Kitchen sponges are teeming with bacteria, and are even dirtier than toilets, researchers found.
A team at Furtwangen University in Germany analyzed 14 different kitchen sponges, and conducted a DNA analysis, New York Daily News reports. The analysis revealed 362 different kinds of bacteria in the sponges. Since sponges are moist almost all of the time and are made for absorption, they tend to pick up bacteria such as E. coli, salmonella and Staphylococcus when they are used to clean dishes, swab counters, or merely from hands touching them.
The study said,
Despite common misconception, it was demonstrated that kitchen environments host more microbes than toilets.
Sponges are “the biggest reservoirs of active bacteria in the whole house,” reports TIME.
While most of the bacteria present are not harmful, there were pathogens that could lead to certain infections in humans. Sponges are also able to spread bacteria to other clean places. The study stated, “Kitchen sponges are likely to collect, incubate and spread bacteria from and back onto kitchen surfaces, from where they might eventually find their way into the human body, e.g. via the human hands or contaminated food.”
The recommended ways to clean sponges thoroughly include microwaving them for a minute, soaking them in a bleach solution using hydrogen peroxide, ammonia, vinegar or isopropyl alcohol. All of these are said to kill at least 99.9% of bacteria.
However, the researchers found that microwaving sponges does not kill all of the potentially harmful bacteria, and any sterilizing method only reduces bacteria content by 60%. Also, some bacteria are actually able to resist sanitation and increase instead of dying out.
The best thing to do is to change kitchen sponges weekly to avoid contamination, the study concluded. Also, those who use loofahs a lot should be warned that these are also susceptible to bacteria build-up.
The study was published in Scientific Reports.