San Marzano tomatoes have quite the reputation. They're said to be sweeter, pulpier and less acidic than other canned plum tomatoes, which is why so many people seek them out for their sauces. Unfortunately, most "San Marzano" tomatoes you'll find in grocery stores are frauds.
Photo by Mike McCune.
According to Taste, an incredible 95 per cent of tomatoes labelled as "San Marzanos" in the US are fake. It would be safe to assume that a fair number of tomatoes in Australia are suspect as well. You see, the name doesn't just describe the type of tomato seed used, but the region it's grown in, which happens to be in volcanic soil near Mount Vesuvius.
If you really want true San Marzano tomatoes, look for the words "Pomodoro San Marzano dell'Agro Sarnese Nocerino" and know that San Marzanos are never sold chopped, diced or pureed. They will also be expensive, as one would expect fancy Italian volcano tomatoes to be.
The Fake Rolex of Canned Foods [Taste]