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Unformatted text preview: orange biohazard bag. 8) After a 15 minute hold time on the bench, invert the Petri dish and place in a 37C incubator (plates may be stacked to a maximum of 3 high). 9) Remove gloves and wash hands before leaving the lab. 10) Incubate for 24+/-2 hours at 37C. 11) Put on gloves 12) Remove Petri dish from incubator and place it agar side down on the back-lit plate counter. Remove the lid from the Petri dish and adjust the magnifying lens so that you can see the colonies clearly. 13) Count all of the colonies (multiple colonies that are touching each other are counted as one colony). 14) Record your count in your notebook and take to the next class meeting. 15) Calculate the original bacterial density using the following equation: CFU/mL= (plate count/0.100mL)/dilution factor Example: (150 colonies / 0.100mL) / 10-6 = 1.5 x10 9...
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- Fall '09
- Environmental Engineering