As the Yuletide and New Year celebrations fade and many households return to their regular routines, health experts are sounding the alarm over a common kitchen habit: leaving dirty dishes soaking in the sink overnight. While it may seem like a harmless or even helpful practice, researchers and microbiologists warn that it can turn kitchen sinks into breeding grounds for harmful bacteria linked to food poisoning and other serious illnesses.
According to experts, the combination of warmth, moisture and leftover food particles creates ideal conditions for bacteria to multiply rapidly. Plates, cutlery and pots left submerged in water for hours can become heavily contaminated, increasing the risk that germs will spread to hands, utensils, countertops and ultimately, food.
Jason Tetro, a microbiologist and author of The Germ Code, describes the kitchen sink as one of the most microbe-rich areas in the home. “As a microbiologist, I see the kitchen sink as a haven for microbes and microbial transfer,” he explains. “Studies have shown that the kitchen sink is the collection place for different types of unwanted bacteria, including fecal coliforms, foodborne pathogens and even skin bacteria.”
Research from Cardiff Metropolitan University supports this view. In a study that swabbed kitchen surfaces in 46 homes across the United Kingdom, scientists found that sinks contained more bacteria than any other area of the kitchen — including toilets in some cases. The researchers attributed this in part to how sinks are used, particularly for handling raw foods.
One risky habit highlighted by experts is washing raw poultry in the sink before cooking. Although many people believe this makes meat safer, food safety authorities warn that it actually spreads bacteria through splashing water, contaminating nearby surfaces, utensils and dishes.
Among the most common bacteria found in kitchen sinks are Escherichia coli (E. coli), Enterobacter cloacae and Klebsiella pneumoniae. E. coli, in particular, can cause severe illness, with symptoms including fever, vomiting and diarrhoea. Certain strains, such as Shiga toxin–producing E. coli, can lead to serious complications and are especially dangerous for young children, the elderly and people with weakened immune systems. Recent research has also linked E. coli to a worrying rise in colon cancer cases among people under 50.
Health experts warn that leaving dishes soaking overnight in warm water creates the perfect environment for these microbes to thrive. Even stacking dirty plates beside the sink is not entirely risk-free. Dr Brian Labus, a public health expert at the University of Nevada, explains that while dry environments may slow bacterial growth, they do not necessarily kill bacteria. “And if you have food sitting out, it can attract bugs that can spread bacteria to the rest of your kitchen,” he adds.
To reduce the risk of food poisoning, experts recommend washing dishes promptly rather than leaving them overnight. Using a dishwasher where possible is also advised, as the high temperatures are more effective at killing harmful microbes. Kitchen sponges, which are known to harbour large numbers of bacteria, should be cleaned regularly in the dishwasher or microwave, where heat can destroy germs.
The Food Standards Agency (FSA) also strongly advises against washing raw meat, warning that this practice spreads bacteria around the kitchen rather than removing it. Proper cooking, not washing, is what kills harmful pathogens.
These warnings come amid growing concern about food poisoning outbreaks, including recent cases linked to contaminated ready-to-eat foods such as supermarket sandwiches. While many infections, like those caused by Campylobacter, clear up within a week, severe cases can be life-threatening for vulnerable groups.
Ultimately, experts say simple changes in kitchen habits — including avoiding overnight soaking of dishes — can significantly reduce the risk of illness and help keep households safe.