Why is vinegar used in food preservation?

Vinegar is an extremely acidic liquid. Very few microorganisms (ie bacteria and fungus which cause foods to spoil) can survive in such an acidic environment. Among other effects, it can destroy their cell walls, and prevent their own enzymes working (enzymes are extremely pH sensitive). There are a small number of microorgamisms which are adapted to survive in extreme acidity. However, this adaptation prevents them from surviving in more 'normal' environments. Therefore, anything which can survive in the vinegar, will not likely survive on your kitchen surface, and the same is true the other way around. Therefore, as vitually nothing can colonise whatever is in the vinegar, the food will be very effectively preserved. . . . . . . . . . . you can say . . the low pH a nd high acidity of vinegar destroy bacteria