Bacteria Q's URGENT DUE 12/5

[freefier4629]

Hi!
For my science experiment, I have to interview an expert. In my experiment, I am testing how well hand sanatizers, soap, and water kill bacteria. The three types of bacteria I am testing are Bacillus cereus, Euterobacter aerogenes, and Sarcina lutera. I was wondering if you could give me any information on these bacteria.

[michellebayefsky]

Dear freefier4629,

Welcome to sciencebuddies.com! First of all, I must note that the experts on this site are asked not to provide personal information (as you might require for your interview). But, of course, we are here to help as much as we can. Secondly, what specifically are you looking for in terms of information about the bacteria? The Science Buddies website has extremely useful information about how to grow bacteria and analyze agar plates (https://www.sciencebuddies.org/mentorin ... tion.shtml and https://www.sciencebuddies.org/mentorin ... ates.shtml). In addition, much information can be found about those specific types of bacteria on the Food and Drug Association website, Wikipedia, www.textbookofbacteriology.net, and other websites. Please let us know more specifically what you need to know, so that we can provide more detailed and helpful answers.

Hope this helps!

Michelle

[freefier4629]

Thanks! I have completed my experiment, and I was wondering if there was any additional things that could keep my experiment from being accurate. (My experiment is hand sanatizers vs. soap vs. regular water and i put the different chemicals on peices of coffee filter and put them in petri dishes) I was wondering if it would affect the experiment that the water that I used was put in on a coffee filter, and wasn't running water, like it would be if you were washing your hands

[freefier4629]

In addition, I was wondering if there was anything aditional that I might want to know the alcohol that was found in hand sanatizers, and how are some bacteria more resistant to hand sanatizer and soap than other bacteria?

Thanks!

[sunmoonstars]

Hi,

Good job on completing your experiment. Regarding your follow-up questions, I thin there are a few points in your experiemtn that would be different from a person actually washing their hands. You mentioned the running water - that is true. Also, the act of hand washing also provides a physical removal of bacteria from the hands (not just killing them) - this is not reflected in your experiment. Also, the amount of product used in the petri dish may not be the same as one would use on their hands.

I am not sure if anyone has tested these products on a wide range of bacterial species. Usually companies use the common ones to test their products, as described here (scroll down about half way) - http://www.clorox.com/products/faqs.php?prod_id=clb

let me know if this brings up any further questions.
Tonya

[freefier4629]

Thanks! I was wondering what exactly the companies would mean - did it kill the bacteria effictively (like 1tspb of hand sanatizer, or would would they mean that it could kill the bacteria, but you might have to use the hand sanatizer in large amounts? In addition, what other chemicals would companies add to their hand sanitizers to make them more effective than their competitors? Besides alcohol, I didn't see any other chemicals listed on the active ingredients list, so would that mean that they all really have the same level of effectiveness as long as they have the same amount of alcohol?

[sunmoonstars]

If a company makes a claim to the product killing bacteria, they have to supply the istructions to use it because (you are right), the killing will be dependent on how much product is used. For example, using the clorox link I provided above, they tell you how to prepare and use the solution to kill bacteria. If you do not do it the right way, you will not be killing the bacteria. For a product such as hand sanitizer, follow the instructions - I believe they state to rub the hands for a certain length of time and then allow to air dry. If you do not do this, the product will not be killing the bacteria.

For hand sanitizer, the active ingredient is usually alcohol (at approximately 70%). Yes, they will all have the same effectiveness if they have the same level of alcohol (or approximately the same). Any extra ingredients are usually to make the product smell better or feel better or to help in the manufacturing process. Some "natural" products may use an entirely different formulation to kill bacteria - usually containing herbs and plant derived substances with ot without alcohol.

This is a great topic! You probablly learned alot from this activity!

[freefier4629]

Thank you! I had one last question. I was wondering what the substance is that makes the hand sanatizer thick, and is there any advantage to using hand sanitizer over just distilled alcohol?

Thanks a ton!

[sunmoonstars]

This link has alot of FAQs that could help you. http://www.brands2liveby.com/purell/content/faq.htm

Here is another link that gives the ingredients list (I didn't have a bottle here to check) - http://www.raytechcatalog.com/product_i ... r-376.html

The glycerin gives the product its thickness.

An advantage of this product is that it contains moisturizers to help prevent drying of the skin. Straight alcohol is very drying to the skin.