Food Preservation and Storage

Food Preservation Storage

Lesson 11: Preservation by Use of Salt and Sugar

Principle of Preservation by Salt

Salt acts as preservative when its concentration is increased above 12 per cent. Salt levels of about 18 to 25 per cent in solution generally will prevent all growth of microorganisms in foods. However, this level is rarely tolerated in foods except in the case of certain briny condiments. Salt exerts its preservative action by plasmolysis of microbial cells due to high osmotic pressure, drawing moisture from microbes, ionizing to yield chloride ion, which is harmful to microorganisms, reducing the solubility of oxygen to water, sensitizing the cells against carbon dioxide and interfering with the action of proteolytic enzymes.