Dubai, United Arab Emirates (CNN) – A kitchen sponge contains more bacteria than a kitchen utensil brush, which may be a healthier way to clean dishes, according to researchers in Norway.
According to Trond Moretro, a research scientist at the Norwegian Institute of Food, Fisheries and Aquaculture also known as “Nofima”, salmonella and other bacteria grow and live on a sponge better than a kitchen brush and the reason is that a sponge never dries with daily use.
A single sponge can harbor more bacteria than humans on Earth, according to Moretro, author of the new study, which was published online in the Journal of Applied Microbiology.
While many bacteria are considered harmless, those bacteria – such as salmonella – can be spread by a sponge on the hands, kitchen surfaces and appliances and can make people sick.
“The sponge is wet and food waste accumulates on it, which is also food for bacteria, which leads to the rapid growth of bacteria,” explained Moretro.
However, what surprised the experts most about their findings is that it does not matter much how and how often you clean the sponge.
“The way consumers used the sponge does not matter much in terms of bacterial growth,” Moretro said, noting that “it is very difficult for consumers to avoid the growth of bacteria on the sponge as long as it is not replaced daily. “.
The research on used sponges and dish brushes is based on a laboratory study published last year by the same team of researchers, which found that harmful bacteria live on sponges longer than cleaning brushes.
In the United States, the USDA says microwave heating or boiling a sponge can reduce “some bacterial load,” but these measures alone are not enough to ensure less cross-contamination from your sponge.
The U.S. Department of Agriculture recommends frequent purchase of new sponges.
The research was part of an EU-backed project on food safety.
sponge vs brush
The researchers collected kitchen sponges from 20 people living in Portugal, and 35 brushes and 14 sponges were collected from people living in Norway.
A previous study of 9,966 people conducted by the research team found that sponges are commonly used to clean dishes in most kitchens in 10 European countries, with the brush being the predominant cleaning tool for cleaning in both Norway and Denmark.
All sponges were used for cleaning dishes, including dishes and pans for rubbing, and 19 out of 20 sponges in Portugal were used five to six times a week or more.
Among the dish brushes collected in Norway, 32 out of 35 brushes were used five to six times a week or more.
Sponges collected in Norway were used less frequently.
No disease-causing bacteria were found on the brushes or sponges.
However, bacterial levels were lower in the brushes used compared to sponges in general.
In cleaning dishes, similar types of non-pathogenic bacteria were found.
When researchers added salmonella bacteria to cleaning brushes and sponges, they found a significant reduction in the number of salmonella in mattresses that were left to dry overnight, but the bacteria were not reduced to mattresses stored in a plastic bag or sponge, regardless of storage conditions. .
The owners of the cleaning sponges and brushes used in the research showed how long they usually used these tools and how they stored their cleaning tools by rinsing them with water, washing them with soap and water or putting them in the dishwasher. .
However, none of these measures made a tangible difference – something that surprised experts. The main finding from the study was that cleaning brushes, which were left to dry between uses, had fewer bacteria.
Because the cleaning brush dries so quickly, Moretro said, harmful bacteria die. Most cleaning brushes also have a handle that prevents you from coming into direct contact with potentially harmful bacteria in your hand, unlike a sponge.
“I encourage consumers to try the cleaning brush next time they need to replace the sponge,” he added.
What to do
The study authors recommended using a brush instead of a sponge and Cath Reese, a professor of microbiology at the University of Nottingham who was not involved in the research, said she would continue to use the sponge to wash dishes.
For him, the main benefit of the study is that drying sponges is a good idea.
“The main message I found is that they did not find evidence of pathogenic bacteria in sponges or brushes from a number of local locations, so there is no evidence that these items are a significant source of contamination in normal home environments,” Reese said. .
Marcus Eggert, a microbiologist at the University of Furtwangen in Germany who conducted similar research, explained that he used a cleaning brush to wash his dishes, which he cleaned in the dishwasher.
If people prefer to use a sponge to clean their dishes, Eggert, who was not included in this study, recommends using a new sponge every two to three weeks.
He explained: “Brushes are the best alternative for cleaning dishes, from a hygienic point of view. This may have been expected before, but the authors of the study have proven this through some important experiments. However, based on my experience, people likes to use a sponge. “