Migros sells various ready-made salads, which I actually think is great. The only problem is that these salads have a strange aftertaste (as do other retailers). It is slightly sour and leaves a strange feeling in the mouth. (I know similar effects from eating an uncooked quince, for example. There, the feeling comes from the fact that the surface of the quince contains elements that attack the proteins on the tongue. Hence an almost "furry" feeling on the tongue)
It is possible that this taste and feeling is caused by a preservative, as I have never noticed this with homemade salads.
In any case, it's a shame because it makes the salads almost inedible (at least for me and some of my friends).
Perhaps the recipe could be revised. I would also be interested to know whether this phenomenon is known and can be explained.

Kind regards