It is virtually impossible for food-borne illnesses to grow in the freezer at 0 F. Therefore, milkshakes will last indefinitely. However, over time, the quality of the milkshake will start to suffer as ice crystals might start to form. For best quality, consume the milkshake within 1 to 2 months after it's frozen.

It's important to properly store your milkshake in the freezer to preserve quality. First, store the milkshake in the main part of the freezer away from the door. This will keep the milkshake away from fluctuating temperatures when the door opens. Additionally, milkshakes are best stored in an airtight container. Try to find a sealable container that is slightly larger than the cup and place the whole thing inside before sealing. This will keep other frozen food flavors from contaminating the milkshake. A zip-top plastic bag or plastic wrap is another option when storing the milkshake.

The USDA recommends practicing cold thawing methods to avoid the growth of bacteria. Move the milkshake from the freezer to the fridge for about 30 minutes while still in the sealed container or bag. You'll be savoring the creamy, thick beverage in no time.