Which term refers to a can with both ends bulging?

The term that refers to a can with both ends bulging is "sweller." In the context of food packaging and preservation, a sweller indicates that gases have built up inside the can, often due to spoilage and bacterial growth. This bulging can be a significant concern as it suggests the contents are compromised and could be unsafe for consumption. Recognizing such signs is crucial for food safety and health, particularly for those handling food products.

The other options do not apply in this context. A "springer" typically refers to something that has the ability to spring back or be flexible, often used in mechanical settings. A "flipper" is more associated with a cooking utensil or a type of marine mammal and doesn’t pertain to can structures. "Expired" indicates that something is past its usable date, but it does not describe the physical characteristics of a can. Understanding these terms and their significance helps in recognizing issues with food packaging and ensures proper safety measures are followed.