 Checkup on Health with Chris Whitting. Could you have rancid foods in your kitchen or pantry? Dr. Eric Decker, head of the Department of Food Science at the University of Massachusetts, has some advice that you can use. First thing I would do is look for your can of shortening, especially if you're keeping shortening at room temperature and not refrigeration. And then I would look at any vegetable oil. At least in my household, we refrigerate all our oils and all our shortening in refrigeration.