🔵 Blue cheeses

Blue cheeses are cheeses whose paste is veined with blue-green Penicillium roqueforti mould. The best known are Roquefort, Gorgonzola, Stilton, Danablu and Cabrales. The Codex Alimentarius general standard for cheese, CXS 283-1978, groups them with cheeses ripened mainly by mould growing inside the cheese. ¹

In the EU many names are protected designations of origin (PDO) listed in the eAmbrosia register. Roquefort is made only from raw sheep's milk and matured in the natural caves of Mont Combalou at Roquefort-sur-Soulzon. Gorgonzola is a cow's milk cheese from Piedmont and Lombardy, sold as dolce (mild) or piccante (sharp). ²³⁴⁵

The method is similar for all blue cheeses. Penicillium roqueforti spores are added to the milk or curd, and the curd is usually not pressed, so that small gaps remain inside. The young cheeses are pierced with long needles: air enters through the channels and the mould spreads in veins. Ripening lasts from a few weeks to several months in cool, humid rooms of the dairy. Mould enzymes break down fat and protein, giving a sharp, salty, spicy flavour. ⁷¹⁰

Why it tastes this way. Penicillium roqueforti gives these cheeses their texture, blue-green spots and aroma. Its enzymes, proteases and lipases, break down protein and fat, and that creates the sharp flavour. The mould can also form secondary metabolites, which are studied separately; the review describes how they are made, not how much is in cheese. ⁷⁸

Why they differ so much. The same method gives different cheeses, because each name's rules fix its own milk and place. Bleu de Gex is made from raw milk and sold from day 21, Bleu d'Auvergne from day 28 and Bleu des Causses from day 70, after ripening in caves with natural fissures. That cheese grew out of a law: in 1925 Roquefort banned cheese other than from sheep's milk, and a cow's milk blue developed around it. ¹¹¹²¹³

How to choose and serve. Look first for the name and PDO mark, because each protected cheese has its own rules: Roquefort is sheep's milk and matures in caves, while Gorgonzola is cow's milk. Taste depends on the type too: Gorgonzola comes mild (dolce) or sharp (piccante). Bleu d'Auvergne's makers suggest sweet white wines and amber beer, and that cheese also goes into a sauce for steak. ²³⁹¹⁰

Why this matters to you: the blue mould in these cheeses is not spoilage but part of the recipe, and knowing this helps you choose well and avoid throwing good cheese away. At the same time, the NHS advises pregnant women to avoid soft blue cheeses unless they are cooked until steaming hot. ⁶