Rapid E. Coli O157:H7 Chromogenic Medium for Food Testing

Description

E. Coli O157:H7 Chromogenic Medium

Overview
E. Coli O157:H7 is a pathogenic strain of E. coli that can cause severe foodborne illness. The development of E. Coli O157:H7 Chromogenic Medium allows for rapid detection of this bacterium in food and patient stool samples. Laboratory personnel can effectively identify the target bacteria by observing the different colors of colonies formed on the medium.

Medium Composition
This medium includes the following components (grams per liter):

• Special Nutrients: 68.4g
• Chromogenic Reagents: 2.6g
• Agar: 15.0g
• pH: 7.0 ± 0.1 (at 25°C)

These components work together to create a suitable growth environment, ensuring the rapid proliferation of the target bacteria.

Preparation Method
To prepare this medium, first dissolve 17.2g of the powder in 200mL of distilled water and heat it for about 2 minutes. This process ensures thorough mixing for complete dissolution. Next, cool the solution to 45-50°C. Then, add CT additives while mixing thoroughly. Finally, pour the mixture into Petri dishes. Keep the prepared medium dry and incubate it at 36 ± 1°C for 2-4 hours before use.

Detection Steps
For detection, follow these steps:

1. Prepare sample solutions according to national standards, SN standards, or FDA guidelines.
2. Transfer 25g of the sample into 225mL of mEC Broth or mTSB medium and incubate it for 18-24 hours at 36 ± 1°C.
3. Use a 3mm inoculation loop to take samples from the enrichment broth and streak them onto two O157 chromogenic media plates.
4. Observe the colony colors on the plates. O157:H7 colonies should appear bright red, pink, or red without a blue halo.

Quality Control Measures
To ensure accuracy, implement quality control measures. Use the prepared medium within 2-5 days and keep it away from direct light. Additionally, store powdered media in a dry, dark place at 2-8°C to prevent degradation.

Conclusion
The E. Coli O157:H7 Chromogenic Medium serves as an efficient and reliable laboratory tool for quickly screening pathogenic E. coli. With simple procedures and clear results, this medium plays a crucial role in food safety testing. However, to ensure accuracy, further serological and biochemical testing remains necessary. Overall, the effectiveness of this process makes it an indispensable tool in the fields of food testing and public health.

Visit our [Chromogenic Medium Series] for more related products.