Sun-dried tomatoes can be stored at room temperature if they are properly dried to a low moisture content and preserved in oil. Otherwise, they should be refrigerated or frozen.
Tomatoes, like other fruits and vegetables, contain a significant amount of water. Sun-drying removes this water, inhibiting the growth of bacteria, mold, and yeast that cause spoilage. For safe room-temperature storage, the tomatoes must be dried to a point where very little moisture remains. This typically involves drying them until they are leathery and pliable, but not sticky. Once dried, they are often packed in olive oil, which further protects them from spoilage by creating an anaerobic environment. The oil also adds flavor and helps to rehydrate the tomatoes slightly. If the tomatoes are not sufficiently dried or are not submerged in oil, they should be stored in the refrigerator or freezer to prevent spoilage and potential health risks. Properly dried and oil-packed sun-dried tomatoes can last for several months at room temperature.
To ensure your sun-dried tomatoes are safe for room-temperature storage, consider adding an acid like vinegar or lemon juice to the oil. This helps to further inhibit bacterial growth and extends the shelf life.