Despite their unsavoury habits, fruit flies may not pose a significant health risk if they land in your wine, according to scientific evidence. These tiny insects are known to frequent decaying food sources, potentially carrying harmful bacteria like E. coli, Listeria, Shigella, and Salmonella on their bodies. The concern arises when they deposit these microbes in your beverage.
The wine typically contains 8% to 14% ethanol and has a pH level of around 4 or 5, making it acidic. Ethanol, found in alcoholic beverages like wine, is known for its germ-inhibiting properties, contributing to wine's preservation. Various studies have demonstrated that combining alcohol and organic acids in wine, such as malic acid, can hinder the growth of harmful bacteria like E. coli and Salmonella.
The infectivity of germs in wine depends on factors such as the quantity of bacteria deposited (known as the "infectious dose") and their metabolic fitness. Additionally, chilling wine can disrupt the metabolic processes of some food-poisoning bacteria, inhibiting their growth.
Since all types of wine possess natural antibacterial properties, the germs introduced by fruit flies are likely to be damaged, reducing their ability to cause an infection. Even if some bacteria remain intact, wine is acidic, and stomach acid can further damage their DNA and potentially kill them. The human stomach also contains digestive enzymes, mucus, and immune defences that provide additional barriers against infection, making it highly unlikely for fly-deposited wine germs to establish an infection.