about two hoursQuestion: How long can a sandwich sit out before it becomes unsafe to eat? Answer: Most types of sandwiches can be safely left out at room temperature for about two hours — or one hour if the temperature is above 90 degrees Fahrenheit.
6 hours maximum, if the sandwich contains meat and/or mayonnaise, unless the lunchbox has the capacity to keep food cold. If your lunch is a peanut butter sandwich, a cookie, and an apple, then it will last much longer. Use good judgement regarding what your lunch contains.
How long do sandwiches keep in the refrigerator? You should probably eat sandwiches within 3 days. Of course, if it doesn't look or smell right, you should not eat it regardless of the number of days.
To stay safe, sandwiches, salads, and other meals with perishable ingredients shouldn't be left at room temperature for more than 2 hours—max. Even if your lunch just contains one ingredient that's questionable—like mayonnaise—the whole thing should go in the fridge, Crowe says.
TipsKeep refrigerated, wrap sandwiches tightly with aluminum foil or plastic wrap or place in plastic bag or airtight sandwich container.For best results when freezing, coat bread completely with a layer of butter or margarine before adding filling, this will help prevent soggy bread when thawed.
The perishable nature of mayonnaise is also why you should throw out mayo that's been left out unrefrigerated overnight. It could be totally fine—until you get food poisoning. And, in general, the FDA recommends tossing perishable foods, including mayo, that have been left out at room temperature for two or more hours.
However, the virus is shed continuously from them: into the droppings and urine they leave around the room, and into their saliva, which dries on anything they have chewed, such as nesting material. Out in the environment like this, the virus can live for several days.
When stored properly, buttercream frosting can last in the fridge for up to a month, and in the freezer for up to three months.