Curries actually evolved in India to extend the life of meat and chicken by masking off-flavors as the food was turning. Yogurt came about from milk processed in Mongol horsemen's saddlebags.
Other techniques evolved like pickling, creating pemmican and preserving dried meats and fish. Jam has always been popular, and Kilner jars are especially useful. Today, there are many practical aids for preserving foods.
When US settlers were heading west in earlier times, keeping milk and water fresh became of great importance. Today, preppers looking at extended periods in seclusion or travelling to another location face the same problem – a need for fresh and wholesome milk and no fridge, or a fridge and no power.