Microbes in cheese: the bacteria that bring unique flavours and texture
If you want to make the best cheese you need a little helping hand from some friendly bacteria, but how do farmers make the microbes that gives their dairy product the edge?
We have always lived in the company of countless microbes, but our relationship with these invisible fellow-travellers is evolving rapidly. Just a few decades ago, they were widely associated with filth and disease—or at best, seen as silent observers whose fate had little to do with humanity’s success or failure. But advances in microbiology are toppling this view of the world around us, and not just in the realms of the human gut and healthy soil. It turns out that natural microbial communities play a pivotal, and until recently undreamt-of, role in raw-milk cheesemaking as well.
Of course, it’s possible to make cheese with milk that’s been stripped of its microbial character, either through intensive use of chemicals during the milking process or through pasteurization. Such milk must be reseeded with commercial cultures—strains of bacteria and often fungi—before it can be made into cheese. This approach is efficient: commercial cultures are cheap and widely available, and using them it is possible to produce mountains of cheese from commodity milk pooled from hundreds of different farms. Cheeses with consistent flavours, driven by the same few strains of selected bacteria, are both cheap and dependable at scale.
But for small farmers who do not have access to the same economies of scale, making cheese that takes its flavour from ingredients used by big factories doesn’t add up. Instead, farming milk to encourage a diverse and healthy microbiome, and then putting those endemic microbes to work making cheese, has the potential to introduce unique flavours that cannot be mimicked by a factory.
Read more about cheese:
- Does eating blue cheese contribute to antibiotic resistance?
- Why is mozzarella cheese so stretchy?
- If you are allergic to penicillin, can you eat Stilton?
Farming for microbes is next-level dairy farming. It requires a holistic approach that maximizes the diversity and health of the entire system. Rather than trying to wipe out any microbes that might be present, the farmer works to optimise the entire environment to encourage the beneficial ones. This touches all parts of the farming system, from the animals’ housing and feed, to the skin of the teats and even the milking machine. It involves just as much cleaning, but is a way of working smarter.
Though it may seem counterintuitive, making cheese in this way can increase the level of safety. Competition between microbes is an important phenomenon that keeps invaders out of healthy microbial communities. If beneficial and undesirable microbes are stripped away indiscriminately, there will be many fewer of the “good guys” occupying that space to compete with unwanted interlopers. Studies have shown that in environments where native microbial communities have been removed, spoilage microbes and pathogens can multiply to much higher numbers than they would if they faced competition.
Farming for, rather than against, microbes has benefits beyond the quality of milk for cheese. It also promotes animal welfare: animals must be given more space and their bedding must be refreshed more often to keep them clean enough to forego the strong chemicals. A calm, low-stress environment and immaculately tended feedstuffs are important too. And as we learn more about their potential unintended effects, and the ability of microbes to develop resistance, decreasing the use of antimicrobial compounds in the environment - particularly those that come into contact with food - is looking increasingly prudent.
Farming for microbes is an approach that we can believe in for its benefits to the environment and the sustainability of small businesses. But most importantly, by providing a route to make cheeses with unique flavours, it is one that we as consumers can also taste. The cheeses below are the products of farmers working at the forefront of this new movement, making the most of their own natural resources to create artisan cheeses that truly capture a taste of place.
Comté is one of France’s most popular cheeses, with a long history of production in the mountains of the Jura. Its success as an institution—over 40,000 tonnes of the cheese are made every year—has enabled its producers to be proactive. They collaborate with scientists to help them maximise the milk’s unique microbial potential and the cheese’s flavour.
The Comté producers have commissioned research encompassing everything from the impact of using native starters on the flavour of the cheese to the effects of different methods for milking on the microbial balance of the milk, then put the findings into practice with the help of professional training schemes and canny technologists.
Cardo and Old Ford
Mary Holbrook of Sleight Farm in Somerset makes these two raw-milk goat’s cheeses using only the microbes from her own farm and no commercial cultures. While Sleight Farm is not certified organic, no nitrogen fertilizers have been applied to its fields for decades, resulting in high biodiversity at every level, from the soil to the pastures to the raw milk that is used to make the cheese.
Holbrook was the first UK-based cheese farmer to monitor the health and vitality of her goats’ raw milk by allowing daily samples to sour at ambient temperature and assessing their taste and smell as well as the speed with which they acidify. Old Ford is a hard and savoury cheese with a natural, mould-flecked rind. In contrast, Cardo’s texture is more giving, and the naturally-occurring orange bacteria that grow on its surface give it a potent aroma.
Remeker is a gouda, but not as you know it. At De Groote Voort, their biodynamic farm an hour’s drive southeast of Amsterdam, owners Jan Dirk and Irene van de Voort farm a herd of 90 Jersey cows that have been bred specifically to thrive in a low-input, grass-based system.
For the van de Voorts, farming is first and foremost about soil microbiology and soil management, and their cheese is evolving to showcase the unique nature of the milk that they produce. Rather than being sealed in wax or plastic, as with most Goudas, the surface of their cheese, Remeker, is rubbed with bright yellow clarified butter, itself a byproduct of the cheesemaking process. This natural rind supports a complex surface microbial community that further contributes to the cheese’s flavour.
“Champsecret” Camembert de Normandie
Patrick Mercier is a third-generation dairy farmer in lower Normandy. He and his wife Francine farm an organic herd of 90 brown-and-white-spotted Normande cows. After selling the milk to nearby Camembert factories for many years, in 2012 they brought production of cheese back to the farm, making a classic Camembert de Normandie that fashions itself after the style of Camembert made in the 1950s. Today the Merciers are one of only two remaining farmhouse producers of Camembert de Normandie.
Patrick has taken great care to eliminate the use of chemicals in the milking parlour and to encourage the growth of native microbes in his milk through a long, slow overnight incubation before the cheese is made. He uses only a fraction of the normal dose of starter cultures in his cheese, and claims that he has made it successfully without any added cultures at all.
Holden Farm Dairy in Wales is the UK’s oldest organic dairy farm, and here herdsman Nick Millard and cheesemaker Rob Howard are working together to optimize the raw milk of the farm’s Ayrshire cows and turn it into a Cheddar cheese that a farmer a century ago would recognise. No chemicals are applied to the cows’ teats as part of the milking process; instead they are cleaned with fine wood shavings, a technique imported from continental Europe and popular with the makers of Alpine cheeses such as Comté, above.
Meanwhile, in the cheese room, Howard is ramping back the amount of commercial starter he uses, stretching the make out into a long and leisurely process that allows the milk’s native bacteria to grow steadily alongside the added cultures and play an increasingly-important role in flavour production.
The Calver family of Westcombe Dairy in Somerset is also on a mission to optimize the microbial diversity of its farms’ milk for their Cheddar cheese.
With the blessings of his father Richard, who manages the milk production side of the business, Tom Calver has embarked on a project to profile the microbial load of the milk and its changes over time, and to begin to build a picture that he hopes will associate the farm’s practices—from type of bedding, to the cows’ feed, to preparation of the teats for milking—with the identity of the microbes that predominate within the raw milk and the cheese.
Jasper Hill Farm
The Cellars at Jasper Hill | American Made Honoree⎢Martha Stewart (YouTube/Martha Stewart)
Meanwhile, in the US state of Vermont, brothers Mateo and Andy Kehler have invested in the technology and knowledge they need to give their raw-milk cheese production an extra microbial edge. Their cows are fed hay that has been dried using solar power to create a stable, nutritious feed that decreases the risk of pathogens in the milk sufficiently to produce soft, low-acid raw milk cheeses.
The Kehlers have also hired a full-time food microbiologist to isolate naturally occurring strains from their milk and farm environment that have the potential give their cheeses a more complex and nuanced flavour.
Reinventing the Wheel: Milk, Microbes and the Fight for Real Cheese by Bronwen Percival & Francis Percival is available now (£16.99, Bloomsbury)