According to the article linked in another comment, it’s this;

When the boar is in heat (thought they were always in heat) the meat ends up having a smell of ridiculously gross armpits and shit.

It’s only noticeable when the meat is warm, meaning you could get away with selling it refrigerated - until someone cooks it.

The worry is that people will simply stop buying pig flesh if enough of it is “tainted”, and so you need a worker that smell controls the flesh to ensure that the it can be sold.