New York City Food Protection Practice Test

Which bacterium is commonly carried by healthy humans?

1. Staphylococcus aureus

2. Bacillus cereus

3. Salmonella typhimurium

4. Clostridium botulinum

The correct answer is: Staphylococcus aureus

Staphylococcus aureus is commonly carried by healthy humans, and it is frequently found on the skin and in the noses of healthy individuals. This bacterium is part of the normal flora for many people and can exist without causing any harm. However, it has the potential to cause illness if it enters the body through a cut or wound, or if it is ingested through contaminated food, especially when proper hygiene practices are not followed. This highlights the importance of maintaining food safety and personal hygiene to prevent the spread of Staphylococcus aureus, which can lead to foodborne illnesses. In contrast, the other options represent bacteria that are not typically part of the normal human microbiota and are more associated with foodborne infections or environmental sources. For instance, Bacillus cereus can cause food poisoning but is usually linked to specific foods rather than being commonly carried by healthy individuals. Salmonella typhimurium is primarily associated with food contamination and is not typically found in healthy human flora. Clostridium botulinum, responsible for botulism, is not normally present in healthy humans and is mainly found in improperly handled foods or in the environment.