Because freezing does not kill harmful bacteria, when food thaws, harmful bacteria start to grow and multiply again.
The refrigerator is better suited for thawing. Four to five pounds of meat takes 24 hours to thaw. While food can be thawed outside the refrigerator by immersing it cold water, the water must remain cold to prevent bacterial growth and, consequently, the water should be running or must be replaced every half hour.
Foods may also be thawed in the microwave. Cooking should follow immediately to prevent bacteria from growing on the surface.