Dear Advice Guy,
If frying oil is still good, and fryers are securely covered up for a couple of months, can the oil then be reused when we reopen?
– Linda, Manager, AICP, Philadelphia, PA
It is important to remember that frying oil is a food, not just a cooking medium, so the same food safety practices you use for any food should apply to your frying oil as well. Most fryers can only be loosely covered and storing them for long periods with oil inside is not a preferred practice.
Some operations such as seasonal restaurants or off-premise caterers may not use equipment like a fryer for a long period. In those cases, the oil should be discarded or, if reusable according to a test kit, filtered and stored in an airtight food-safe container in a cool, dry place, away from direct sunlight. The fryer should be thoroughly drained and cleaned and stored empty.
When reopening, test the oil again to see if it is still usable. If it is rancid from the long storage period, discard. Clean the fryer again and let it dry completely before filling.
More on managing deep fryers here.