What is a key characteristic of pathogens?

A key characteristic of pathogens is their ability to cause disease in humans. Pathogens include a variety of microorganisms such as bacteria, viruses, parasites, and fungi, which can enter the body and disrupt normal physiological functions, leading to illness. This characteristic is fundamental to understanding food safety, as it highlights the importance of controlling and preventing contamination in foods to protect public health.

Other options do not accurately describe pathogens. While some pathogens may produce odors, it is not a reliable indicator for all, as many pathogens can be present without producing noticeable scents. Additionally, not all pathogens are visible to the naked eye; in fact, most are microscopic and require laboratory techniques for detection. Finally, while pathogens can be found in contaminated food, they are not exclusive to food sources and can also be present in water, surfaces, and other environments.