Re: Can you keep bacteria from growing in food by adding salt or vinegar?

Hi Cynthia,

Salt and vinegar are commonly used as food preservatives.  Salt works on 
the principle of osmotic pressure.  The salt ions in the food keep water 
from being available for microorganisms to use; so you can have a high 
moisture food, but the water is not available to most bacteria.  Vinegar 
works by reducing the pH of the food into the acidic range, because 
vinegar contains a lot of acetic acid which gives it its sour taste.  Most 
bacteria do not tolerate acidic conditions.  Pickles are a good example to 
look at. They have a lot of salt and vinegar added.  A pickle has a much 
longer shelf life than a raw cucumber.  Hope that answers your question.