The world is chock full of germs that would love to live in your warm, food-rich interior. If allowed, they’d move in, eat your food, change your TV channels, poop on your carpet, and generally trash the place. I use the term ‘germs’ in the widest possible way, to encompass all of those microbes that can make a person sick: bacteria, viruses, protists, fungi. This piece is about methods for protecting you and yours; and like players at Fantasy GermWarfare we’ll sort out which matchups are favorable and which hopeless.
Kinds of sanitizers/sterilizers/cleaners:
My mother would never forgive me if I didn’t start with soap and water. The bad news: It doesn’t kill a danged thing. The good news: That’s not how it’s supposed to work. It’s supposed to separate you from the germs; allow them to wash off. The soap does a good job if you do a good job with the washing, no matter what type of germ. A downside or two from the prepping perspective is that it works best with warm water (to help fats and oils wash off) and it takes a lot of clean water. There’s not a lot of point in washing germs off of your hands using water that brings in reinforcements.
The next line of defense is often the alcohol gels. These can be just alcohol (usually isopropanol, so no one’s tempted to ingest it), or alcohol with an additional toxic-to-germs additive such as chlorhexidine. Alcohol at 70% kills everything but spores, which are bacteria that have gone inactive to ride out bad conditions. Killing everything but spores is quite useful, but obviously imperfect. Chlorhexidine by itself is very good against most kinds of germs, but spores, mycobacteria (such as the ones that cause tuberculosis) and some viruses are unharmed. Put the chlorhexidine in the alcohol and you have a good answer with one important caveat: Neither one of these works well if there’s a lot of organic matter (read, dirt) still on the skin or other surface being treated.
You can also use an alcohol wipe or rinse and it’s pretty effective; just use enough that it has a chance to work before it evaporates off.
Bleach is highly effective, working against almost everything. High concentrations are needed to kill spores. It’s often used at 1 part commercially available bleach (a 3 – 8% solution of sodium hypochlorite) to 9 parts water as a wipe solution where biological contamination needs to be eliminated. It’s wonderful stuff in some ways, but some people find it very irritating and it is not very shelf-stable.
Iodine, such as in the solution they wipe your arms down with before you donate blood, is highly effective against a wide range of organisms. It does stain; and more centrally it doesn’t have a nice long shelf life unless you buy the commercial preparations that include stabilizers. Nice for skin decontamination.
Hydrogen peroxide works against everything, but is only so-so against Gram negative bacteria. Those germs include E. coli and other varieties often responsible for diarrhea, respiratory infections, and urinary tract infections, so that’s a rather important soft spot in hydrogen peroxide’s game. It also decomposes fairly easily. It is good against the Gram positive bacteria such as the Staph infections that often cause skin trouble.
Triclosan is the extra active ingredient in ‘antibacterial’ soaps. It’s best against Gram positive bacteria. There never was evidence I could find that soaps with the triclosan actually prevent illness any better than soaps without it; and the FDA just banned it for toxicity. ‘Nuf said?
Which should you use to wash out wounds?
There’s some disagreement on this point, so let’s sort it out a bit.
First, every source I looked at agreed that rinsing wounds with something was vital; and that clean water was an acceptable choice.
Every source I’ve looked at that’s not twenty years old or more agrees that harsh cleaners are counterproductive, as they damage the exposed, live cells of the host just as much as any invaders. I’ve never seen bleach recommended by a reputable source, for example.
In between it’s fuzzier. As I attempt to draw some sort of consensus out of it, I concluded that for pretty clean wounds I’d stick to water, but upgrade to a gentle soap/warm water for a dirtier wound. Going with hydrogen peroxide (normal pharmacy grade, 3%) for a really dirty wound wouldn’t be unreasonable, but I wouldn’t do it.
So, which of these would succeed in making a wound nice and sterile?
None of them. Anything harsh enough to kill every germ is too harsh to put on live tissue. Getting and maintaining a true sterile field in a home probably just isn’t happening. The realistic goal is to be hygienic enough that the victim’s immune system can deal with whatever’s left.