You've eaten something with a neomorph spore in it, BUT, it passed...

...through your system without activating for some reason (You could have been ill, perhaps it detected the environment wasn't right, maybe you'd drank too much milk or something, something stopped it from doing its thing for whatever reason).

Anyway you flush your poop away and some fish then eats it. "Munchetty-crunchety!" it goes. Then a fisherman catches that fish and uses it to catch a bigger fish again "Mmm, Munchetty-crunchety!!" that one goes too! before getting torn from the ocean and placed up against other caught fish. That fish gets sold at a market and a restaurant buys it and serves it up to a customer who goes "Munchetty-crunchety!!!" before the spore then activates and takes them out with a Gutbuster.

If that Gutbuster grows into a full neomorph and then finds you and eats you will it say "Mmm, Munchetty-crunchety!!!!" or not? 

My bestestest funny evah!!! https://vid.me/ToVD