Alkaline Peptone Water (APW) is a liquid selective medium specifically designed for the enrichment culture of pathogenic vibrios. It selectively suppresses the growth of non-vibrio contaminants such as coliform bacteria and Salmonella through an alkaline regulatory mechanism (pH 8.6±0.2), while providing optimal proliferation conditions for alkalophilic vibrios including Vibrio cholerae, Vibrio parahaemolyticus, and Vibrio vulnificus.