Health and Medicine
PUBLISHED
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What’s in a fart? This question, far from rhetorical, was one put to Dr Karl Kruszelnicki in the early 2000s. A nurse had asked if quietly farting during an ongoing operation could be considered a contamination of the sterile field.
The rest of this article is behind a paywall. Please sign in or subscribe to access the full content.“I realised that I didn't know,” Kruszelnicki told Brisbane’s Triple J radio. “But I was determined to find out.”
Farts, known to science as flatulence, are a fact of life. We have seen evidence of the passing of wind in fish, sloths, and certainly humans. Hardly surprising when you consider the internal marble run that is our digestive system.
When we eat, digestion begins in the mouth as we chew up food. Enzymes in our saliva help to break it down further, and our gut mixes it all together with acid until it forms a substance called chyme.
In the small intestine, our pancreas and liver lend a helping hand, providing enzymes and bile that help further break down what we’ve consumed. Whatever nutrients are released get absorbed, and before long it’s on its way out of our bodies in the form of feces.
It’s a complex process that produces gas through two key processes. There’s the air we swallow when eating, known as aerophagia. Then there’s the way certain foods get broken down by bacteria in our large intestine, AKA the colon.
That gas escapes through our rectum and is released into the air. It’s normal and healthy in most cases, but there’s no getting away from the fact that a fart must pass through a valley of bacteria on its way out into the world. So, does any of it hitch a ride?
To find out, Kruszelnicki visited microbiologist Luke Tennent, and together they devised an experiment. Tennent asked a colleague to fart into Petri dishes under two conditions: fully clothed and butt-naked.
The next day, they inspected the Petri dishes to look for differences. The resulting dish from the clothed condition didn’t show any signs of bacteria. Meanwhile, the dish that was on the receiving end of the bare-arsed fart had developed two types of bacteria found in the gut and on the skin.
“Our deduction is that the enteric zone in the second Petri dish was caused by the flatus itself, and the splatter ring around that was caused by the sheer velocity of the fart, which blew skin bacteria from the cheeks and blasted it onto the dish,” said Kruszelnicki. “It seems, therefore, that flatus can cause infection if the emitter is naked, but not if he or she is clothed.”
Kruszelnicki adds that his experiment with Tennent wasn’t a cause for concern either way (except, maybe, from an HR perspective). The bacteria the investigation did yield were the “good guys,” and not dissimilar to varieties found in yogurt. Their takeaway on the infectious potential of farts?
“Don't fart naked near food.”
You got it.
