At Room Temperature - If you are using parmesan cheese, this seasoning can only remain at room temperature for 2-3 days before losing quality. You could also mix everything except the parmesan cheese together and have it be shelf stable for a year! If you make a big batch to store, omit the parmesan cheese when you make the seasoning. Then add the parmesan cheese to the amount that you'll need each time you use it.
In the Refrigerator - Store in an airtight container for up to four months in the refrigerator.