Sterilization with UV Tools and Materials

STERILIZATION A.Sterilization with UV Tools and materials a. Petri dish b. Medium To be upright. c. UV lamp d. Bunsen Lamp Ways of working a. Melt 3 tubes of medium so that they stand upright in a water bath. b. Pour into 3 sterile petri dishes and let freeze. c. Illuminate the first petri dish with UV for 1 minute, the second dish for 3 minutes, and the third dish is not illuminated (open). d. Incubate the petri dish for 24 - 48 hours at 37oC, in reverse. e. Observe the growth of microbes in the three petri dishes. 3.3. Sterilization with chemicals Chemical substances such as alcohol, formalin, carbolic acid, lysol, soap, etc. can be used to sterilize tools. In this practicum, sterilization will be carried out using several chemicals. A. Sterilization with alcohol Tools and materials a. Sterile petri dishes b. Medium NA is upright c. Pins/small nails. d. Alcohol with concentrations of 40%, 70% and 96% e. Sterile water f. Tweezers Ways of workinga. Melt the NA medium in a water bath and pour into a petri dish. Let it freeze in the room. b. Soak the pin or nail in the alcohol solution above for 10 minutes. c. Wash the pin with sterile water and place it on the surface of the medium in the petri dish. d. Incubate at temperature 28 - 30oC for 24-48 hours. e. Compare the microbial growth around the pin. Which solution is most effective. f. Do the same thing using 4% formalin, lysol and carbolic acid. B. Sterilization with soap Tools and materials a. Sterile petri dishes b. Medium NA is upright c. Soap with various trademarks. Ways of working a. Melt 2 tubes of upright NA medium in a water bath and pour into two sterile petri dishes b. Rub your unwashed finger on the surface of the medium in the first petri dish. c. Wash your fingers with a certain brand of soap as clean as possible and let them dry by themselves (don't dry them with a cloth). Once dry, rub your finger on the surface of the medium in the second petri dish. d. Incubate the two petri dishes for 24-48 hours at a temperature of 28-30oC. e. Compare the microbial growth in the two petri dishes. 3.4. Sterilization with membrane filter Ingredients that should not be heated, such as serum and certain types of sugar, can be sterilized using a filter membrane. In the field of microbiology, the most widely used filter tools are Kerfield filters, Chamberland filters, Seilz filters, etc. These filters are made from a special polymer with a diameter of 0.45 microns, so they can retain bacteria contained in the sample. In this practicum you will use a membrane made from polysulfone, which is produced by Millipore. Tools and materials a. Polysulfone membrane with a diameter of 0.22 microns (hydrophilic) b. A set of membrane experiment equipment complete with gas regulator. c. Petri dish d. McCartney bottle e. Gun pipette complete with tips f. Medium NA is upright g. Polluted water Ways of working a. Melt the NA medium in a water bath and leave at a temperature of 40oC. b. Filter some polluted water (river water) using a polysulfone membrane. c. Pipette 1 ml. This filtered water and place it in a petri dish d. As a control, pipette 1 ml of unfiltered water and place it in a second petri dish. e. Pour each tube of NA medium (temperature 40oC) into each petri dish containing the water sample. f. Shake both cups in such a way that the sample becomes homogeneous with the medium, and let it freeze. g. Incubate the two petri dishes at a temperature of 20-30oC for 24-48 hours. h. Observe both petri dishes!!. What conclusions can you draw from this experiment?