I may be wrong, but I thought tomatoes were a New World product, like potatoes, maize and popcorn.
If this is true, then it's unlikely the ancient Romans would have had tomatoes to cook in their lead/pewter utensils. They may have cooked other acidic foods in lead pots, however. And it's true that tomatoes were considered poisonous in many areas until the last century.
You are right, nobody ate tomatoes in Europe until the 16th century. According to the California tomato growers site, it was northern Europeans who thought that the tomatoe was poisonous until the 19th century. It may interest you to know that that site says: 'This same fear persisted among colonists in the United States until the early 19th century; but in 1812, the Creoles in New Orleans put their cooking on the map with their tomato-enhanced gumbos and jambalayas'. I guess this makes you the expert on this subject. Since this is off-topic I will refrain from further discussion of this subject here.