In each issue of Best Health magazine we look into whether product claims are valid, from beauty products to household cleaners.

In the May issue, with spring cleaning in mind, we took a look at sponges. Some are labelled antimicrobial or antibacterial. Does that mean they kill germs? We asked Dr. Donald Low, chief microbiologist at Mount Sinai Hospital in Toronto and spokesperson for the Healthy and Hygiene Council of Canada.

“We don’t know how effective the antimicrobials in these sponges may be,” says Low. “Some bacteria are resistant even to the most powerful drugs. The sponge may not stop the growth of illness-causing bacteria like salmonella. Indeed, when you read these products’ labels, they don’t claim to do that. They do claim to sop the growth of odour-causing bacteria.”

Any damp sponge is the perfect environment for bacteria to multiply. In just 20 minutes, bacteria such as salmonella can multiply to an amount that can make you sick. The best way to kill bacteria in sponges is to clean and dry them between uses.