting鈥� nonetheless.
鈥淧roducers could almost dial up their list of desirable characteristics 鈥� more or less colour, faster or slower growth rate, acidity differences,鈥� he says.
bioRxiv
