19. After how many hours should you toss food if it’s been sitting out?

2 hours

Explanation:

There is a 2 Hour Rule: toss any perishable food (the kind that can spoil or become contaminated by bacteria if left unrefrigerated) that has been left out at room temperature for more than two hours. When the environmental temperature is above 90° F (32° C), throw out the food after one hour.

2 hours

Explanation:

"The "2-hour rule" states that perishables left at room temperature for more than two hours should be discarded."

After two hours, then yes you should throw your food away according to what I have read.