I never heat fruit for wine, except for my banana wine recipe. Heat does a couple of things- it sets the pectin (think jelly) and it gives the wine a "cooked fruit" flavor. Sort of like the difference between a eating a fresh apple and eating the apples out of an apple pie.
Most winemakers use campden tablets (sulfite) to sanitize the fruit when they make up the must. One campden tablet per gallon of wine must (crushed and dissolved in some water) will do the trick and then just add the yeast 24 hours later.
I normally put the campden tablet(s) in 1/4 cup boiling water and pour that over my fruit and then continue by adding the water and sugar and the rest of the ingredients (except for the pectic enzyme and yeast). Stir well, let it sit for 12 hours and then add the pectic enzyme. 12 hours after that, add the yeast.