Section 1
Ubiquity of Microorganims
Number the plates 1 through 8 .
Open plate number 1 and expose it to the air for 30minutes or longer. Set it aside and out of the way ofthe other plates.
Use the cotton swab to sample your desk area andthen streak plates 2 and 3 in the pattern shown inFigure 2-1. (Pressing very lightly, roll the swab onthe agar as you streak it.)
Cough several times on the agar surface of plate 4.
Rub your hands together, and then touch the agarsurface of plate 5 lightly with your fingertips. (Alight touch is sufficient; touching too firmly willcrack the agar.)
Remove the lid of plate 6 and vigorously scratchyour head above it. (Keep this plate away from plate1 to avoid cross-contamination.)
Leave plates 7 and 8 covered; do not open them.
Label the base of each plate with the date, typeof exposure it has received, and the name of yourgroup.
Invert all plates and incubate them for 24 to 48hours at the following temperatures:Plates 1, 2, and 8: 25°CPlates 3, 4, 5, 6, and 7: 37°C
Using the plate diagrams on the Data Sheet, drawthe growth patterns on each of your agar plates. Besure to label them according to incubation time,temperature, and source of inoculum.
Save these plates in a refrigerator for use in Exercise2-2.