Coliform Bacteria Testing Results

The video tutorial demonstrates how to inoculate petri dishes with various water samples to test for fecal coliform bacteria. The instructor explains the process of using sterile pipettes to transfer water samples onto agar plates, which serve as a medium for bacterial growth. The video covers testing samples from different sources, including a pond, fish tank, tap water, and more. Results are analyzed to determine the presence of coliform bacteria, highlighting the importance of water quality and safety.

What is the purpose of using agar in petri dishes for this experiment?

• To provide a medium for bacteria to grow

• To sterilize the water samples

• To change the color of the bacteria

• To prevent contamination from the air

Why is it important to use a sterile pipette for each water sample?

• To make the water samples more visible

• To speed up the experiment

• To prevent cross-contamination

• To ensure accurate measurement

What was the result of the coliform bacteria test for the tap water sample?

• Negative with some beneficial bacteria

• Positive with one colony

• Negative with no colonies

• Positive with several colonies

Why did the fish tank water test negative for coliform bacteria?

• The water was boiled before testing

• There are no mammals in the fish tank

• The water was treated with chemicals

• The fish tank was recently cleaned

What was the result of the coliform bacteria test for the Santa Clarita River water?

• Negative with some beneficial bacteria

• Negative with no colonies

• Positive with two small colonies

• Positive with five large colonies

What was the result of the coliform bacteria test for the Gilbert Arizona riparian Preserve water?

• Positive with one colony

• Negative with some beneficial bacteria

• Negative with no coliform bacteria

• Positive with several colonies

What was the result of the coliform bacteria test for the bottled water sample?

• Negative with some beneficial bacteria

• Positive with several colonies

• Positive with one colony

• Negative with no coliform bacteria

What was the result of the coliform bacteria test for the ocean water in Oxnard?

• Negative with some beneficial bacteria

• Positive with several colonies

• Negative with no colonies

• Positive with one colony

What was the result of the coliform bacteria test for the Riverside pond water?

• Positive with several colonies

• Positive with one colony

• Negative with no colonies

• Negative with some beneficial bacteria

Why is it advised not to drink creek or stream water without purification?

• It is too turbid to see through

• It is too cold to drink

• It may contain coliform bacteria

• It has a bad taste