system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why are some meats safe to eat raw and some not?
gpt
all non contaminated meats are safe to eat raw.   problem is....some meats come from the animal already contaminated.   

if you had a healthy chicken that was disease and parasite free, you could eat the meat raw if you freshly slaughter it.    but you don't, because you buy your meat the supermarket, where it comes from a slaughterhouse and packing plant at least a week old.   and the chicken comes from a chicken farm where it's packed with other chickens that are contaminated with the bacteria salmonella.   

if you had a healthy pig that was disease and parasite free, you could eat the meat raw if you freshly slaughter it.    but you don't, because you buy your meat the supermarket, where it comes from a slaughterhouse and packing plant at least a week old.   and the pig comes from a pig farm where it's packed with other pigs that are contaminated with the parasite trichinosis. 

if you had a healthy cow that was disease and parasite free, you could eat the meat raw if you freshly slaughter it.    but you don't, because you buy your meat the supermarket, where it comes from a slaughterhouse and packing plant at least a week old.   but luckily, there isn't a widespread bacteria or parasite that affects cows.   their meat is pretty resistant to random bacteria getting into the inside of the meat.   you would be mostly ok to eat supermarket beef raw.   if you get fresh slaughtered beef, you would be even less risk.