Which microorganism type includes both helpful and harmful species?

Bacteria are a diverse group of microorganisms that include both beneficial and pathogenic species. This diversity allows them to play various roles in different ecosystems and applications. For instance, certain bacteria are vital for processes such as fermentation, which is used in the production of foods like yogurt and cheese, and they contribute positively to human health by assisting in digestion and synthesizing vitamins in the human gut.

Simultaneously, some bacteria can cause diseases in humans, animals, and plants, making them harmful. Pathogenic bacteria can lead to foodborne illnesses and various infections. The dual nature of bacteria – being both useful and harmful – emphasizes their significance in food safety practices, where understanding the balance and managing the risks associated with pathogenic bacteria is crucial for ensuring public health.

The other microorganism types mentioned have less variability in their roles; for example, viruses typically do not provide beneficial functions to human health, whereas fungi and protozoa also exhibit specialized roles that do not include as broad a range of both beneficial and harmful species as bacteria do.