Mix all ingredients, and place in large saucepan. Heat to 160 °F while stirring constantly to prevent the eggs from clumping together and to provide a uniform temperature throughout. After cooking the mixture, refrigerate at once in shallow containers to allow egg nog to cool quickly.
To make your eggnog safe at home, use whole, liquid pasteurized eggs or liquid egg substitute (Egg Replacer will not work). Using either product would mean no further cooking is needed.
If you choose to use shelled raw eggs, you will need to cook the egg mixture to 160 °F.