The variations of blood sausages basically differ according to their shelf life. This results from the production process and the type of packaging. During production, the blood sausage is either filled into sausage casings, tins or jars. Finally, some varieties are smoked, which increases the shelf life.
So the most important thing for you is what quantity you buy and in what packaging. With fresh sausage, for example in ring form, you should be careful not to take too much at once. Otherwise your black pudding could go bad more quickly. However, if you buy several tins or jars, for example, you have a longer shelf life and don't have to use it all up right away. Once opened, you should of course treat the packaging like fresh produce and use it up quickly.