Quality control sample of Escherichia coli in drinking water (membrane filter method)|BNCC378435 |BNCC

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Standard quality control samples of escherichia coli in drinking water

Culture medium	Peptone: 10.0, beef powder: 3.0, sodium chloride: 5.0, agar: 15.0,pH: 7.3±0.1(25 ℃)
Subculture procedure	① According to the culture conditions, the bacteria are first cultured into a bacterial suspension; ② Measure the absorbance of the bacterial suspension and calculate the initial concentration of the bacterial suspension according to the standard formula; The initial concentration multiplied by the survival rate is the actual concentration after freeze-drying; ④ According to the actual concentration after freeze-drying, the bacterial suspension was diluted to obtain the target concentration, and then subpacked and freeze-dried;
Growth conditions	37 ℃;18-24h; aerobic;
Growth characteristics	G-bacilli, positive for lysine decarboxylase and ornithine decarboxylase, negative for arginine dihydrolase, negative for urease and phenylalanine deaminase, IMViC test: +, +,-,-; positive for MUG, negative for cellobiose, negative for lateral marigold, positive for ammonium glucose; no H2S production, fermentation of lactose to produce acid and gas. facultative anaerobic, optimum pH7.4 ~ 7.6.
Storage conditions	-20 ℃
Safety level	1
morphology	The colony has a diameter of 1-2mm, round, neat edges, opaque, yellow front, light color, raised in the middle, smooth surface, easy to provoke, G-(red), bacilli
application	GB/T5750.12-2023 -12-Standard Test Methods for Drinking Water-Part 12: Microbiological Indicators
Sharing mode	Public welfare sharing