Smelly Washing from my mechanism!? My Zanussi machine is not exactly up to date but works perfectly....

My Zanussi machine is not exactly up to date but works perfectly. However a few years ago wash started to come out smelling vaguely close to - to be frank - vomit! Then it stopped happening. But for the ending year it's been occurring again. It doesn't seem to concern what powder/liquid I use, if I use conditioner or not, take the wash out as soon as it's done, dry it indoors or out! I cannot understand why this should begin. I clean the drawer etc regularly. It's driving me insane. Has anyone else have this problem? I really need an answer on this one guys!
I cleaned near bleach immediately own a problem?
Answers:    Add a cup of white vinegar contained by the final rinse.P:)