Eggs must be cooked to 160 degrees Fahrenheit to kill bacteria such as salmonella.
Adding alcohol inhibits bacterial growth, but it cannot be relied upon to kill bacteria.
The freshness of the eggs has no bearing on salmonella. You can catch the egg right out of the hen's bum and salmonella may still be present. Although an older egg may have more salmonella present as it will have had time to multiply.
Salmonella is especially risky for some people. This includes senior citizens, pregnant women and very young children. People with weakened immune systems who suffer from chronic illnesses such as cancer, diabetes, liver disease and AIDS are also at risk. So be particularly careful when serving eggnog to those individuals.
A good Eggnog recipe that uses cooked eggs, therefore eliminating any risk:
1 quart milk
6 fresh eggs
1⁄4 teaspoon salt
1⁄2 cup sugar
1 teaspoon vanilla
1 cup whipping cream, whipped
Ground nutmeg
Heat the milk in a large saucepan,
but do not scald. While heating, beat
together the eggs and salt in a large
bowl, gradually adding the sugar.
Gradually add hot milk to the egg
mixture.
Pour the mixture back into the
saucepan and cook on a medium-low
heat while stirring until it is thick
enough to coat a spoon. The thermometer
should read 160°F. If not, continue
heating until that temperature is
reached.
Stir in vanilla, and cool quickly by
setting the pan in a bowl of ice or cold
water and stirring for 10 minutes.
Cover and refrigerate until chilled.
Before serving, pour it into a bowl and
fold in whipped cream. Sprinkle with
nutmeg.