system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why is some canned food immersed in liquid?

E.g. canned tuna, canned sardines
I've seen some jarred chicken sausages immersed in brine too.
On the other hand, some canned food like spam do not have a bath. Why is that?
gpt
Canned food needs to be sterilized to keep bacteria and mold from spoiling the food.  To do this, the food is cooked in the can, *after* its sealed.  Foods which fill the entire can, like SPAM or refried beans, distribute the heat well.  Foods which would have air space wouldn't heat evenly without something to distribute the heat.