Sardines are small oily fish that can be sold fresh or canned. While canned sardines have a long shelf life, they do eventually go bad and become unsafe to eat. The amount of time it takes for sardines to go bad depends on how you purchase and store them. To avoid health risks, learn how to properly store sardines and recognize when they are spoiled.

While fresh sardines will only last a few days in the refrigerator, canned sardines can last as long as five years if stored properly, according to the FDA. Canned sardines may still be safe to eat after five years, but the flavor and quality will likely degrade. Always discard a can of sardines if it is rusted, damaged or swollen. Even a dented can may have been exposed to air, which greatly reduces shelf life.

Just like most canned foods, canned sardines should be kept in a cool, dry place, preferably under 70 degrees Fahrenheit, according to Ohio State University. Avoid storing canned sardines above 95 F, as this can result in rupture or explosion. Failure to store canned sardines correctly can greatly reduce their shelf life.

If you decide to buy fresh sardines, you’ll need to consume them within a few days. Fresh sardines that have gone bad are easy to identify by their foul smell. The fish may also have sunken or dull eyes and collapsed bellies. According to the FDA, canned sardines that have been opened will last three or four days in the refrigerator. Sardines that are left in the can after opening may develop a metallic aftertaste, so place them in a covered glass or plastic bowl.

If you purchase fresh sardines, rinse them as soon as you get home. Place them in a plastic storage bag in a large bowl filled with ice and put the bowl in the refrigerator. This will keep the temperature down without freezing the fish. Drain the melted water and replenish ice as necessary. While this method will not increase the shelf life of sardines past two days, it will ensure that they are fresh when you consume them.