Your doing it wrong. Anyone eating feed lot corn cow burgers and burritos should expect 24 hours on the throne as the norm, not the outlier. There are a lot more issues with fast food then just the building and staff hygiene. The food itself is suspect and lacking in real nutrition.
Eating healthy means eating single source foods that are preferably made from local organically produced ingredients. When you look at a plate of food there should be little mystery about where the food on it came from and how it was made. So many people buy the lie that visual equivalence in food equals nutritional or sanitary equivalence, but they are not and the clearest evidence of this is the sad state of the heavily chemically fertilizer salted, herbicide, insecticide polluted soils they come from.
Real health begins with an active healthy soil food web in soils high in organic matter that is continually replenished, which is then used to raise healthy diverse plant life that can nutritiously feed you, the animals that you depend on for food, AND the larger food web of wildlife that keeps the pathogens and pests in check. In race to the bottom for the cheapest convenience food, you, the mono cropped and feed lot food you are eating, and the polluted soil it is created on are the losers. If you want true "Homeland Security", start by making healthy choices and seeking out responsibly made food.
"A nation that destroys its soils destroys itself." ~ Franklin D. Roosevelt