Why do home made ice-cream recipes state the mixture needs to be heated before putting into an ice cream maker?

ice cream recipe book for ice cream maker image

Lynd-zeee

I've recently bought an ice cream maker, and i've noticed most of the recipes (in various different books and places online) it says to heat all the ingredients before cooling and putting into the ice cream maker.

Why does the mixture need to be heated? Will the recipe not work if I just put all the ingredients in a bowl cold and mixed together?

Thanks!

Answer
It's called pasteurization. To kill any possible harmful bacteria.