FOOD

Scientists may have discovered why Swiss cheese has holes in it: apparently, it’s all down to how dirty the buckets are when milk is collected. (BBC)

Learn more about food science and sanitation with our Food Education resources.

Teachers, scroll down for a quick list of key resources in our Teachers’ Toolkit.

Discussion Ideas

• Will the “eyes” of Swiss cheese keep away the three blind mice?
  • Possibly . . . The holes in Swiss cheese are called eyes. Cheese without holes is known as blind. Maybe the three blind mice had decent sight but specialized in blind cheese?

• What creates the eyes in Swiss cheese?
  • Dirt! Microscopic particles of dust from hay settle into milk containers, and create holes by interacting with the milk, rennet, and bacteria used to make Swiss cheese. The more dust, the more holes.

• How did scientists conduct their experiment to discover how Swiss cheese gets its eyes?
  • According to the BBC, “Scientists reached their conclusions after adding small amounts of hay dust to milk and making it into cheese over 130 days.”
    • More specifically, the scientists used “a new method based on computed tomography—more commonly known as a CT scan—to study where and how holes formed.”

• Why have there been fewer holes in Swiss cheese in recent years?
  • Modern, high-tech milking methods are generally more sanitary. “Today, milk is no longer exposed to the elements before being turned into cheese because it is directly filtered through modern milking machines into large tanks.” (This is generally a good thing!)

• Will this new study—not yet peer reviewed!—help cheesemakers reverse the trend and develop more holey Swiss cheese?
  • Yes. Researchers “recommend that cheese producers who want holes to appear in their product add hay particles during the cheese making process.”

• Why does it matter if there are fewer holes in Swiss cheese?
  • The eyes are what makes Swiss cheese . . . Swiss cheese. Read through the USDA’s 14 pages of rules and regulations for Swiss cheese if you don’t believe me.
    • There are actually three grades of Swiss cheese: A, B, and C. For grade A cheese, “the majority of the eyes shall be 3/8 to 13/16 inch in diameter.” For grade C cheese, “The cheese may possess the following eye characteristics to a slight degree: afterset, cabbage, collapsed, irregular, large eyed, and small eyed, and the following to a definite degree: dead eyes, dull, frog mouth, nesty, one sided, overset, rough, shell, underset, and uneven. The cheese may possess the following texture characteristics to a slight degree: gassy, splits and sweet holes; and the following to a definite degree: checks, picks and streuble.”
      • OK, here’s a cheesy vocabulary list that will help you understand that paragraph and put you on your way to being a Certified Cheese Professional. You’re welcome:
        • afterset: “small eyes caused by secondary fermentation”
        • cabbage: “eyes so numerous within the major part of the cheese that they crowd each other, leaving only a paper-thin layer of cheese between the eyes”
        • collapsed: “eyes which have not formed properly and do not appear round or slightly
          oval but rather flattened and appear to have collapsed”
        • dead eyes: “eyes that have completely lost their glossy or velvety appearance”
        • frog mouth: “eyes which have developed into a lenticular or spindle-shaped opening”
        • nesty: “overabundance of small eyes in a localized area”
        • one-sided: “reasonably developed on one side and underdeveloped on the other as to eye development”
        • overset: “excessive number of eyes”
        • shell: “rough nut-shell appearance on the wall surface of the eyes”
        • underset: “too few eyes”
        • split: “sizable crack found within the body of the cheese”
        • sweet holes: “spherical gas holes, glossy in appearance; usually about the size of BB shot”
        • checks: “small, short cracks within the body of the cheese”
        • picks: “small irregular or ragged openings within the body of the cheese”
        • streuble: “an overabundance of small eyes located just under the surface of the cheese.”

TEACHERS’ TOOLKIT

BBC: Swiss cheese hole mystery solved: It’s all down to dirt

Nat Geo: Food Education

(extra credit!) USDA: United States Standards for Grades of Swiss Cheese, Emmentaler Cheese

American Cheese Society: Certified Cheese Professional Exam and the Body of Knowledge outline