You’ve probably swatted away a fly from your food, but have you ever wondered what it actually does when it lands on your meal? Spoiler alert: It’s pretty disgusting. Flies don’t just sit there—they vomit, slurp, and leave behind bacteria. Here’s how it all happens.
1. Flies Can’t Chew—So They Vomit Instead
Unlike humans, flies don’t have teeth or chewing mouthparts. Instead, they rely on a gross digestive trick:
✅ When a fly lands on your food, it spits out digestive enzymes from its mouth (a process called “extraoral digestion”).
✅ These enzymes break down solid food into a liquid form.
✅ The fly slurps up the pre-digested mush using its sponge-like mouth.
So, if a fly lands on your sandwich, it might be puking on it first before sucking it back up. Yikes.
2. Flies Carry Tons of Bacteria and Germs
Houseflies are walking (or flying) germ factories because they land on:
🗑 Rotting garbage
💩 Animal feces
🐀 Dead animals
They pick up bacteria, viruses, and even parasites on their legs and bodies. When they land on your food, they transfer all those germs instantly.
🔬 Studies show that flies can carry over 100 different pathogens, including E. coli, Salmonella, and cholera.
3. Flies Poop Constantly—Even on Your Food
Flies have a fast metabolism, meaning they need to relieve themselves often. And since they don’t have any bathroom etiquette…
🚫 They poop wherever they land—including on your food.
If a fly sits on your meal for more than a few seconds, there’s a good chance it’s left behind some tiny fly droppings.
4. Flies Also Lay Eggs on Food
If a fly spends too much time on your food, you may have another problem—maggots. Female flies can lay eggs in just a few seconds, and those eggs can hatch into tiny larvae within hours. While this is more common with exposed meat or rotting food, it’s something to keep in mind.
5. Should You Still Eat Food That a Fly Landed On?
Most of the time, a fly landing for a second or two won’t make your food unsafe—your stomach acid can kill some bacteria. However:
🚨 If multiple flies have been on your food, or if it was left out for a while, it’s safer to toss it—especially for things like raw meat, dairy, or wet foods.
🍎 If a fly lands on dry food (like a cracker), you can brush it off and likely be fine.
6. How to Keep Flies Away from Your Food
🦟 Cover your food when eating outside.
🦟 Keep your kitchen clean to avoid attracting flies.
🦟 Use fly traps or screens to keep them away from your home.
🦟 Take out the trash regularly—flies love rotting food.
Flies may seem like harmless pests, but their eating habits make them walking health hazards. The fact that they vomit, slurp, poop, and even lay eggs on food in a matter of seconds should make anyone think twice before ignoring them. While one brief landing might not ruin your meal, repeated exposure to flies can introduce harmful bacteria that cause foodborne illnesses.
If you frequently eat outdoors, keeping flies away is crucial. Use food covers, clean up spills quickly, and avoid leaving food exposed for too long. Indoors, maintaining a clean kitchen and taking out the trash regularly will reduce their presence.
Next time a fly lands on your food, you’ll know exactly what it’s doing—and you might not feel so hungry anymore!
