Microbiology: Coliforms and Fecal Coliforms in Food

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What is the primary reason why coliforms are used as indicators of contamination?

They are the primary pathogens in foodborne illnesses
They are the most common type of bacteria found in food
They react similarly to pathogens in the natural environment (correct)
They are easily cultured and identified in a laboratory setting

What is the term for all members of the coliform bacteria group?

Klebsiella
Fecal coliforms
Total coliforms (correct)
Enterobacter

Which of the following foods is a common source of coliforms?

Pasteurized milk
White brined cheese (correct)
Cooked poultry
Canned vegetables

What is the characteristic of coliforms that allows them to be used as indicators of contamination?

Their ability to ferment lactose (B) Signup and view all the answers

What is the primary habitat of coliforms?

Soil and vegetation (C) Signup and view all the answers

What is the implication of detecting coliforms in food?

The food is contaminated with other pathogenic organisms (B) Signup and view all the answers

What is the primary function of the tetrazolium indicator in the Petrifilm EC/Coliform Count Plate?

To facilitate colony enumeration (A) Signup and view all the answers

Why is it essential to perform the presumptive test before the confirmatory test in coliform detection?

To ensure the statistical validity of the method (C) Signup and view all the answers

What is the purpose of the 5-bromo-4-chloro-3-indolyl-D-glucuronide (BCIG) in the Petrifilm EC/Coliform Count Plate?

To detect the presence of glucuronidase activity (D) Signup and view all the answers

What is the primary advantage of using the Petrifilm EC/Coliform Count Plate in food and beverage industries?

It reduces the time required for testing (D) Signup and view all the answers

What is the significance of Modified Violet Red Bile (VRB) nutrients in the Petrifilm EC/Coliform Count Plate?

It inhibits the growth of non-coliform bacteria (A) Signup and view all the answers

What is the primary implication of coliform contamination in food and beverages?

All of the above (D) Signup and view all the answers

What is the primary habitat of Escherichia coli bacteria?

Lower part of the intestines of humans and animals (A) Signup and view all the answers

What is the function of 0.1% peptone water in the detection of coliforms?

It is a minimal nutrient media designed to reduce multiplication of microorganisms (B) Signup and view all the answers

What is the significance of detecting fecal coliforms in food and water?

It indicates the presence and risk of pathogenic microorganisms (D) Signup and view all the answers

What is the purpose of using Lauryl sulfate tryptose broth (LSTB) in the detection of coliforms?

It is used for the presumptive testing for the presence of coliforms (D) Signup and view all the answers

What is the characteristic of Escherichia coli that makes it a member of the thermotolerant coliform group?

It can ferment lactose in 48 hours at 44.5ºC (B) Signup and view all the answers

What is the significance of recovering fecal coliforms from processed food?

It indicates post-sanitation and post-process contaminations (C) Signup and view all the answers