system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why do hamburger buns sometimes get moldy within days and other times last for a month or more even in the same environment?
gpt
Sometimes they've been on the shelf at the grocery store longer than others before you purchased them. Sometimes maybe the package wasn't closed properly, or the humidity changed. There are a lot of factors at play when it comes to food spoilage.