Is Cheese Even Vegetarian?

Most vegetarians eat cheese without a second thought. Most cheese, the traditional kind, is set with an enzyme from a slaughtered calf. So is cheese vegetarian or not? The answer is a genuinely funny mess, and it ends with two vegetarians standing at the same shelf reaching for opposite blocks, both completely right.

A vegetarian friend put parmesan on her pasta the other night, and I didn't have the heart to tell her.

Here's the thing she didn't know, and most people don't. Cheese is milk, which doesn't require killing anything. But cheese only becomes cheese because of rennet, the enzyme that sets the curd, and traditional rennet comes from the fourth stomach of a slaughtered milk-fed calf. So the most traditional cheeses, the famous ones, the ones you'd put on a board to impress someone, have a dead calf in them. Her pasta included.

Which raises a question that sounds stupid and isn't: is cheese even vegetarian?

To answer it you have to do something nobody usually bothers to do, which is define the word.

What "vegetarian" actually means

It isn't one thing. It's a family of positions with different lines drawn in different places.

A lacto-ovo vegetarian eats dairy and eggs but no meat, fish or poultry. This is what most people mean when they say "vegetarian." A lacto-vegetarian keeps the dairy, drops the eggs. An ovo-vegetarian does the reverse. A vegan drops all of it, dairy, eggs, the lot.

Notice what the common thread is, because it's the whole key. The standard vegetarian line isn't "use no animals." It's "kill no animals." That's why milk and eggs are fine, the cow and the hen are still alive, while meat isn't. The objection is to slaughter.

And the moment you see that, the cheese problem snaps into focus. Milk passes the test, nothing died. But calf rennet fails it, because a calf did. So a single block of cheese can be acceptable on the milk and unacceptable on the enzyme, by the vegetarian's own rule. The cheese isn't confusing. The definition is working exactly as designed, and it lands right on the rennet.

The fancy cheese is the problem

Now the part that genuinely surprises people, and it's backwards from what everyone assumes.

You'd think the expensive, authentic, traditional cheeses would be the "clean" ones and the cheap industrial blocks would be the suspect ones. It's the other way around.

Real Parmigiano-Reggiano is required by law to use calf rennet. It's a PDO cheese, Protected Designation of Origin, which means its recipe is written into EU regulation, and that recipe mandates animal rennet. A cheese made any other way literally cannot be sold as Parmigiano-Reggiano. So authentic parmesan is never vegetarian, and it can't be, by definition. The same goes for Grana Padano, Pecorino Romano, Gruyère, and Spanish Manchego. The grander and more protected the name, the more certainly there's a slaughtered calf behind it.

Meanwhile the cheap supermarket block, the mild pre-grated "Italian hard cheese" in the plastic tub, is far more likely to be set with the lab enzyme and stamped suitable for vegetarians. The budget option is the veggie one. The one with the heritage and the wax seal and the Italian consortium is the one your vegetarian friend should put down.

So when she sprinkled "parmesan" on her pasta, the answer to whether that was vegetarian depended entirely on whether it was the real thing. If it was a genuine wedge of Parmigiano-Reggiano: no, calf rennet, sorry. If it was the cheap stuff: probably yes. The better the cheese, the worse the news.

(One aside, since it comes up: the exact same rennet rule decides whether a cheese is halal. Animal rennet from a non-ritually-slaughtered calf makes traditional parmesan non-halal too. One little enzyme quietly governs two completely different diets at once.)

How to actually read the label

The good news is there's a single reliable test, and it takes one glance.

Look for "suitable for vegetarians." That mark is a guarantee of non-animal rennet, the lab or microbial kind, no calf. If it's there, you're fine.

If it isn't, read the rennet line:

• "Non-animal rennet," "vegetarian rennet," "microbial rennet" — no calf. Vegetarian.
• "Animal rennet" — calf. Not vegetarian.
• "Enzymes," or nothing at all — unknown, and on a traditional or imported European cheese, assume calf.
• A PDO or AOP stamp on an Italian or French hard cheese — assume calf, because the law probably requires it.

Rule of thumb for when there's no label to read at all, like a restaurant cheeseboard: old, hard, European, aged, expensive usually means animal rennet. Young, soft, supermarket, cheap is more likely to be vegetarian. It's almost the opposite of how people rank cheese by quality.

The paradox at the end of it

Here's where it gets properly funny, and it's the thing I can't get over.

Picture two vegetarians at the same supermarket shelf.

The first one became vegetarian to avoid killing animals. For her, the lab rennet is a gift. The genetically modified microbe that produces the enzyme is the entire reason she can eat cheese at all, because it set the curd without a calf. She reaches for the block marked suitable for vegetarians, the industrial, biotech one, and she's right to.

The second one is suspicious of genetic engineering and lab-made ingredients. She wants her food traditional, unprocessed, made the old way. For her, that same lab enzyme is the thing to avoid, and the calf rennet, the actual traditional method, is the "natural" choice. She reaches for the traditional block, the one with the calf in it, and by her own logic she's also right.

Same word. Same shelf. Opposite blocks. Both consistent.

And the punchline underneath it: the lab-grown, GM-microbe enzyme that the natural-food world is most suspicious of is the single thing that made cheese vegetarian in the first place. The most "industrial" ingredient on the shelf is the one quietly serving the most "natural" diet. For ten thousand years cheese was a slaughter product. The thing that changed that wasn't a return to nature. It was a fermentation tank.

So, is cheese vegetarian? Depends which cheese, depends which vegetarian, and the answer is held inside one tiny enzyme that the label usually doesn't bother to explain. Which is, when you think about it, the most cheese answer possible.

Related reading from OFT:

• What Is Non-Animal Rennet, and Is It in Your Cheese? — what the enzyme actually is, and which NZ cheeses use what
• Mainland Organic Cheese: Is Non-Animal Rennet Legit? — the one block where you can watch the whole thing play out