Eli5 How can canned meats like fish and chicken last years at room temperature when regularly packaged meats only last a few weeks refrigerated unless frozen?

Question

Eli5 How can canned meats like fish and chicken last years at room temperature when regularly packaged meats only last a few weeks refrigerated unless frozen?

In: Chemistry

Answer 1

When food is canned it gets a “12D-kill” – which means it’s heated at a high enough temperature and pressure to kill all microorganisms, including *Clostridium botulinum*, the most dangerous food borne pathogen. So the food inside the sealed can is essentially sterile, and the food will remain unchanged for months if not years in the can. Eventually chemical processes may make the food unpalatable- but that’s a quality, not a safety issue.
When meat is refrigerated it significantly slows microorganism growth – but – spoilage bacteria will grow, slowly. These cause off odors, sliminess etc. Also a significant food borne bacteria *Listeria monocytogenes* can still grow at refrigeration temperatures.