METHOD OF ENRICHING AND DETECTING A TARGET MICROORGANISM
The present disclosure provides a method of detecting a target bacterium. The method includes forming a primary enrichment culture that includes a test sample, a primary enrichment medium and a redox dye; incubating the primary enrichment culture for a first period of time equal to eight hours or less; assessing the primary enrichment culture during the first period of time to detect whether the redox dye changes from a first state to a second state; if the second state is detected in the primary enrichment culture during the first period of time, mixing a portion of the primary enrichment culture with a secondary enrichment medium to form a secondary enrichment culture and incubating the secondary enrichment culture for a second period of time; and performing a test to detect the target bacterium using a portion of the second enrichment culture.
1 . A method of detecting a bacterium belonging to the genus Salmonella , the method comprising:
mixing a first volume of a test sample with a second volume of a primary enrichment medium to form a primary enrichment culture;
wherein the primary enrichment culture comprises a redox dye;
incubating the primary enrichment culture for a first period of time equal to eight hours or less;
assessing the primary enrichment culture during the first period of time to detect whether the redox dye changes from a first state to a second state;
if the second state is detected in the primary enrichment culture during the first period of time, mixing a first portion of the primary enrichment culture with a secondary enrichment medium to form a secondary enrichment culture and incubating the secondary enrichment culture for a second period of time; and
performing a test to detect the bacterium of the genus Salmonella using a second portion of the second enrichment culture.
2 . A method of detecting a bacterium belonging to the genus Salmonella , the method comprising:
mixing a first volume of a test sample with a second volume of a primary enrichment medium to form a primary enrichment culture;
wherein the primary enrichment culture comprises a redox dye;
incubating the primary enrichment culture for a first period of time equal to eight hours or less;
assessing the primary enrichment culture during the first period of time to detect whether the redox dye changes from a first state to a second state;
if the second state is not detected in the primary enrichment culture during the first period of time, incubating the primary enrichment culture for a third period of time; and
performing a test to detect the bacterium of the genus Salmonella using a third portion of the primary enrichment culture
3 . The method of claim 1 , wherein the redox dye is selected from the group consisting of methylene blue, resazurin, and tetrazolium
4 . The method of claim 1 , wherein a ratio of the first volume to the second volume is less than or equal to 10:1.
5 . The method of claim 1 , wherein the first state has a first color and the second state has a second color that is measurably different than first color.
6 . The method of claim 5 , wherein the first state is a colorless state and the second state is a colored state or wherein the first state is a colored state and the second state is a colorless state.
7 . The method of claim 1 , wherein the test sample comprises a component of the primary enrichment medium.
8 . The method of claim 1 , wherein the first period of time is equal to or less than 4 hours.
9 . The method of claim 1 , wherein assessing the primary enrichment culture during the first period of time comprises assessing the primary enrichment culture at a first time point and assessing the primary enrichment culture at a second time point after the first time point.
10 . The method of claim 1 , wherein assessing the primary enrichment culture during the first period of time comprises using an instrument to measure light absorbance or reflectance by the primary enrichment culture.
11 . A method of detecting a target bacterium, the method comprising:
mixing a first volume of a test sample with a second volume of a primary enrichment medium to form a primary enrichment culture;
wherein the primary enrichment culture comprises a redox dye;
incubating the primary enrichment culture for a first period of time equal to eight hours or less;
assessing the primary enrichment culture during the first period of time to detect whether the redox dye changes from a first state to a second state;
if the second state is detected in the primary enrichment culture during the first period of time, mixing a first portion of the primary enrichment culture with a secondary enrichment medium to form a secondary enrichment culture and incubating the secondary enrichment culture for a second period of time; and
performing a test to detect the target bacterium using a second portion of the second enrichment culture.
12 . The method of claim 11 wherein,
mixing a first volume of a test sample with a second volume of a primary enrichment medium to form a primary enrichment culture;
wherein the primary enrichment culture comprises a redox dye;
incubating the primary enrichment culture for a first period of time equal to eight hours or less;
assessing the primary enrichment culture during the first period of time to detect whether the redox dye changes from a first state to a second state;
if the second state is not detected in the primary enrichment culture during the first period of time, incubating the primary enrichment culture for a third period of time; and
performing a test to detect the target bacterium using a third portion of the first enrichment culture.
13 . The method of claim 11 , wherein the redox dye is selected from the group consisting of methylene blue, resazurin, and a tetrazolium dye.
14 . The method of claim 11 , wherein a ratio of the first volume to the second volume is less than or equal to 10:1.
15 . The method of claim 11 , wherein the first state has a first color and the second state has a second color that is measurably different than first color.
16 . The method of claim 15 , wherein the first state is a colorless state and the second state is a colored state or wherein the first state is a colored state and the second state is a colorless state.
17 . The method of claim 11 ,
wherein the test sample comprises a component of the primary enrichment medium.
18 . The method of claim 11 , wherein the first period of time is equal to or less than 4 hours.
19 . The method of claim 11 , wherein assessing the primary enrichment culture during the first period of time comprises assessing the primary enrichment culture at a first time point and assessing the primary enrichment culture at a second time point after the first time point.
20 . The method of claim 11 , wherein assessing the primary enrichment culture during the first period of time comprises using an instrument to measure light absorbance or reflectance by the primary enrichment culture.