Some things really were better in the good old days. It's not just nostalgia but scientific fact, for example, that tomatoes used to taste a lot better. Somewhere over the course of the late 20th century, they lost their tomato flavor.

How tomatoes went from a sweet-savory summer treat to something watery and bland presents not just a chemical and genetic mystery, but an economic and cultural one. Call it a fruit (the botanically correct term), or a vegetable (the way it's regarded in American and European cooking), and either way, the tomato is a global favorite. When the flavor disappeared, why didn't consumers rebel, the way they do when soda-makers change their formulas and the new version disappoints?

The answer is emerging from the field and the lab. Last week, a group of biologists from the United States and China unveiled the results of a multi-year study retracing the former flavor of the popular salad staple. The scientists isolated not just the chemistry of the tomato's lost taste but the genetics — opening up the possibility of creating the perfect 21st-century tomato, one that combines the high yields of today with the taste of yesteryear.