Which organization is not required to list fluoride content on bottled water labels?

The Food and Drug Administration (FDA) is the organization that regulates bottled water, but it does not mandate the listing of fluoride content on bottled water labels. While the FDA sets guidelines for bottled water quality and safety, it does not have specific requirements for the disclosure of fluoride levels, unlike other constituents that might be mandated for disclosure under different regulatory frameworks.

In contrast, the Environmental Protection Agency (EPA) establishes regulations concerning the safe levels of contaminants, including fluoride, in public drinking water, but it does not govern bottled water. The World Health Organization (WHO) provides international guidelines and recommendations regarding water quality standards, but it does not directly regulate labeling policies. The Centers for Disease Control and Prevention (CDC) focuses on public health and safety but does not have regulatory authority over bottled water labeling either.

In summary, the FDA's lack of requirements for fluoride content on bottled water labels is why it is the correct answer in this context.