The culture medium used is M-FC enriched, lactose medium containing
(2) The incubation temperature is 44.5oC, which requires incubating the
petri dishes by submerging them, enclosed in a plastic bag, in a water bath.
(3) Fecal coliform colonies are blue in color, whereas nonfecal colonies are
gray to cream-colored.
b. Fecal Streptococci. Fecal streptococci (enterococci), though not members
of the coliform group, are normal inhabitants of the intestines of humans and other
warm-blooded animals. Since the flora of the human digestive tract is predominantly
fecal coliforms while that of animals is predominantly fecal streptococci, a comparison of
the two groups present in a water sample may assist in determining whether
contamination is of human or animal origin. To test for fecal streptococci, the following
modifications are made to the standard procedure:
The culture medium used is M--Enterococcus Agar.
The incubation period is 48 hours.
Fecal streptococcus colonies appear as pink or dark red colonies.
Section II. BACTERIOLOGICAL STANDARDS
a. Standards. Conducting bacteriological tests on water supply samples is only
a part of the control measures for ensuring a potable water supply. For these tests to
have meaning, they must be interpreted against a set of standards. The standards for
military water supplies are established by the following documents:
(1) The National Primary Drinking Water Regulations. These regulations
promulgated by the EPA in accordance with the provisions of the Safe Drinking Water
Act (Public law 93-523), are mandatory minimum standards for potable water. The
regulations replaced the Public Health Service Drinking Water Standards of 1962. The
National Primary Drinking Water Regulations (NPDWR) established primary maximum
contaminant levels (MCL) for various contaminants that are directly related to safety of
drinking water. Other parameters are listed in the Secondary Drinking Water
Regulations relate to aesthetic quality.
(2) T8 MED 576. Sanitary Control and Surveillance of Water Supplies at
Fixed and Field Installations. This document provides guidance to all personnel
concerned with the production and surveillance of potable waters at either fixed or filed
activities. It includes procedures for inspections, correction of sanitary defects,