Kimchi and sauerkraut have been famous and beloved dishes in Korea and Germany for centuries, and fermented food is currently among the most popular dietary trends.

Fermentation is used to describe the numerous different processes performed by microorganisms. But, what exactly can turn something like cabbage into a delicious meal, just by pressing it into a sealed jar so that it is covered in its own juice?

“When we ferment food, microorganisms such as lactic acid bacteria turn the sugar in vegetables into lactic acid, acetic acid, carbon dioxide and so on. This makes the food sour, but it protects it against unwanted decay and pathogenic germs, which are unable to grow in food that is adequately sour,” explains Jan Vester, a researcher specializing in bacteria at Novozymes.

Sealing the glass container is an important element in the fermentation process.

“The food ferments when there is insufficient oxygen present, and most harmful organisms thrive when there is oxygen,” explains Jan Vester. “Sealing the glass results in acidification and lack of oxygen, both of which limit unwanted growth.”
Bacteria are the most abundant organisms on earth, and Jan Vester is looking for bacteria that can be used to produce enzymes or sustainable fertilizer.

“Microorganisms are found everywhere in nature. Fruits and vegetables are quite naturally covered in microflora, including lactic acid bacteria, which ferment the sugar in vegetables into lactic acid,” says Jan Vester.
“You cannot see the lactic acid bacteria with the naked eye, but I am happy they are there – also when I ferment my food.”