|MadSci Network: Microbiology|
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.
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