Yes this is true, if you put canned food in the fire they start quickly destroyed, and must be heated and to keep warm. As the meat without pans and tripod spoils in the fire instantly.

Hello and thank you for the report JustCaused.
Currently this state is as designed, however we have passed this suggestion to our designers and they will decide wether the feature will be implemented or not.
Regards,
Geez

@Salem There are some cans that actually are designed to be put on fire. For example, cans used for camping or millitary meals, are often put on fire to get warmed up. Of course, some civilan/classic/less valuable cans get damaged if put on fire, but they dont get runied as in game. Usually ticket ( Paper that contains name of product, date etc. ) on cans get damaged, cans get a bit burned and have black color. But they never get ruined, so if you put can in fire, you can still eat food. All I want is to have red color that indicates warm object like after using heatpack, etc.

Hello JustCaused.
The option to heat up cans has been implemented internally and should be implemented on Steam soon. However keeping the cans on fire for too long will ruin them still.
Regards,
Geez