Are canned tomatoes that dark on top good?

Canned tomatoes that have a dark color on top may be a sign of oxidation or spoilage, especially if there are signs of mold or an off smell. However, if the can is undamaged, and the contents smell and taste fine, they are likely safe to consume. Always check the expiration date and inspect for any other signs of spoilage. When in doubt, it's best to err on the side of caution and discard the can.