Jarred pizza sauce lasts about one to two weeks, once it's been opened and refrigerated. Homemade sauce usually has a shorter shelf life because it doesn't contain as many preservatives as jarred varieties. Both products are susceptible to growth of lactic acid bacteria, yeast and mold. The easiest way to tell if your sauce has gone bad is to observe it. If it smells, looks or tastes bad or "off," discard it immediately.
Handle With Care
The high acid and salt content of most pizza sauces makes it more resistant to mold and bacterial growth than some other foods. Still, if a dirty or used spoon entered the jar prior to refrigeration or if the sauce was left out of the refrigerator for an extended period of time, it may spoil sooner than in one to two weeks. Your refrigerator should also be at 40 degrees F or colder to slow down the growth of microbes. If you're not sure how the sauce was treated or whether your fridge is cold enough, it's safest to toss any leftover pizza sauce. If you've heated the sauce once and then refrigerated it, keep it just about three days.
Unopened jars of pizza sauce that are past their "sell-by" or "best-by" dates are probably okay to eat. These dates usually indicate freshness and best taste, not food safety. If you do open a jar of sauce that's past it's sell-by date and it looks or smells bad, toss it.