You can safely leave meat sauce sitting out for up to 2 hours.
After 2 hours the meat sauce can grow bacteria and spoil so if the meat sauce was left out longer than a few hours or overnight the meat sauce should be thrown out to prevent getting sick.
If not eating or serving the meat sauce within 2 hours it should be refrigerated to prevent spoilage.
All homemade sauces including spaghetti sauce etc should be kept refrigerated to prevent spoilage.
When meat sauce goes bad the meat sauce will start developing a bad odor, sour smell, bad taste or even have mold growth in it.
If the meat sauce has any of those things then it should be thrown out.
If cooked meat sauce develops an off odor, flavor or appearance, or if mold appears, it should be discarded.
Meat Sauce and spaghetti sauce when kept refrigerated typically lasts between 7 days to 10 days before it goes bad.
Spaghetti sauce that has been continuously refrigerated will generally keep for about 7 to 10 days.
For best quality, do not store spaghetti sauce in opened metal can - refrigerate in covered glass or plastic container after opening.
How to tell if Spaghetti Sauce is bad, rotten or spoiled?
Spaghetti Sauce will begin to darken from a bright red to a maroon color and will get thicker over time.
After the eat by date has passed, the spaghetti sauce will begin to form mold, even in the refrigerator.
Properly stored, homemade pasta sauce will last for 3 to 4 days in the refrigerator.
To further extend the shelf life of homemade pasta sauce, freeze it; freeze in covered airtight containers or heavy-duty freezer bags.