We clean and disinfect the used dishes in the dishwasher, we clean the kitchen surfaces, we wash the floors and we forget, too often, probably the most contaminated object in the house, the sponge! Yet the sponge is an indispensable tool for cleaning and hygiene, it helps to get rid of stubborn dirt, removes food residues and makes the work table usable again. And yet… today we will see how sponges are a receptacle for bacteria to pay attention to and that the risk, thinking of cleaning kitchen surfaces, is instead of contaminating them with pathogenic bacteria! However, we will also try to understand what we can do to protect our health and that of our loved ones, treating kitchen sponges with a little more attention.
Sponges, a true receptacle for bacteria
Sponges are one of the major sources of pathogens that can be found in a kitchen. We pass the sponges on dishes and saucepans, where they can collect food residues, on surfaces, such as the work table, oven, refrigerator, sink and even the floor, where they collect potentially toxic microorganisms. And then the sponges are often summarily rinsed and, still wet, placed in a corner until the next use. In these conditions, sponges become real receptacles for bacteria that can thus contaminate surfaces, the foods they come into contact with and our hands, potentially putting our health at risk. But what are these bacteria that can be found in sponges and kitchen brushes? Studies conducted on sponges taken from real kitchens have shown that sponges can be contaminated not only by fungi and molds, but also by Escherichia coli, Salmonella, Staphylococci, Klebsiella and other bacteria that can attack the respiratory, urinary and gastrointestinal tracts, with symptoms such as vomiting and diarrhea (Osaili et al, BMC Public Health, 2020 - Wolde et al, Int J Food Sci, 2016).
Sponges, tips and best practices
We have seen that sponges and kitchen brushes are a source of bacteria, even pathogenic for the body. So let's see what we can do to make sponges a cleaning tool again. A first tip to avoid possible contamination caused by sponges is not to use the same sponge to clean the sink, oven and refrigerator and at the same time also to treat the work surfaces with which the foods we will soon eat come into contact. The sink, in fact, is one of the places most contaminated by bacteria. Just think of the wrong habit of rinsing the chicken breast under water, with the risk of distributing the meat bacteria in the sink. But even washing fruit and vegetables under running water, which is a correct practice, leads to the release of bacteria in the sink or other surface. Sponges soon become full of bacteria and leaving them unused for a few days at room temperature does not reduce their bacterial load (Osaili et al, BMC Public Health, 2020). Then, another piece of advice is to use brushes where possible. Indeed, brushes dry easier and faster than sponges and this causes the faster death of bacteria (Moretro et al, Int J Food Microbiol, 2021). Not only that, a good practice, both for sponges and brushes, is to change them often, especially if used to clean the residues of raw foods such as meat. However, it is known that sponges and brushes are also used because they are reusable and therefore are a money-saving choice. Therefore, until the next change of brushes and sponges, it is good to follow some hygiene rules to disinfect these very important kitchen tools. To disinfect sponges and brushes it is possible to boil them in water or even place them to wash in the dishwasher, and then let them dry well in the air (Moretro et al, Int J Food Microbiol, 2021). If you have a microwave at home, you can put the wet sponge in a microwave-safe container with a little water in it, place it in the microwave for a minute at maximum power, then reuse the sponge once it has cooled. Do not use this method for sponges with metal parts. Microwaves and dishwashers are the best methods for removing almost all bacteria, in fact 99.99% of bacteria are removed, as demonstrated by a research conducted in 2007 by the Agricultural Research Service center, part of the US Department of Agriculture (Sharma et al, USDA, 2007).
Kitchen sponges, treatments that don't work
There are other remedies, commonly used at home to disinfect sponges, such as dipping them for a minute in a solution containing 10% bleach, or for a more natural alternative in lemon juice. However, the American study mentioned in the previous paragraph (Sharma et al, USDA, 2007) showed that these remedies are ineffective for removing bacteria.
