9.6: EMB Media Procedure
EMB Media Procedure
Name: _____________________________________________________
Course Section: ______________________________________________
The following activity will teach students how to inoculate an EMB agar plate. Post-inoculation, students will use their colony growth to determine if the bacteria are gram-positive or gram-negative, identify fecal coliforms, and verify lactose fertilization.
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| Procedure |
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Step 1:
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Step 2:
Step 3:
Step 4:
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Results
In the table below, record your observations for colonies grown in EMB media.
| Results Table | ||||||
| Bacterial Species | Growth (+/-) | Gram (+/-) | Colony color(s) | Lactose Fermentation (Y/N) | Coliform Species (Y/N) | |
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Escherichia coli |
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Proteus mirabilis |
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| Enterobacter aerogenes | ||||||
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Staphylococcus epidermidis
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General Questions
1 . What types of bacterial species is EMB used to identify?
2. How is EMB a selective medium?
3. How is EMB a differential medium?
4. Define coliform.
5. Explain the roles of the two dyes in EMB.
6. Explain the role of lactose in EMB.
7. Why is it important to test water samples for the presence of coliforms?
8. If you inoculate EMB agar using water sample from a facet, and dark purple/black colonies grow on the media, what does that indicate about the water sample?