"Lisa Moore" <lmoore from usm.maine.edu> wrote in message
news:mailman.24.1171993232.5139.microbio from net.bio.net...
>I teach a basic microbiology lab class and have included the phenol red
> fermentation test in the lab after the students do the
> oxidation-fermentation glucose test. I am trained as a phytoplankton
> ecophysiologist, so I am not familiar with this test outside of teaching
> this lab. From the various lab books and websites that I have looked
> at, the test is done in test tubes under aerobic conditions. My
> question is whether a non-fermenter can oxidize the sugars (such as
> lactose and sucrose) and turn the medium yellow (indicative of acid
> production), thus giving a false positive? It seems to me that this is
> possible, making the test rather limited. Of course, I could be missing
> something in understanding the protocol or chemistry behind the test.
>> If someone has a quick answer or a good reference, I would appreciate
> the help.
>> Thank you,
> Lisa
>> Lisa R. Moore
> Assistant Professor
> Department of Biological Sciences
> University of Southern Maine
> 96 Falmouth Street
> Portland, ME 04103
> email: lmoore from usm.maine.edu> phone: (207) 780-4261
> fax: (207) 228-8116
>
Never heard of the phenol red test in relationship to microbiology, do you
mean the methyl red (MR)test that is often performed in conjunction with the
Voges-Proskauer (VP) reaction to help distinguish E.coli from other
coliforms?
