EQUIPMENT--Fecal coliform determination

 
                                       November 26, 1969

QUALITY OF WATER BRANCH TECHNICAL MEMORANDUM NO, 70.05

To:     Regional Hydrologists and District Chiefs, WRD

From:   Chief, Quality of Water Branch, WRD 

Subject: EQUIPMENT--Fecal coliform determination

The Millipore Corporation Portable Waterbath Incubator 
(Catalog No. XX63 003 00) has been tested by G.F, Smoot's 
Unit, WRD, Arlington, Va., and the FWPCA Analytical Quality 
Control Laboratory, Cincinnati, Ohio. Results of both tests 
indicate that for ambient air temperatures from -1 deg C (30 
deg F) to 45 deg C (113 deg F) the Millipore Portable 
Waterbath Incubator will maintain the temperature specified 
(44.5 +/- 0.5 deg. C) for the fecal coliform determination. 
For ambient air temperatures exceeding 45 deg C, the 
temperature of the water in the incubator gradually increases 
and eventually exceeds the upper permissible temperature 
limit for the fecal coliform determination. Therefore, if the 
portable waterbath incubator is used in climates where the 
air temperature exceeds 45 deg C (113 deg F), air-conditioned 
vehicles, or some other independent method of lowering 
ambient air temperatures, should be used.

Test data also indicate that the water temperature is uniform 
throughout the water chamber. In summary, the Millipore 
Portable Waterbath Incubator will meet the temperature 
requirements for determination of fecal coliform in the field 
and laboratory in the range of air temperatures normally 
encountered.

Preliminary reports from several Districts indicate that the 
prepared nutrient ampoules for fecal coliform determination 
marketed by Millipore Corporation (MFC Broth medium Catalog 
No. M000-000-2F) may not give results comparable with those 
obtained using standard laboratory prepared media. Therefore, 
for the fecal coliform determination, commercially available 
dehydrated media is preferred instead of Millipore MFC Broth 
medium ampoules. Difco Laboratories, Detroit, Michigan, 
markets a dehydrated media (3228-09, dehydrated, MFC Broth 
base) that has received extensive use and approval by many 
microbiologists, and its use is recommended.



                                    W. H. Durum

WRD Distribution
A, B, FO-L, PO