FOOD & WATER

Question 1

Why must Food and water must be continuously monitored?

Answer 1

for micro contamination to prevent human illness

Question 2

Water is monitored for?

Answer 2

Coliforms

Question 3

Coliforms are?

Answer 3

• Gram negative bacilli
• Lactose fermenters
• Do not produce endospores
• Normal flora Enterobacteriaceae

Question 4

What do Coliforms indicate?

Answer 4

Coliforms indicate that a water sample maybe contaminated with human waste and may contain pathogens

Question 5

Testing water for coliforms is a three step process…

Answer 5

Presumptive test
Confirmed test
Completed test

Question 6

Presumptive test is…

Answer 6

Lactose Durham tubes are used to 
determine MPN (most probable number)

Question 7

Confirmed test is…

Answer 7

EMB plate to check for Gram negative

lactose fermenters

Question 8

Completed test is…

Answer 8

Gram stain to confirm that the cells are

Gram negative bacilli

Question 9

Why not test for pathogens directly?

Answer 9

• Coliforms are more numerous than pathogens

- Coliforms are easier to culture in lab than pathogens

Question 10

What do you expect to see in lactose fermentation for food and water test?

Answer 10

Yellow is + for fermentation

Indicates Coliforms may be present