Certified Cheese Professional Practice Exam

Which category does the substance Listeria monocytogenes fall under?

1. Bacteria

2. Protein

3. Enzyme

4. Acid

The correct answer is: Bacteria

Listeria monocytogenes is classified as a type of bacteria. This organism is a significant foodborne pathogen that can cause listeriosis, an infection that poses a particular risk to pregnant women, newborns, the elderly, and individuals with weakened immune systems. Understanding the characteristics of Listeria is critical in the context of food safety, especially in the cheese industry, where dairy products can become contaminated. Proper handling and pasteurization processes are essential to prevent the growth of this bacterium, underscoring the importance of microbial awareness in cheese production and storage. The other categories listed—protein, enzyme, and acid—do not accurately describe Listeria monocytogenes. Proteins are large molecules made up of amino acids, enzymes are proteins that catalyze biochemical reactions, and acids are substances that can donate protons (H+) in a solution. Since Listeria monocytogenes is an organism, its classification firmly falls under bacteria.