The Joys of Natural Microflora
21 Sep 09
Described by moderator Piero Sardo as “the pivotal workshop of Cheese,” the discussion “Cheese and Place: The Return of Microflora” held today at 12 pm, dealt with the use of natural bacteria to turn milk into cheese as opposed to the freeze-dried, packaged cultures commonly used in industrial (and increasingly artisanal) cheesemaking.
The president of the Slow Food Foundation for Biodiversity, Sardo opened the Milk Workshop by describing the problems facing producers who find it much easier to buy ready-made cultures than to use the microflora that occur naturally in the milk and the environment. For example, he said, almost all the cheesemakers in the mountain pastures of Béarn in the Pyrenees are using packaged cultures because they say their milk is now too clean and won’t start fermenting on its own. Even so, said Sardo, “we have to understand how to be respectful to nature and follow natural processes.”
Milan-based microbiologist Roberta Lodi of CNR-ISPA (Institute of Food Production Sciences) described microflora as the true agents of cheese production. “Cheesemakers believe they’re making cheese, but actually they are just taming bacteria,” she said. Outlining the microbiology of cheese production, she said that the biodiversity of indigenous microflora gives cheese its sensory characteristics, and that this biodiversity, currently at risk, needs to be protected.
The audience heard from three Presidia that use indigenous microflora. Judith Deflorin, coordinator for Swiss Presidia, described the complicated process used to make raw-milk butter in a small dairy in Wernetshausen, near Zürich. Biodynamic milk spends 30 hours in an incubator until its cultures become very active, then a spoonful is added to fresh milk. This process is repeated four times, then a liter of the culture is used to acidify cream, which is churned into butter. The whole procedure takes almost a week and requires great skill.
Dessislava Dimitrova of Slow Food Bulgaria then presented the Tcherni Vit Green Cheese Presidium. Families in the village of Tcherni Vit make a white sheep’s milk cheese which is brined in wooden barrels. When the barrels are opened, the cheese sometimes spontaneously forms a greenish-blue mold.
Presidium Aged Asiago producer Riccardo Rela from Veneto highlighted the practical difficulties of using natural starter cultures: “In recent years we can’t use them because the milk from my farm has fallen below the 10,000 bacteria count.” Now he is using industrial packaged cultures, which “save you from every problem,” but he would like to return to using natural microflora.
Professor Klaus Gutser of the Technical University of Munich offered a comparison between traditional dairying, modern raw-milk cheesemaking and industrial cheesemaking, showing how the temperatures and processes used in traditional dairying help keep many more bacteria alive. He suggested that the current legal limit for the bacteria count in raw milk is too low, and said that replacing wood with metal and the use of harsh chemical cleaning products in dairies made it hard for naturally occurring bacteria to survive.
As an alternative to packaged starters, cheesemakers can use self-produced whey or milk starter cultures. Giampaolo Gaiarin of the Trentingrana Consortium said that using these natural starters requires more time and effort and a better understanding of local conditions but resulted in a unique product. “With industrial starters cheese made in the mountains will be only slightly different from cheese made in the plains,” he said.
The last word came from Piero Sardo: “With the industrial packets the music is already written and the cheesemaker just plays it.”