While eating tomatoes for breakfast, lunch, and dinner is the best boon of August, leftover sliced tomatoes leave quite the conundrum: Do you stash the cut tomato in the fridge, as you would other fruit, and risk ruining its texture? The answer is somewhat surprising.
Fridge Storage Is Best
Yep, contrary to what we've been told about storing tomatoes in the fridge (it supposedly kills flavor compounds and makes tomatoes mealy), it is best to store cut tomatoes in the fridge. Cut tomatoes are magnets for bacteria and susceptible to spoilage outside the fridge — especially since most home kitchens are warmer in the summer months.
The optimal storage temperature for whole tomatoes is 55°F. While unripe tomatoes should always be stored at room temperature, recent studies suggest that it is actually fine (maybe even better) to store whole ripe tomatoes in the fridge, as long as they are brought back up to room temperature before eating. Assuming that you're slicing into a perfectly ripe tomato, stashing the other cut half in the fridge isn't going to ruin the tomato.
Store large tomato halves cut-side down on a paper towel inside a storage container and use within two days. The tomato will taste best if you can remove it from the fridge even 30 minutes before eating to bring it back to room temperature. Diced tomatoes should also be stored in a storage container in the fridge. After a few days in the fridge, cut tomatoes should be used or frozen.