Quote from r-in:
My understanding has been that store tomatoes at the big stores have been gentically altered so when they are in the store they are red and pretty, but this process sacrificed taste and flavor.
when i owned a trucking company we used to haul tomatoes out of california. they go on the truck green and depending on the length of the haul(usually 2000 miles)the trailer temp would be adjusted so they would just ripen in about the 36 hours it took to make the trip. they do turn red but they arent ripe. thats why they have no flavor.
