Expert reveals truth on whether you should still have your drink if fly lands in it

There have been some tentative moves into pub gardens thanks to the evenings getting lighter and the weather getting warmer, but soon we’ll be fully underway with some genuine summertime.

We’re also being treated to the first wave of insects, with wasps and bees starting to buzz about and some bluebottles making their 2025 debuts before their date with some rolled-up newspaper.

Fruit flies gravitate towards rotting waste

But what if one of those little blighters end up in your pint or Pimm’s? There’s no saving them once they’re in there, especially if it’s a boozy beverage they’ve submerged themselves in, but can you carry on drinking it once you’ve picked the bug out?

If you’ve spent any time considering what insects get up to, particularly flies, you’ll be unsurprised to learn that they might be harbouring some diseases.

Primrose Freestone, a senior lecturer in clinical microbiology, stressed that many insects are predisposed to hanging out around rotting material.

“They inhabit rubbish bins, compost heaps or any place where food is present, including drains,” she wrote in The Conversation, referring specifically to fruit flies. “Rotting food is rich in germs, any of which a fly can pick up on their body and transfer to where it next lands.”

As such, they might be carrying such nasties as E coli, listeria, shigella, and salmonella. Scrumptious.

However, alcohol has a sterilising quality. Wine, for example, tends to be between eight and 14% ABV, with an acidic pH of four or five.

“Several laboratory studies have also shown that the combined effects of wine alcohol and organic acids, such as malic acid, can prevent the growth of E coli and Salmonella,” said Freestone.

“Whether the germs transmitted by the fruit fly into the wine can cause an infection depends on the number of bacteria deposited (the ‘infectious dose’) and how metabolically fit the germs are.”

If that isn’t inspiring much confidence, then fair enough. While wine might kill off the germs, Freestone is careful not to say that it absolutely will.

While the alcohol will damage the bacteria to extent that it won’t make you ill, anything that survives the wine bath will be capable of messing with your system.

That said, stomach acid is pretty potent stuff and it’s capable of killing many food or drink-borne bacteria on its own. Digestive acids, enzymes, mucus, and immune systems are pretty solid lines of defence, but obviously they aren’t foolproof.

Not the brightest bee in the hive (WIN-Initiative/Neleman/Getty Images)

If you’ve ever had the squits after hitting the local chicken shop, you’ll know that plenty of bacteria are more than capable of weathering your defences and setting about making you sick.

Of course, if it isn't an alcoholic drink, there's no pre-drinking sterilisation going on.

Nevertheless, Freestone said: “I would suggest removing the fly and drinking the wine. If you want the extra protein, you could even swallow the fly.”