A Journey into Denmark’s Dairy History

In a Frederiksberg basement in Denmark, two dusty bottles sat unnoticed for over a century. Last year, researchers from the University of Copenhagen rediscovered them, revealing a suspicious white powder inside. What they found was a glimpse into the nation’s dairy-making past, containing bacteria that date back to the 1890s, previously used in butter production.

“It was like uncovering a kind of microbiological treasure. The ability to extract genetic information from such old bacteria connected to Danish butter production was beyond our expectations,” remarked Jørgen Leisner, one of the authors of a recent study that detailed these findings.

Examining the labels on the bottles, Leisner and his colleagues identified cultures of lactic acid bacteria—microorganisms crucial for food preservation and flavor. They extracted DNA from the samples and compared it against established bacterial databases.

In their analysis, they found traces of the lactic acid bacteria Lactococcus cremoris, still commonly used by Danish dairies today to acidify milk and eliminate harmful bacteria after pasteurization.

Additionally, the researchers identified genes in L. cremoris related to dairy adaptation, including those responsible for buttery flavors. This is particularly intriguing considering that during the 19th century, a mild flavor was preferred in Danish butter for the English market.

By the end of the 1800s, Denmark was exporting butter to England in significant quantities. To maintain product quality, milk underwent pasteurization before bacterial cultures were introduced—these starter cultures played a pivotal role in imparting acidity, flavor, aroma, and texture, while also preserving the butter.

“The introduction of starter cultures revolutionized butter production, eliminating the individual fermentation methods of various dairies. This ensured a consistent taste across the board, regardless of where in Denmark the butter was produced,” Leisner explained.

However, the bottles also contained traces of less desirable bacteria. The presence of Cutibacterium acnes, known for causing acne, and other potentially harmful bacteria like Staphylococcus aureus and Vibrio furnissii highlighted the challenges faced by the dairy industry during that era.

“The contents of these bottles reflect a time when dairy products were often made at home by farming families but illustrate that hygiene standards have dramatically improved since then,” co-author Nathalia Brichet noted.

And if you’re curious about ancient dairy products, there’s talk of finding cheese over 3,000 years old, discovered on mummies. Perhaps it’s safer to stick to bread, like the astonishingly old loaf dated at about 8,600 years!

The study appears in the International Dairy Journal.