Best way to compare antibacterial soaps?

[dancingflower]

My teacher said the best way to compare different soaps would be to expose my hand to something with bacteria (like a piece of raw chicken), wash it with Brand A antibacterial soap, swab it, and smear a petri dish; then wash my hand and start all over again with Brand B soap, and so on. This sounds like a lot of hand-washing. Would the results be skewed by (1) the excess hand-washing and (2) layer upon layer of antibacterial soap? Is there some material I could use that would simulate my hand (a rubber stress ball, for instance), so I could start with a "clean" environment for each soap. If I were testing five different soaps, I would use five separate "hands" (balls) so that each soap wouldn't affect the others. Does it matter? Would a rubber stress ball be a good substitute for my hand? Or should I just use my hand and wash it each time? I need to submit my procedure by next week, and I also need to order the necessary supplies right away. Thank you.

[Grace]

Hi there,

Before you do anything - PLEASE, PLEASE, PLEASE do NOT use raw chicken as your bacterial source. The bacteria on uncooked chicken are known for causing infections that can seriously harm you - including Salmonella and Campylobacter. See these links for more information:
http://www.health.state.mn.us/news/pres ... 72006.html
http://www.consumerreports.org/cro/food ... ick_ov.htm

A much safer alternative (which will still give you bacteria to work with, but is not as dangerous to you as raw chicken) would be to rub your hands on something like lunch meat (fresh from the refrigerator, not sitting out for a long time) or even the sides of a sink in your home.

Antibacterial soaps are designed to work on your hands, so if you are worried about the effects of different soaps lingering on your hands, then you could swab your hand both before AND after washing. This way, you can compare before and after using a certain soap. If all of your "before" swabs produce about the same amount of bacteria, then you can probably compare all the "after" results as well. Your experiment would involve doing a modified version of what you said: (1) Touch some surface, (2) Swab your hand ("before"), (3) Wash your hands, (4) Swab your hand again ("after"), and then repeat steps 1-4 for each soap you want to test.

Remember to keep as many things constant/controlled as possible. The only thing you want to test is the different soaps, so keep everything else the same (how long you wash your hands, who's doing the hand-washing, water temperature, what you touch to get bacteria onto your hands, etc.).

Hope this helps!
Grace

[adance]

These are some good questions you came up with, I can tell you are really thinking about this experiment.
Grace's suggestion about doing before and after samples is good, then you'll know how clean your hands were before the experiment. You would want to be careful to wash your hands thoroughly each time so you get all the soap off. If you're worried you could also do the experiment at the same time every day, a different soap each day. Overall though I think you have a good plan.

[dancingflower]

Thank you for your suggestions. Is raw chicken really that dangerous even if I seal the petri dishes with scotch tape? Also, a similar experiment said to rub a piece of lunch meat all over a cutting board and leave it overnight, then swab it before and after I clean it with 409. Is that safer or worse than raw chicken?

[tdaly]

Yes, raw chicken is that dangerous. As was mentioned before, raw chicken often contains bacteria that can make you very, very sick - sick enough to go to the hospital. Sometimes these bacteria kill people. PLEASE DO NOT USE RAW CHICKEN for this experiment.

Lunch meat is not made of chicken. It is made of other kinds of meat, which usually don't have bacteria that are as dangerous as the ones in raw chicken.

I would be much, much more comfortable with you doing "a similar experiment said to rub a piece of lunch meat all over a cutting board and leave it overnight, then swab it before and after I clean it with 409." Like Grace said, make sure that the meat is "fresh from the refrigerator, not sitting out for a long time."

It is going to be very important as you do this experiment that you do it safely. If you have ANY questions at all about how to be safe doing this project, PLEASE let us know so that we can help you.