The trick is to use saturated steam at 1 bar overpressure — a pressure cooker at 15 psi will do this — for 15-20 minutes. (Pharmaceutical grade autoclaves are just pressure cookers that operate on a large scale.) 1 bar overpressure corresponds to saturated steam at a temperature of 121 degrees celsius and it makes a real mess out of anything with a cell wall or proteins. This is a whole lot more effective than merely boiling your sponges at standard atmospheric pressure, let alone the microwave-and-pray method.
(Note: I'm going from third-of-a-century-old memory of pharmaceutical manufacturing standards here, rather than an actual citable source. Confirming it is an exercise for the reader and actual specifics may vary. A sterilized sponge, no matter how thoroughly boiled, may still contain residual toxic compounds left from bacterial decomposition. And as I allowed my professional registration as a pharmacist to lapse a long time ago this is not professional advice.)
When you kill bacteria via technique X, some bacteria are affected by it more than others. Since not all bacteria are killed, this leads to the enrichment of some types of bacteria.
When a scientist took the most populous bacteria and scoured the encyclopedia for any way in which this bacteria could possibly be dangerous, he finds that "It is widespread in nature and lives on the human skin. It can cause infections in people with weak immune systems.", which is about par for the course.
It always amazes me the traction this sort of story gets. We've been cleaning hands and dishes and counter tops with towels and sponges for hundreds of years, and the more we worry about the bacteria, the worse we make things.
Trust that we've evolved to live in bacteria filled environments and not die horribly.
I use mine to get food off of the dishes, and then rinse the dishes in running hot water. There's no way I'm expecting the sponge to be bacteria free.
A better headline for the article would be "most people don't know how to properly disinfect their stuff".
I did enjoy the comparison of used sponges with human feces, the article is definitely worth a read.
"Sanitation by boiling or microwave treatment has been shown to significantly reduce the bacterial load of kitchen sponges19, 21 and can therefore be regarded as a reasonable hygiene measure.
However, our data showed that regularly sanitized sponges (as indicated by their users) did not contain less bacteria than uncleaned ones. Moreover, “special cleaning” even increased the relative abundance of both the Moraxella– and Chryseobacterium–affiliated OTUs (Fig. 3B). Presumably, resistant bacteria survive the sanitation process and rapidly re–colonize the released niches until reaching a similar abundance as before the treatment (Fig. 6A). This effect resembles the effect of an antibiotic therapy on the gut microbiota40, 41, and might promote the establishment of higher shares of RG2-related species in the kitchen sponges.
Although further analyses, including controlled sanitation experiments, are needed to substantiate these findings, our data allow careful speculation that a prolonged application of sanitation measures of kitchen sponges is not advisable."
- "Microbiome analysis and confocal microscopy of used kitchen sponges reveal massive colonization by Acinetobacter, Moraxella and Chryseobacterium species" https://www.nature.com/articles/s41598-017-06055-9
I believe freezing is, however, extremely effective again parasites (but there won't be in the sponge though).
It can be as little as 4 minutes for steam at 270*F/~32 psi for medical instruments. That is usually for immediate-needs and 45 min cycles were more typical for what I had to do for a job. Boiling water isn't certainly going to do it.
It's probably safer and cheaper to just buy them in bulk and throw them away after a few days of usage than try to sterilize them.
(Our "flash" protocol is 10 minutes instead of four, but it probably depends on how heavily wrapped the item is).
The real problem with using bleach to clean dishes or eating utensils is that some of us can taste it very strongly, even hours or days later. For example, the first job I had was at a fast food place and we had one idiot who used bleach to soak the plastic soft drink dispenser nozzles in overnight, instead of the provided cleaning solution (which was tasteless). I was the only one working there who noticed but I knew every single time he did it without fail.
On the flip side, people who use hand sanitizer all the time? Yep. You guessed it. They end up having crappy immune systems as a result, and in some cases, toxicity from over-absorption of the hand cleaning chemicals such as Triclosan.
I use soap when washing dishes, and after I'm done, I just leave it there (I don't clean the soap from the sponge).
But soap doesn't just magically do this - it has to be foaming, as scrubbing allows the soap molecules to magnetically organize. As the hydrophobic soap molecules stick to the non-polar bacteria, they form a bubble shell that's not unlike a cell wall. To produce this foam with normal hand soap takes ~20 seconds of rotational scrubbing - a soap-Rasengan, if you will.
Bacteria are in everything, including every breath of air and gulp of water. Our immune system kills the ones which get through our small intestine's mesh system.
Do you have any links about this?
So, a damp sponge is a perfect environment for growing bacteria.
Now if you are using antibacterial soap your sponge may be fine like that, but then those soaps have concerns of their own (eg. They kill good bacteria that we apparently want to keep around)
> The U.S. Food and Drug Administration today issued a final rule establishing that over-the-counter (OTC) consumer antiseptic wash products containing certain active ingredients can no longer be marketed. Companies will no longer be able to market antibacterial washes with these ingredients because manufacturers did not demonstrate that the ingredients are both safe for long-term daily use and more effective than plain soap and water in preventing illness and the spread of certain infections. Some manufacturers have already started removing these ingredients from their products.
The reason why sponges are great for bacteria is their ability to hold water in little pockets. These dry out completely and much faster. The bacterial load won't be zero, but I suspect it will be much better than with sponges, especially with some judicious disinfecting. (Which I will be using the pressure cooker for!)