The plum tomato is an egg- or plum-shaped variety of tomato, bred for processing rather than fresh eating, and the standard choice for canning worldwide. Varieties like San Marzano and Roma share the defining traits: meaty flesh, few seeds, low water content, and skin that slips off easily after blanching, all of which give canned tomatoes their rich, dense character. Grown on a vast scale in Italy, California, and China, plum tomatoes are harvested at peak ripeness and processed within hours, which is why good canned tomatoes often taste better than fresh out-of-season ones. Nutritionally, canning increases the bioavailability of lycopene, the red carotenoid linked to prostate and cardiovascular health. The whole peeled plum tomato in juice remains the benchmark product against which chopped and passata formats are judged.