Which of the following bacteria can contaminate foods when shellfish are harvested from polluted waters?

Vibrio is the correct choice because it is a genus of bacteria that is commonly associated with seafood, particularly shellfish, especially when harvested from polluted waters. Shellfish can bioaccumulate Vibrio species, such as Vibrio cholerae and Vibrio parahaemolyticus, leading to illness in humans when consumed raw or undercooked. These bacteria thrive in warm coastal waters, making shellfish particularly vulnerable to contamination when environmental conditions are poor, such as during algal blooms or when sewage contamination occurs.

Understanding the context of shellfish harvesting is crucial here. When shellfish are collected from waters that are polluted with fecal matter or other contaminants, they can absorb harmful bacteria into their tissues. This poses a significant risk to public health, as these organisms can cause foodborne illnesses ranging from mild gastrointestinal discomfort to severe and life-threatening conditions.

The other choices, while also serious pathogens, do not have the same direct association with shellfish in polluted waters. Clostridium botulinum is primarily linked to improperly canned or preserved foods, whereas Salmonella and E. coli O157:H7 are typically associated with contaminated meats and produce rather than shellfish specifically. Hence, the focus here on Vibrio clearly identifies the bacteria that