You can keep it in there for a good few months. Pouring a little bit of olive or vegetable oil on the top will help keep it longer as it creates a protective barrier.
If the pesto sauce is home cooked with natural added preservatives such as salt and sugar , it will stay fresh for 48 hours in the refregerators. If the sauce has complex commercial preservatives...
Because of certain ingredients in this food, it will last for several weeks. Keep this food tightly capped. This will prevent other food odors from ending up in its flavor.
This food will keep for about 15 days in the refrigerator. Place the food in an air tight container for the best results. This food can easily be transferred to the freezer for longer storage time.