system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How are pre-cooked, non-frozen, TV dinners stay unspoiled without refridgeration or preservatives?
gpt
They're cooked and packed in a clean environment. Then they are sealed in a pack that does two things: 

Protect them from any bacteria getting in to spoil the food.  

Prevent air from entering so any bacteria not killed by the cooking can't grow and spoil the food.