“Flies don’t have teeth,” according to an article from the University of Sydney. “They can’t take a bite out of our food, so they have to spit out some enzyme-rich saliva that dissolves the food, allowing them to suck up the resulting soup of regurgitated digestive fluids and partially dissolved food.

In most instances, spotting a fly on your food doesn’t mean you need to throw it out. While there is little doubt that flies can carry bacteria, viruses, and parasites from waste to our food, a single touchdown is unlikely to trigger a chain reaction leading to illness for the average healthy person.

Flies that land out of sight and wander about for a few minutes vomiting and pooping on your food or food preparation area are more of a concern. The more time passes, the greater the chance of pathogens left behind by the flies growing and multiplying on our food. That’s when health risks increase.”