Q: Why is it safe to simply sear the outside of whole muscle cuts of meat, as opposed to cooking ground meats to higher temperatures?
A: Bacteria are usually concentrated on the outside surfaces of whole muscle cuts of meats such as steaks, roasts, chops. Cooking these foods to 145˚ F kills bacteria to safe levels. Because grinding meats essentially distributes bacteria throughout the product, it is necessary to cook these products to higher internal temperatures, 155˚ F for safe eating.
Q: If I wrap a food, like a leftover turkey sandwich, in air tight plastic wrap, can I keep that food out overnight on the counter?
A: It’s not the air that is the risk to foods being left out overnight, but warm air temperatures (between 41°F and 135° F) that can allow dangerous bacteria in these foods to grow. The protein (turkey) in your sandwich is potentially hazardous- your sandwich should be wrapped to protect it from outside bacteria, but also refrigerated to prevent excessive bacterial growth overnight.