Eosine and Methylene Blue EMB
The test for Unknown 361 showed a pink color, which signified that the fermentation occurred very slowly and poorly.
Procedure:
1. Obtain an EMB agar plate
2. Streak it with the appropriate bacterial culture using the quadrant streak plate method
3. This will result in the isolation of individual colonies.
Starch Amylose / Amylopectin Test
The results for this test on the Unknown 361 were positive.
Procedure:
1. Use a fresh (16- to 18-hour) pure culture of test bacteria as an inoculation source.
2. Pick a single isolated colony and either single streak or spot inoculate the surface of the agar medium.
3. A single starch agar plate can be divided into four quadrants for four different inoculations except for
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Inoculate the test agar medium: There are two types of inoculation that can be done.
Phenol Red Broth – Glucose, Lactose, Sucrose
The test results are as follows: for glucose, lactose, and Unknown 361 tested A/-, meaning that acid was produced, but no gas and it tested K for sucrose meaning that there was alkaline production.
Procedure:
1. Obtain one tube for each sugar, usually one for glucose, lactose, sucrose, mannitol. Do not get them confused, they look the same, it is suggested that they be labelled immediately if they are not already labelled.
2. Observe the tubes before you begin. They should have an inverted Durham tube that is filled fully with broth (they are to test for gas production).
3. Do not use a tube if it does not have a full and inverted Durham tube or it looks wrong or contaminated.
4. Label each tube appropriately including the sugar initial if needed.
5. Use your wire loop to aseptically inoculate each tube with your unknown bacteria. Do not cross contaminate your tubes with the wrong sugar, flame your loop between inoculations.
6. Remind your instructor to set up un-inoculated control tubes. You will need these for a comparison. Place your tubes in the rack provided for this test. Your instructor will incubate