Chemists sniff out fake Parmesan cheese
Italian researchers found a way to spot the dodgy stuff. Belinda Smith reports.
It's not called the King of Cheese for nothing – but the delicious Parmigiano-Reggiano, or Parmesan cheese, isn't always what it seems.
Like any other luxury product, it's prone to forgery, with some alleged grated "Parmesans" made of cellulose and other, cheaper cheeses – and not a skerrick of the real stuff.
So how do you know if you're being ripped off?
In the Journal of Agricultural and Food Chemistry, Italian chemists led by Augusta Caligiani from the University of Parma published a way to detect fake Parmesan.
One of the requirements for cheese to carry the Parmigiano-Reggiano label is it must be made using milk from cows fed hay or grass – not silage, a fermented cereal product.
So Caligiani and colleagues decided to see if they could detect compounds in cheese produced by silage-fed cow milk. They ran 304 cheese samples through a mass spectrometer and gas chromatographer, analysed their chemical make-up and tried to nail down particular "signatures" of silage-fed cow milk.
The cheeses tested included Grana Padana and Fontina, also from Italy, French Comté and Swiss Gruyère, all of which are made from silage-fed cow milk.
They were successful. Grana Padana, another hard cheese similar to Parmesan, contained cyclopropane fatty acids. These fatty acids weren't present in true Parmesan samples.
They were even able to tell if a blend of the Parmesan and Grana Padana contained 10-20% Grana Padana. And because the process is quick and easy, industry-wide screening may soon become the norm, the researchers say.