Certified Cheese Professional Practice Exam

What type of microorganism is Psychrotrophic classified as?

1. Bacteria

2. Protein

3. Enzyme

4. Acid

The correct answer is: Bacteria

Psychrotrophic microorganisms are classified as bacteria that can thrive in cold environments, typically at temperatures below 20°C (68°F). These bacteria are capable of growing at low temperatures and can be significant in food preservation and spoilage processes, especially in refrigerated goods. Their ability to metabolize and produce enzymes at lower temperatures allows them to retain activity even in conditions where most other bacteria may not thrive. In the context of cheese and dairy products, psychrotrophic bacteria can lead to spoilage if not managed properly, affecting the quality and safety of the products. These bacteria are often responsible for off-flavors and changes in texture, and they can produce heat-stable enzymes, making their impact lasting even after the product has been heated. The other options — protein, enzyme, and acid — do not accurately categorize psychrotrophic as they represent different concepts. Proteins are large biomolecules essential for structure and function in living organisms, enzymes are specific types of proteins that act as catalysts in biochemical reactions, and acids refer to compounds that can donate protons in solution. None of these options encompass the classification of psychrotrophic organisms in the context of microbiology.