What early method lowered the melting point of ice for preservation?

Addition of salt to ice

Early rudimentary temperature control methods, long preceding modern refrigeration units, relied heavily on natural elements. To enhance preservation capabilities beyond simply packing goods with winter-harvested ice or snow, an important chemical modification was introduced. The process involved adding salt to the ice. This addition served a critical thermodynamic purpose: it lowered the melting point of the ice mixture significantly. The resulting colder mixture, essentially an early form of brine cooling, was far more effective at maintaining a preserved state for perishable items like fish or meat while they were transported across distances toward urban centers, establishing the fundamental principle that transit time requires thermal regulation.