1. Characterization of Bacteria Responsible for Background Anomalies in the Enumeration of Fecal Coliform Bacteria by the Membrane Filter Technique Esther P. Tennant-Clegg Jerald D. Hendrix

2. Apogee Colony Counting System F Background interference caused by non-fecal coliforms interfered with both automated and manual fecal coliform enumeration.

3. Inconsistent Colony Counts F Two plates created from identical samples. F The plate on the left is overgrown with typical blue colonies formed by fecal coliforms F The plate on the right shows a zero fecal coliform count.

4. Bacteria Isolated from Water Samples on mFC agar: Typical and Atypical

6. Standard Membrane Filter Technique  0.45  m nitrocellulose filter F mFC Agar F Rosolic acid to inhibit background interference  Incubation at 44.5 ° C ± 0.5 ° C for 24 hrs in water bath F Plates are incubated in a watertight bag or box

8. Common Features of Atypical Bacteria on mFC F Produce higher pH (up to 8.5) in the mFC Agar F Agar turns transparent yellow F Aerobic F Non-fermentative F Not inhibited by rosolic acid

9. Methods Used to Identify Bacteria F Gram Stain F Wet mount slide to observe motility F Catalase and Oxidase Test F SIMS Agar to discover Indole reactions, and Oxygen requirements F Fermentation Tubes (Sucrose, Lactose, Glucose) F Oxiferm and Enterotube rapid biochemical test (Beckton Dickinson)

10. Limited Oxygen Incubation Method F Agar is poured close to the top lip of plate limiting the area between bacterial growth and lid. F Each plate is individually wrapped with parafilm prior to incubation. F All other aspects of the Standard Method of Membrane Filter Technique remain unchanged.

11. Effect Of Limited 0 2 on Background and Growth of E. coli Atmospheric O 2 Levels Limited O 2 Levels

12. Effect Of Limited 0 2 on Background and Growth of Atypical Isolates Atmospheric O 2 Levels Limited O 2 Levels