Holey Cheese!

Holey Cheese!

BY : Rhiannon Nevinczenko

Swiss cheese is famous for its holey-ness. But how on Earth did those holes get there?
Cheese is one of many foods that require fermentation to produce. Fermentation is an anaerobic process - basically, the desired microorganism (such as bacteria or yeast) is put in a situation where it has plenty of food, but no oxygen. This forces the microorganisms to undergo anaerobic cellular respiration (to use the available sugars despite the lack of oxygen).
For food products like Swiss cheese, safe bacteria that will produce the desired effect are used. In cheese-making, the lactose in milk provides the food for the bacteria. First, cheese-makers combine the milk and bacteria and heat them to produce curds. The curds are then given a brine (salt water) soak, which creates the protective cheese rind, locking the bacteria inside. The wheel of cheese is set in a location where the fermentation process can occur for a few months or years, until the product is finished and ready. Different bacteria are used in different cheeses. In Swiss cheese, P. shermani is used, which produces carbon dioxide as a byproduct of fermentation. As they produce carbon dioxide gas, bubbles form inside the cheese, trapped by Swiss' thick rind. These holes are called "eyes" in the cheese-making industry. The size of the cheese eyes can be controlled by manipulating variables such as temperature, acidity, and aging time. This is why, for instance, baby Swiss (which is aged for less time) has smaller holes and a milder flavor.
Image credit: NastyaSensei via Pexels. Pexels license.

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