Most bacteria present in the environment are considered:

The majority of bacteria found in the environment are classified as nonpathogenic, which means they do not cause disease. These bacteria often play essential roles in various biological and ecological processes, such as decomposing organic material, contributing to nutrient cycling, and maintaining the balance of ecosystems. Many nonpathogenic bacteria are also beneficial to humans; for example, they can be found in the gut microbiome, where they aid in digestion and contribute to overall health.

Nonpathogenic bacteria can outnumber pathogenic bacteria significantly in natural settings, making them crucial for sustaining life and promoting a healthy environment. By further understanding the role of nonpathogenic bacteria, students in cosmetology can appreciate the impact these microorganisms have on skin health and hygiene practices, especially when considering how products or practices might affect the skin's natural microbiome.