When were ice creams invented?

Water ices were known in the Roman Empire and Marco Polo(1254-1324)  is said to have brought back a recipe for milk ices from his travels in the Far East.

Centuries later,  chefs for the royal courts of Europe were experimenting with ice cream and trying,  without success,  to keep the recipes secret.  In the 19th Century the commercial production of ice cream was made possible by the discovery that ice mixed with salt produced a lower temperature than ice alone.  The industry grew rapidly towards the end of the century because of the introduction of mechanical refrigeration.

About 80 per cent of the liquid mixture for making ice cream is milk and cream,  and about 15 percent is sweetener.  Sometimes egg yolk is used,  and fruit,  nuts and flavourings are often added to the mixture. 

Most commercial ice cream is made in a refrigerated tube with revolving blades or beaters.  The partially frozen ice cream is drawn off into containers and sent to a hardening room with a temperature of from-18° to-26°C. (0° to-15°F).  It is then delivered in refrigerated trucks to dealers. strict standards of hygiene have to be maintained.