Which Italian cheeses are made with raw milk, and why almost all of them are PDO

Raw milk means one thing only: it has not been taken to a temperature that kills microorganisms. The two treatments that rule it out are pasteurisation, most commonly 72 °C for around fifteen seconds, and thermisation, a gentler treatment around 60 to 65 °C.

What survives in raw milk is not only what people worry about. It is also the local lactic flora, which shifts with the pasture, the season, the barn, even between the morning and the evening milking. That population starts the fermentation and gives the cheese an aromatic profile that pasteurised milk, restarted from zero with selected cultures, cannot reproduce.

Put differently: raw milk carries geographical information into the vat. That is precisely why specifications call for it.

We looked at what each cheese in the atlas declares in the description of how it is produced, rather than anywhere else on the page. The distinction matters: a page may mention pasteurisation while discussing a similar industrial product, without that applying to the cheese itself.

Nineteen of forty-three declare raw milk. Ten declare pasteurised or thermised milk. The remaining fourteen do not specify, and most of those are fresh cheeses or products without a designation, where the choice belongs to the individual dairy.

The striking figure is a different one: of the nineteen raw-milk cheeses, sixteen are PDO. That proportion is too high to be chance.

A production specification describes a historic product and fixes the method for obtaining it. When that product comes from a valley where milk was worked as soon as it was drawn, because there was no other way, the specification photographs that practice and makes it mandatory.

So raw milk, which in mass retail would be a complication, becomes a legal requirement for anyone wanting to use the name. Parmigiano Reggiano and Grana Padano both work raw milk, and they are the two best-selling Italian cheeses in the world. Fontina is made from a single milking, still warm. Bitto is produced up on the summer pasture, where the milk has no time to cool.

At the other end sit designations that permit or require treated milk: Gorgonzola PDO is made with pasteurised cow's milk, and the same holds for several pasta filata cheeses. This is not a hierarchy of quality. It is a description of how each product has always been made.

European hygiene rules for products of animal origin require cheeses made from raw milk to say so clearly. In practice the packaging carries the wording «raw milk», and at a served counter the same information has to be available.

It is a useful obligation in both directions: anyone looking for that kind of cheese can find it, and anyone who for whatever reason prefers to avoid it can do that too. If the wording is absent, the milk was treated.

We stop here, at facts about processing. Whether any individual person should eat a raw-milk cheese is not a question a food atlas can answer: guidance for people in particular circumstances is published by health authorities, and they are the reference.

Anyone hunting for Italian raw-milk cheese in the United States quickly discovers that a lot of it is simply not there. The reason is a federal rule that turns seventy-six this year.

Since 1950 the Food and Drug Administration has allowed the sale of raw-milk cheese only where it has been aged at least sixty days at a temperature above 35 °F, just under two degrees Celsius. The rule sits in title 21 of the Code of Federal Regulations, part 133. Importers whose cheese falls short end up on the import alert list and the shipment is refused.

The consequence is sharp and explains many gaps on American shelves. Long agings pass, which is why Parmigiano Reggiano, Grana Padano, Fontina and aged pecorini are easy to find. What stays out is young raw-milk cheese, the kind eaten in Italy within weeks.

Worth knowing: the sixty-day rule has been argued over inside the United States for years, and studies on various cheeses have shown that the threshold alone does not guarantee the elimination of every pathogen. It remains the rule in force, and it is what decides what reaches the shop.

You can taste the difference, and it is not about intensity but about complexity. A raw-milk cheese tends to have a profile that moves across the tasting and that varies between one wheel and the next from the same dairy, because the starting flora is never identical.

It is also why the same PDO can give you two different experiences six months apart: the pasture changes, the milk changes, the cheese changes. A product from pasteurised milk with selected cultures is by construction more consistent, and for some uses that consistency is a virtue.

One practical point to close on: raw-milk variability compounds with ageing. A thirty-month Parmigiano and a twelve-month one are not the same cheese grown older. They are two products with different structure and different aromatics.