Posts tagged: bacteria

Cleaning a Dirty Sponge Only Helps Its Worst Bacteria, Study Says

Cleaning a Dirty Sponge Only Helps Its Worst Bacteria, Study Says
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Since the advent of dishwashers, there are homes that don’t use sponges to clean their eating utensils and cookware anymore. However, in homes that do still use the old sponge, dishwashing soap, and running water, keeping your sponge “clean” is an anomaly in itself. Since the sponge is constantly washed with soap and water shouldn’t it be always clean? Wrong. A sponge is the perfect breeding ground for bacteria, which requires two important things to thrive: a (1) warm (check!) and (2) wet (check!) environment.

If you do a web search on how to sanitize your sponge, you will find various articles that cite microwaving it can kill off most of its bacteria. Michigan State University and the US Department of Agriculture actually encourage sanitizing sponges by microwaving, which reportedly kills 99.9 percent of bacteria living on it. However, a recent study by found that while microwaving, boiling, or other similar methods of cleaning the sponge may indeed kill off bacteria, it can only kill the weaker, heat-susceptible bacteria. The stronger strains of bacteria like the Moraxella osloensis lives on despite microwaving and will actually spread to the areas where the weak bacteria used to be. This is precisely why sponges will eventually start to smell or emit a foul odor despite sanitizing them regularly. [1]

The study was led by Markus Egert and his team and they analyzed the microbiome found in kitchen sponges. Driven initially by their interest in the microbial diversity of the organisms found in kitchen environments, the team actually found that kitchen sponges harbored abundant numbers of pathogens. Furthermore, they found that microwaving sponges affected the microbiome greatly… and (your health) negatively. [2]

The Pathogens In Your Kitchen Sponge

In any home, there are two places that are used the most: the kitchen and the bathroom. The researchers focused on these two because of their potential as “microbial incubators” because of how innately warm and moist they are. The kitchen sponge is actually a good representation of a kitchen or bathroom, because of its warm and moist environment. Furthermore, the sponge is constantly in contact with food and skin, which can carry pathogenic organisms that stick to and colonize in the sponge. The researchers were able to identify 362 different species of bacteria in 14 sponges, where there were roughly 82 billion bacteria in one cubic inch of sponge.

Analysis of kitchen sponges revealed three recurring bacteria: Acinetobacter, Moraxella, and Chryseobacterium species, all of which are pathogenic or pose a threat to human health. The second specie, Moraxella¸ was also commonly found on kitchen surfaces like the sink, faucet, refrigerator doors, and stoves — which exponentially increase human risk of being contaminated by them because those four things in the kitchen are the most touched and used (especially by kids!). Moraxella osleonsis is responsible for a number of infections that affect the skin and respiratory tract (including pneumonia). [2][3]

Because the population has become more conscious of our environment, you may turn your nose up at the thought of disposing of an item that can still be used and creating waste. However, your sponge is a lost cause. The more you try to clean it, the dirtier it actually gets! You can kill weak bacteria but that only allows the stronger, more dangerous pathogenic organisms to thrive all over the spaces the weak bacteria used to live. By trying to save your sponge, you are exposing yourself and your loved ones to the risk of a health-threatening infection. So think twice before tossing your dirty kitchen sponge in the microwave or washing machine to be “cleaned”. It’s safest just to get yourself a new sponge.

Sponges (the typical non-natural type) don’t biodegrade readily. For environmental reasons, look into natural or biodegradable sponges (not the easiest to find!) that will cut down on environmental pollution.


[1] Sanitizing kitchen sponges. Michigan State University.

[2] Cardinale, M. (2017). Microbiome analysis and confocal microscopy of used kitchen sponges reveal massive colonization by Acinetobacter, Moraxella and Chryseobacterium species.

[3] Maruyama, Y., et. al. (2017). Bacteremia due to Moraxella osloensis: a case report and literature review.

How The Bacteria In Our Gut Influence Our Minds

How The Bacteria In Our Gut Influence Our Minds
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Can’t focus? Feeling anxious or depressed? Easily stressed? It turns out the common phrases, “butterflies in the stomach” and “having a gut feeling,” have scientific truths. Researchers have discovered complex bidirectional communication between the brain and the gut. Some scientific sources have even gone as far as referring to the gut as the “second stomach” – and rightfully so. Read on for more on the intriguing relationship between mental health and gut microbes.

How Do Bacteria Alter the Brain?

You’ve probably heard that the brain is the most complex object in the known universe. So how does a bunch of bacteria in your gastrointestinal system influence such a sophisticated and powerful organ?

The intricate link between the digestive system and the brain is facilitated by the vagus nerve. This cranial nerve is part of the gut-brain axis that extends from the brainstem to gut, via lungs, esophagus, and heart. Interestingly, up to 90% of the vagus nerve is exclusive to the gut-brain communication network. So where do the bacteria come into play?

Your gut bacteria break down your dietary intake into short-chain fatty acids that enter the bloodstream. In turn, the blood releases hormones and neuroactive compounds that stimulate the brain, affecting various functions. According to a study [1] published in the Journal of mSystems, gut microbes can even influence gene expression through microRNAs.

The Impact Of Imbalance In Gut Bacteria

According to an article appearing in the Harvard School of Public Health [2], there are trillions of microorganisms or microbes in the human body, with the gut claiming the biggest share. This complex network of microbiota consists of both harmful (pathogenic) and helpful (symbiotic) microbes. Although these two categories typically coexist peacefully, the balance can be disturbed by anti-biotics, certain diets, and infectious diseases.

Dysbiosis or an imbalance of harmful and healthy gut bacteria is linked to a host of neurological health issues ranging from stress, depression, anxiety, autism to neurodegenerative diseases such as Parkinson’s or Alzheimer’s. For a better understanding of the importance of the gut-brain connection, consider the following research studies:

• According to a study [3] published in the Journal of Psychology, “germ-free” mice produced up to 2 times the amount of stress hormone in comparison to a “normal mice” that were in contact with microbes.

• In another study [4], researchers concluded that their findings supported a connection between Autism Spectrum Disorders and the gut microbiome’s influence on the brain. They went on to support the idea of probiotic treatment to address pathogenic bacteria in the GI and improve autism behavioral symptoms.

What are the implications of the elaborate gut-brain connection? In the words of Hippocrates, “All disease (including mental disorders) begins in the gut.” This suggests that medical experts could leverage the power of microbes and a healthy gut to treat or prevent neuropsychiatric and neurological disorders.


[1] Yuan, C., Burns, M. B., Subramanian, S., & Blekhman, R. (2018). Interaction between host MicroRNAs and the gut microbiota in colorectal cancer. MSystems, 3(3), e00205-17.

[2] The Microbiome. (2019).

[3] Sudo, N., Chida, Y., Aiba, Y., Sonoda, J., Oyama, N., Yu, X. N., … & Koga, Y. (2004). Postnatal microbial colonization programs the hypothalamic–pituitary–adrenal system for stress response in mice. The Journal of physiology, 558(1), 263-275.

[4] Hsiao, E. Y., McBride, S. W., Hsien, S., Sharon, G., Hyde, E. R., McCue, T., … & Patterson, P. H. (2013). The microbiota modulates gut physiology and behavioral abnormalities associated with autism. Cell, 155(7), 1451.