Which bacterial group indicates fecal contamination or sewage pollution?

The correct answer centers on the role of coliform bacteria as indicators of fecal contamination or sewage pollution. Coliforms are a group of bacteria commonly found in the intestines of warm-blooded animals and humans. Their presence in water supplies or food indicates that the environment may be contaminated with fecal material, which could contain harmful pathogens. Therefore, testing for coliform bacteria is a standard practice in assessing the safety of water quality and ensuring that public health standards are met.

While the other bacterial groups listed have their significance in other contexts—Pseudomonas, for instance, is associated with opportunistic infections, and Salmonella is often linked to foodborne illness—they do not serve as reliable indicators of fecal contamination. Therefore, coliform bacteria are specifically recognized for their utility in signaling the potential presence of pathogens, making them the appropriate choice for indicating sewage pollution.