How about next to impossible? Take into consideration, as others have said - HIV dies really quickly once it hits the air.
Cooking would absolutely kill the virus. HIV does not survive above a temp of about 110 degrees.
Lastly, what kind of food is it? Salt (which is in almost everything,) salad dressings, citrus, tomato, sugar, etc. would all kill the virus on contact.
You may have heard the story about people putting HIV+ blood in ketchup bottles. That's a myth. Even if the virus didn't die in the air, the vinegar, sodium and acids in the ketchup would kill HIV right away.
The only way to be infected would be if the blood was absolutely fresh, and you had a cut in your mouth, the virus didn't degrade from the food or your saliva, & the virus miraculously found it's way in. Don't worry - food is safe!