Coliforms are a broad group bacteria mostly found in the intestines of warm blooded animals. While these organisms are not typically associated with serious illness themselves, they are often used as indicator organisms. The presence of coliforms may indicate a possible presence of other pathogenic or disease-causing organisms. With this easy to use and economical test kit, students simply add a small amount of collected water to a sample tube and incubate for 24-48 hours. A distinct color change indicates that coliforms are present. The kit contains instructions and enough tubes to perform 25 tests.