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Escherichia coli (fluorescence) Petri Film instructions

First, the principle

The test plate contains a dry powder medium, a selective inhibitor, a fluorescent substrate, and a cold water soluble gel. The medium provides the nutrients needed for E. coli growth; the selective inhibitor can effectively inhibit the growth of other bacteria; when E. coli grows and propagates, the fluorescent substrate is decomposed and frees the fluorescent group, and the colony is blue-white fluorescent under the 365 nm ultraviolet lamp. .


Second, the packaging specifications

25 pieces / bag; 20 bags / box.


of LST, BGLB, EMB and other E. coli detected in the routine test.

1. Hydration test plate

Place the test plate on the surface of the water platform, uncover the upper film, add 1mL of diluted droplets to the culture layer, slowly cover the upper layer film, and place the grooved part of the liquid plate to the dilution area and place it on the upper layer. Press the plate evenly to spread the dilution evenly in the pressure ring and solidify for 20 minutes.

2. Vaccination

The hydrated test plate is placed on the surface of the water platform, and the upper layer film is uncovered. The inoculation needle picks up the spot to be tested on the test plate and covers the upper layer film.

3. Cultivation

The inoculated test plates were stacked (not more than 15 pieces) in a self-sealing pocket (not sealed), and cultured at 36 ° C ± 1 ° C for 8 h. The test plate should be placed in a flat place (a small piece of cardboard can be placed in the incubator), and it should not be placed directly on the wire frame to facilitate the deformation of the gel.

4. Results interpretation

After the completion of the culture, the test plate was taken out and observed under a 365 nm ultraviolet lamp in a dark room. The blue-white fluorescence was positive for E. coli (the colonies were blue-white dots with light blue-white fluorescence surrounding, which could be distinguished from other fluorescent interferences). The waste is treated by autoclaving at 121 ° C for 20 minutes.

5. Storage:

Store in a cool, dark place with a shelf life of 1 year; store in a self-sealing pocket at room temperature after opening, and use up within 1 month.


Third, sample inspection

Sample preparation

    Prepare sample dilutions according to the usual method (recommended dilution is sterile saline, phosphate buffer, sodium sulfite dilution and other sugar-containing dilutions are not allowed). 2-3 serial dilutions are presumed according to the number of E. coli in the sample. Spare.

2. Vaccination

Place the test plate on the surface of the water platform, uncover the upper film, suck 1mL sample and add the diluted droplets to the culture layer, slowly cover the upper layer film, align the grooved part of the liquid plate to the sample dilution area and place it on the upper layer film. The finger presses the liquid plate to spread the diluent evenly in the pressure ring. 2 repetitions per dilution.

3. Cultivation

The inoculated test plates were stacked (not more than 15 pieces) in a self-sealing pocket (not sealed), and cultured at 36 ° C ± 1 ° C. According to the E. coli activity in the sample, E. coli can be pre-judged in the sample from 8h to 12h, and accurate counting can be performed from 16h to 24h. The test plates should be placed in a flat place (a small piece of cardboard can be placed in the incubator), and it should not be placed directly on the wire frame to facilitate the deformation of the gel.

4. Count

After the end of the culture, the test plates was taken out and observed under a 365 nm ultraviolet lamp in a dark room. The blue-white fluorescence was E. coli (the colony was a blue-white dot with a light blue-white fluorescence around it, which could be distinguished from other fluorescent interferences), and the large intestine was selected. Test plates having a bacillus count of 10 cfu/tablet to 100 cfu/piece were counted. The waste is treated by autoclaving at 121 ° C for 20 minutes.

Fourth, the application of test strips in the identification of E. coli

    This test plate can be used to identify the intermediate links