Colony Count Test Film
The total number of colonies refers to the samples obtained after being treated and cultured under certain conditions 1mL (g)
The total number of colonies contained in samples or units per unit area is the most commonly used microbial testing project.
The total number of colonies is a pre test piece for making disposable medium products prepared,
nutrient medium containing standard, cold water soluble gel and chloride (TTC dehydrogenase indicator threeTTCThe colony is red on the test film, thus reducing counting time and enhancing counting effect. The product is suitable for the determination of total bacterial count in various food and food raw materials, and can also be used for detecting the total number of colonies on the surface of food processing containers, operating tables and other equipment. Implementation standards: national standards for food safetyMicrobiological examination of foods – Determination of colony countGB/T 4789.2-2010).
Operation method :
Two point one Sample handling : take samples 25mL(Put in, contain225mLA sample tank or homogenized cup of normal saline is made1:10Sample mix, if necessary1mol/LNaOHor1mol/L HClSolution adjustment sample homogenizationPHto6.6~7.2. use1mLSterile pipette aspiration1:10Sample homogenization1mLInject into9mLIn the test tube, the shaker becomes shaken1:100Sample, liquid, and so on1:1000Uniform dilution of the sample, change a pipette every time.
Two point two Vaccination: general food selection2~3Dilution test, liquid samples containing less bacteria (such as drinking pure water and mineral water, etc.)
can be directly absorbed from the liquid for testing.
Test the total number of colonies
Place on a flat test table, uncover the upper membrane and draw with a sterile pipette 1mL
The sample is evenly dispersed and applied to the paper,
and then the top film is slowly lowered and placed aside 10s About to solidify the medium,
and inoculate two tablets each dilution.
At the same time, make a blank negative contrast.
Two point three Culture:
the test pieces are folded together and returned to the original self sealing bag and sealed.
The transparent faces are positioned upwards and horizontally in a constant temperature incubator,
and the number of the stacked pieces is not more than 12 Slice.
The average food culture temperature is 36C+1C. culture 15~24 Hours;
the culture temperature of aquatic products is30C+1C. culture 48 Hour.
3 Result interpretation
The bacteria showed red spots on the test film, and the number of colonies was moderate 30~300
The number of bacterial colonies in each milliliter (or per gram) of the sample is counted and multiplied by the dilution factor.