Appeal No. 1997-1770
Application No. 08/235,488
detecting medium (see claim 17) which includes a
$-D-galactosidase substrate and a carbohydrate metabolizable
by a plurality of coliform species but not metabolizable by E.
coli. Independent claims 1 and 17 are reproduced below as
representative of appellants’ invention.
1. A method for detecting coliform bacteria and E.
coli, said method comprising the steps of:
(a) contacting a bacterial colony with a $-D-
galactosidase substrate;
(b) contacting said bacterial colony with a first
carbon source metabolizable by a plurality of
coliform species but not metabolizable
by E. coli, wherein metabolism of said first
carbon source provides a reaction product at
said colony;
(c) detecting a first reaction product signal of
said $-D-galactosidase substrate at said
colony;
(d) detecting a second reaction product signal of
said carbon source at said colony; wherein the
absence of both said first and second
reaction product signals indicates the
presence of non-coliform bacteria in said
colony, the presence of said
first and absence of said second reaction
product signal indicates the presence of E.
coli in said colony, and the presence of
said first and
second reaction product signals indicates the
presence of non-E. coli coliform bacteria
in said colony.
2
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