Core to the research is the finding that important food-related bacteria react to the compounds produced by fungi in the rind. These compounds are released into the air. This triggers certain bacterial species to grow and others to be inhibited. This balance is essential for developing certain cheese flavours.
The chemical released by fungi are volatile organic compounds (organic chemicals that have a high vapour pressure at ordinary room temperature). These are related to the secretion of enzymes, which function to break down amino acids in order to produce acids, alcohols, aldehydes, amines, and various sulphur compounds. Each of these biological products adds to the flavour, complexity and aroma of cheese.
Examples of the types of cheeses where these interactions help produce are Camembert, Blue cheese and Limburger, each of which is characterized by a ‘signature’ smell.
More detailed examinations revealed how different volatile organic compounds altered the expression of different genes in different bacteria. This included those genes that affect the way bacteria metabolize nutrients.
The researchers see the findings as a step forwards in understanding the elements that make-up the cheese microbiome. Understanding this more fully can assist with enhancing the flavour and quality of different cheeses.
According to lead researcher Professor Benjamin Wolfe the outcomes “show that cheese microbes can use these aromas to dramatically change their biology, and the findings’ importance extends beyond cheese making to other fields as well.”
Furthermore, greater insights into bacterial-fungal interactions and of microbiomes in general can assist other fields, such as seeking advances in agriculture so that soil quality and crop production can be improved. Perhaps also in medicine to help manage the spread and control of diseases.
The research is outlined in the journal Environmental Microbiology. The research paper is titled “Fungal volatiles mediate cheese rind microbiome assembly.”
