When margarine goes “bad,” does it just lose quality or does it become unsafe?

It’s not likely to remain in your refrigerator long enough to become unsafe. Exposure to oxygen and bacteria cause margarine to go “off,” and the resulting rancid, “soapy” aroma and “paint-like” flavors usually deter consumers from consuming it long before it can become contaminated by dangerous bacteria.
 
Source(s):
Assistant Professor Franco Milani, Department of Food Science, University of Wisconsin