Presence-Absence Broth is used in microbiological testing to detect the presence or absence of coliform bacteria, including E. coli, in water, food, and environmental samples. It is particularly applied in testing drinking water, tap water, and other sources to assess contamination and water quality. The broth supports the growth of target organisms, with visual confirmation through color changes, turbidity, or gas production indicating microbial presence. Ideal for qualitative yes/no analysis as an indicator of sanitation. Commonly used in public health standards for water quality control, often followed by confirmatory tests for precise identification.