What Did People Use Before The Fridge Was Invented?

They would keep food, in box's to try and keep it cold

They would use salt to keep things fresh. And keep them in a box in a cool place.  probably tasted bloody horrible but

Ice boxes were used to keep food cold. Of course, the ice had to be refreshed more or less often, depending on the insulation in the box, the outside temperature, and how often the box was opened. I remember my mother telling a story of cutting blocks of ice from the farm pond in the winter time and packing them in straw in an underground storage area so ice would be available later in the year.

Food was preserved in other ways, too. It was canned, dried, salted, smoked, or preserved with peppers or herbs to inhibit mold or rot.