Tomatoes are used in a wide variety of recipes, and also make a nutritious snack between meals. As with other fruits and vegetables, a tomato is only good for a set amount of time. Once this time passes, eating the tomato or adding it to a recipe is not recommended. Thoroughly inspect the inside and outside of a tomato for signs it has gone bad to prevent you and others from getting sick.
Notice the color of the tomato. Throw it away if it is not a solid red color or if you see any discoloration.
Look for cracks, mold spots, sunken areas or other damage on the outside surface of the tomato. All of these indicate the tomato is bad.
Grip, don't squeeze, the tomato. A good tomato is firm enough that it doesn't sink in as you hold it. Throw the tomato away if it seems soft.
Smell the outside of the tomato. A bad tomato smells rancid and unpleasant.
Slice the tomato in half. Feel the inside of the tomato. Throw it away if its inside feels slimy.
Inspect the inside of tomato for mold spots, discolored areas or rancid smells. Discard the tomato if you notice any of these conditions.
Do not eat a tomato you think is bad, as rotten tomatoes cause food-borne illnesses. Use a “better safe than sorry” approach if you're unsure about the quality of the tomato.