Always a good topic, huh?
In the Scientific American article linked above, author Steve Mirsky talks about how a decades-old Swiss genetic experiment on flies is related to a more current set of experiments regarding what causes the formation and development of the eyes (or holes) in Emmental (or Swiss) cheese.
In the fly experiment, geneticists managed to get a fly to grow a ton of eyes all over its body by isolating and manipulating a few of the fly’s genes. More recently, 13 researchers at three different Swiss research facilities have figured out the link between the genetic fiddling needed to create the extra fly eyes and the genetic fiddling needed to regulate the size and quantity of holes in Swiss cheese.
The study, published as “Mechanism and Control of the Eye Formation in Cheese,” was published in the International Dairy Journal and contains a discussion on why eye/hole regulation is important.
“The size of the eyes of first-quality cheese should be between the size of a cherry … and a walnut,” says the journal article. However, different cheese-lovers prefer different sizes (and quantities) of eyes. “Italian consumers prefer Emmental cheese with walnut-sized eyes, whereas commercial manufacturers of sliced cheeses ask for cheese with smaller eyes and higher eye numbers.”
In making cheese, bacteria is key. A product of the bacteria is carbon dioxide, which forces the holes to expand to any given size, but until this study, it was unknown what made the holes themselves begin to form in the first place. Turns out, the process is analogous to the process of how a raindrop forms around a particle (a “cloud condensation nuclei”) in the vapor-saturated air. For the cheese, a little particle can act as an eye nucleus, around which the round hole begins to form.
In the study, the researchers chose hay dust as their particles of choice and found, through varying the amount of dust the young Swiss cheese was exposed to, that they could actually control the number and size of the eyes.
So they can basically do cloud seeding, but with cheese. Cheese seeding? Cheeding?
Anyway. Pretty cool!