Culture medium for separating enterococcus and streptococcus from milk sample and preparation method of culture medium

Abstract

The invention discloses a culture medium for separating enterococcus and streptococcus from a milk sample and a preparation method of the culture medium. The culture medium is used for separating enterococcus and streptococcus simultaneously and comprises components as follows: 15-25 g of bacterial peptone, 2-5 g of yeast, 2-5 g of beef heart extract or beef extract, 1-3 g of glucose, 1.8-2.5 g of sodium chloride, 0.3-0.5 g of disodium hydrogen phosphate, 2.0-3 g of sodium carbonate, 12-20 mg of nalidixic acid, 1.2-2 mg of polymyxin B, 0.1-0.3 mg of crystal violet, 2-5 g of aesculin, 0.3-0.8 g of ferric citrate and 10-18 g of agar, and the strain culture temperature is in a range from 35 DEG C to 37 DEG C. The culture medium has the advantages that the overall separation process is simple, visual and fast, the culture medium can separate enterococcus and streptococcus from the milk sample simultaneously, pathogen species are directly positioned to specific species or genuses, and the downstream analysis and identification process is simplified greatly. Besides, the invention further provides a culture medium component for independently separating streptococcus from the milk sample.

Description

technical field [0001] The invention belongs to the biological field, in particular to a culture medium for isolating bacteria from milk samples. Background technique [0002] The currently available systems for the isolation and identification of Enterococcus and Streptococcus in dairy products include the VITEK bacterial identification system and the API20E bacterial identification system. The principle is to integrate a variety of biochemical identification tests for Gram-positive bacteria on a standardized carrier (such as 96 Orifice plate), by inoculating bacteria, machine, or human-assisted machine reading and comparison with the result judgment library (table), so as to distinguish different bacterial species. Efficient preliminary sorting of target bacteria that need to be detected and monitored is the basis for rapid and accurate downstream identification. Enterococci widely exist in the environment, the digestive tract of animals and humans. With the natural evol...

AI Technical Summary

Problems solved by technology

However, there is currently no general-purpose medium that can separate enterococci in milk samples and also differentiate streptococci, and has a color reaction.