What Happens When a Fly Lands on Your Food?

It's such a common scene that we barely pay attention to it: A fly approaches our food, lands on it, we try to shoo it away, it takes off and tries again. The fly is associated with dirt and bacteria, though few really know its mechanism of action. A surprising detail is that the fly doesn't bite or chew, but the real problem lies in its previous journey, because human food is just one of many things that attract it…

Even the cleanest place in the world can become an attraction for flies. I've personally seen them buzzing around compact fluorescent lights, but there's nothing a good insecticide can't solve. However, we're fighting a losing battle.

The presence of the common housefly (Musca domestica) is directly linked to humans due to its commensalism, and its distribution is global. So it's almost inevitable that from time to time a fly lands on a cut apple, the rim of a teacup, and other food sources. Open-air markets, butcher shops... they're everywhere, waiting for an opportunity.

Now the question is: What exactly happens when a fly lands on our food?

First of all, the fly has no teeth and cannot ingest solids directly. When it settles on the surface of food, the fly regurgitates saliva, turning it into a liquid that it absorbs with its proboscis.

In less scientific terms, what the fly does is vomit on the food and then consume it. If that image isn't bad enough, there's more. The fly acts as a mechanical vector for hundreds of pathogens, including those responsible for cholera, typhoid fever, tuberculosis, anthrax, and salmonellosis.

This is because it takes advantage of other food sources, like decaying matter and animal excrement. Those pathogens travel with the fly (which sometimes moves for kilometers), and they can be transferred to our food.

The only problem I have with the video is the dramatic touch at the end: Throw away the whole cookie? A more efficient solution would be to remove the section where the fly was. It's also not a big deal to have a fly on raw food if you're going to cook it at high temperature later, killing anything that might be on its surface during the process.

Yes, a fly has the potential to transmit diseases like many other insects, but the plan is to know a little more, not to trigger a case of mysophobia.

Source: Business Insider