| After-sales Service: | 1 Years |
|---|---|
| Warranty: | 1 Years |
| Type: | Biochemical Test Paper |
| Material: | Paper |
| Application: | Water Test |
| Certification: | ISO |
| Customization: |
|---|
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Audited Supplier Product Description
Product name: Anti-corrosion coliform test paper
Product Code: 060090s
SPEC: 10 packs/box (9 pieces/pack)
Application: For the detection of coliform in food, beverage and health products containing preservatives (including benzoic acid, sorbate and its salts).
Test principle:
The nutrient adsorbed on filter paper is used as the culture substrate of coliform. Coliform can ferment lactose in the medium to produce acid, so that the bromomethyl powder purple indicator turns yellow from purple. TTC in the culture medium is reduced by bacteria to form a red colony that can be easily identified. Preservative antidepressant can eliminate the interference of preservatives (2.0g/L benzoic acid, sodium benzoate, sorbate, potassium sorbate); Through aseptic treatment, the packaging can directly detect coliform bacteria in food and drink pure water.
How to use:
1. Sample treatment: Put 25mL (or 25g) of the sample into a sterilized glass bottle containing 225mL sterilized normal saline or other diluent in aseptic operation (with an appropriate number of glass beads preset in the bottle), and make a uniform diluent of 1: :10 after full oscillation or grinding. Solid samples are best treated with a homogenizer for 1min at a speed of 8000-10000r/min to make a uniform diluent of 1:10; Absorb 1mL of 1:10 diluent with 1mL sterilizing pipette and inject it into a test tube containing 9mL of sterilized saline or other diluent to make 1:100 uniform diluent, and then make 10 times increasing diluent successively according to the previous step.
2. Inoculation: According to the requirements of food hygiene standards or the estimation of sample contamination, select the diluent with appropriate dilution, absorb three 10mL pieces and smear them on three bags of large paper; 3 pieces of 1mL were coated on 3 bags of small paper; Take another 1mL and dilute it 10 times, absorb three 1mL pieces and smear them on 3 bags of small paper. Then gently flatten the paper with your hand; The bags were cultured vertically in a constant temperature incubator (35-37ºC) for 18-24h, and then the results were observed.
3, Result interpretation: Negative result: the paper remains purple blue unchanged, whether there are red spots or red halo are judged as coliform negative. Positive result: red spots or red halo on the paper, yellow around it or yellow on the whole paper are judged as coliform positive.
4. Result report: Check the corresponding coliform MPN table according to the number of positive scraps, multiply the obtained data by the dilution factor, and report the MPN value of coliform in every 100mL (g) sample as a result.
1.Offering Sample for Testing .
2.R & D team to provide technical support.
3.Provide packaging, labeling OEM customization.
Q1:
Sometimes color of dehydrated culture media between batches have subtle differences,would this affect test results?
A1:The source and storage conditions of raw material is different ,so there may be a slight difference in color, which is a normal phenomenon. Products from our company have to undergo a rigorous inspection and sensory biology verification before sale, to ensure that all the indicators characteristics of the product is under enterprise standard to the extent permitted, not affect the test results.
Q2:
After pouring the liquid medium on the plate , medium seems hard to clot or coagulation time is longer, is it some problem with product quality?
A2: The reason may be:
The required hydration in the preparation process have not been done completely .That is to say distilled water is not boil sufficiently to dissolve agar. Because agar proportion, easily settle in the bottom of the bottle, if not fully shaken after high-temperature sterilization, it will lead to uneven upper agar culture gene content and difficult to set.
Q3:
Why some colonies of E. coli chromogenic medium color not shown above, but also confirmed through biochemical tests for E. coli (false negative)?
A3: E. CHROMOGENIC medium is based on the principle of specific enzyme of E. coli and design, 94% of E. coli have β- glucuronidase enzyme, with the chromogenic enzyme substrate medium role in the formation of blue-green colonies. And about 4% of the E. coli does not have β- glucuronidase enzymes, including concern O157: H7 Escherichia coli. Therefore, these E. coli can not be displayed on the color characteristic of E. coli chromogenic medium,it is possible of false-negative on the chromogenic medium. However, the traditional medium of the same can not avoid the problem of false negatives, such as: no gas or slow ferment lactose intolerance may also strain 44.5 false negatives in the conventional medium. For this small part of the E. coli can be detected using other methods.
Q4:
During anaerobic or micro-aerobic culture, is it necessary to remove gas bag from package? How to use oxygen indicator?
A4: During anaerobic or micro-aerobic culture, using method of gassing agent should be done according to the manufacturer's instructions. Remove the paper bag from the plastic packaging, but do not cut the paper bag. Torn the outer packaging of oxygen indicator then it can be used.
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