Question

Tears have a high salt content that essentially desiccates or "dries up" microorganisms. Can you explain how this happens?

Answer 1

Sugar and salt both being hypertonic solutions, result in loss of water from the bacterial cell, thereby killing them. The increased concentration of salt in tears cause plasmolysis ( Contaction of cytoplasm from the cell well, caused due to the withdrawal of water from the cell when placed in a hypertonic solution).Hence, sugar and salt are also used as preservatives as they inhibit the growth of food borne pathogens.