I had assumed that the preservative function of covering foods with NaCl or brine was due to osmosis killing the microorganisms on the food by dehydration. However, I am now wondering to what extent denaturing of bacterial protein through interaction with salt ions could be responsible for killing the microorganisms. And what evidence suggests a dominant role for one or the other mechanism. I hope someone can clarify this matter for me. Thanks in advance.
1 Answer
In addition to killing microorganisms, the salt may provide a better environment for some 'beneficial' organisms, and a less beneficial environment for other 'problem' organisms. For instance, in production of kimchi and sauerkraut, salt encourages lactofermentation to the detriment of more harmful bacteria and fungi.
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$\begingroup$ This is interesting, and implies that the relative importance of osmosis vs protein-binding when preserving food with salt depends on the type of microorganism targeted. But I still wonder about the importance of osmosis in food preservation, whether or not lactofermentation is involved. In the latter case, are harmful microorganisms killed by dehydration? $\endgroup$ Jan 9, 2019 at 16:36