If I leave some ground beef in my fridge for more than a day or two, it becomes visibly different, it browns, and just looks less appealing. I've been told that for ground meats it is especially important to cook them all the way through because even the insides have been exposed to bacteria in contrast to say a steak.
When I apply the same logic to sausages, it seems pretty bad. They are also made from ground meats, but because of the casing it is much more difficult to see if the meat inside is going bad. It seems to me that people keep sausages in their fridge for far longer than they would keep ground beef or other ground meats. For instance, sometimes my roommate has sausages in the fridge for 2 weeks or so, and I really wonder if that is okay or not.
My question is: Is this style of food preparation (packing meat into sausages) causing us to breed bacteria in our food and allow it to become more rancid than it would otherwise. Or is there something about the process that helps to preserve the meat similar to prosciutto or jerky?