Anti Bacterial Soap Vs Hand Sanitizer Lab Report

Introduction

Anti bacterial soap will kill more bacteria that grow on human hands than hand sanitizers. The purpose of this experiment is to determine which hand cleanser will kill more bacteria and to test the hypothesis. Both hand cleansers claim to kill bacteria efficiently. The Sanell brand hand sanitizer claims to kill 99.99% of germs that cause infectious illnesses (Catalog, 2009). Anti bacterial soap also claims to be 99.99% effective against bacteria and germs that cause illnesses (Antibacterial, 2009). After reading the claims by both products, I decided to research these claims before conducting the experiment. Over the course of 27 studies between regular soap and anti bacterial soap, the anti bacterial soap did not prove to kill more bacteria than regular soap (Preidt, 2009). They found that the anti bacterial soap did not contain enough triclosan, its main ingredient, to kill harmful bacteria (Preidt, 2009). The hand sanitizers remove the layer of oil on our hands, and this prevents the bacteria from under our skin from coming to the surface (Bailey, 2009). These bacteria do not cause illnesses and thus potentially increasing the amount of harmful bacteria that grows on our hands (Bailey, 2009). The FDA still suggests that hand sanitizer should not be used in place of soap and water (Bailey, 2000). After conducting this research on the two products, I hypothesized that the anti bacterial soap will kill more bacterial on human hands than the hand sanitizer will kill. The bacteria in this experiment will be grown on the nutrient agar. Bacteria need a source of food to survive and the agar feeds the bacteria and allows it to thrive. The bacteria from our hands will grow on the nutrient agar and we will be able to determine which method to cleanse your hands is the most effective at killing bacteria. If my hypothesis is supported, then the decrease in the number of bacterial colonies growing on the agar after washing our hands with anti bacterial soap will be greater than the difference in the amount of bacteria growing on our hands after cleaning them with hand sanitizer.

Methods and Materials

In order to conduct this experiment, we had to gather the necessary materials. Each person gathered two cotton swabs, a Petri dish containing the nutrient agar, a permanent marker, a small bottle of Sanell brand hand sanitizer, anti bacterial soap, and a small amount of sterile water. There were twelve students in our group, so we divided into two equal groups; one used hand sanitizer while the other used anti bacterial soap. After all of the materials were gathered, we were able to conduct the experiment. Each person evenly divided their Petri dish into two equal halves, using a permanent marker on the bottom of the dish. One side was labeled before treatment and the other side was labeled after treatment. Then, each person took one of their sterile cotton swabs and swabbed the thumb on their dominant hand. In order to do this, the cotton swab was first dipped in sterile water, and then it was twirled up and down each person's thumb on their dominant hand. After the cotton swab was twirled and the bacterial sample was gathered, we transferred the bacteria from the cotton swab to the Petri dish by twirling the cotton swab around on the "before" side of the Petri dish; this was the control group. First, the hand sanitizer group cleaned their hands. Each person used two drops of hand sanitizer and rubbed their hands together for 15 seconds, making sure to clean their dominant thumb. After our hands were dry, we needed to swab our hands again. We dipped the second cotton swab in sterile water and then used the same method to swab our dominant thumb and then transfer it to the Petri dish. We swabbed up and down once with the wet cotton swab then twirled it around in the "after" side of the Petri dish. For the group that used the anti bacterial soap, their procedure was a little different. The same procedure was used, except instead of using hand sanitizer, we used one pump of anti bacterial soap. We washed our hands for fifteen seconds under warm water with one pump of the anti bacterial soap. After the fifteen seconds were up, we then rinsed off the soap with warm water, and then took a swab of our dominant thumb. The swab was then swirled around on the "after" side of the Petri dish to transfer the bacteria from the swab to the agar. After we finished plating the two treatment groups (the hand sanitizer vs. the anti bacterial soap), we placed the Petri dishes filled with the bacteria in an incubator and incubated them at approximately