GB/T 4789.8-2003 Microbiological examination of food hygiene--Test for Yersinia enterocolitica

This standard specifies the test method for Yersinia enterocolitica. This standard is applicable to the test for Yersinia enterocolitica in various types of food and food poisoning samples. GB/T 4789.8-2003 Food Hygiene Microbiological Test Yersinia enterocolitica Test GB/T4789.8-2003 Standard Download Decompression Password: www.bzxz.net

ICS 07.100.30
National Standard of the People's Republic of China
GB/T4789.8--2003
Replaces GB/T4789.8—1994
Microbiological examination of food hygiene-Examination of Yersinia enterocolitica2003-08-11 Issued
Ministry of Health of the People's Republic of China
Standardization Administration of the People's Republic of China
2004-01-01 Implementation
GB/T4789.8—2003
This standard amends GB/T4789.81994 "Microbiological examination of food hygiene. This standard is mainly modified as follows compared with GB/T4789.8—1994: Examination of Yersinia enterocolitica". The standard text format and text are modified in accordance with GB/T1.1-2000. - Modify and standardize "equipment and materials" in the original standard. From the date of implementation of this standard, GB/T4789.8—1994 will be abolished at the same time. This standard is proposed and managed by the Ministry of Health of the People's Republic of China. The drafting unit of this standard: Nutrition and Food Safety Institute of China Center for Disease Control and Prevention. The main drafters of this standard: Wang Shuying, Zhou Guilian, Fu Jian, Yang Baolan. This standard was first issued in 1984, revised for the first time in 1994, and this is the second revision. 54
1 Scope
Food Hygiene Microbiological Examination
Enterocolitis Yersinia Examination
This standard specifies the examination method for enterocolitica Yersinia. This standard is applicable to the examination of enterocolitica Yersinia in various types of food and food poisoning samples. 2 Normative References
GB/T4789.8--2003
The clauses in the following documents become the clauses of this standard through reference in this standard. For any dated referenced document, all subsequent amendments (excluding errata) or revisions are not applicable to this standard. However, the parties to the agreement based on this standard are encouraged to study whether the latest versions of these documents can be used. For any undated referenced document, the latest version shall apply to this standard. GB/T4789.1 General principles for food hygiene microbiological examination GB/T4789.28—2003 Food hygiene microbiological examination staining method, culture medium and reagents 3 Equipment and materials
3.1 Refrigerator: 0℃~4℃.
3.2 Constant temperature incubator: 36℃±1℃, 4℃±1℃.26℃±1℃. 3.3 Microscope: 10×~100×.
3.4 ​​Homogenizer or sterile mortar.
3.5 Rack-plate pharmaceutical balance: 0g~500g, accurate to 0.5g. 3.6 Sterile test tube: 16mmX160mm, 15mm×100mm. 3.7 Sterile pipette: 1mL (with 0.01mL scale), 5mL, 10mL (with 0.1mL scale). 3.8 Sterile conical flask: 500mL, 200mL. 3.9 Sterile culture blood: 90mm in diameter.
0.5mL syringe. Www.bzxZ.net
Sterile knife, scissors, tweezers, etc.
3.12 White mice: 12g~15g.
4 Culture medium and reagents
4.1 Modified phosphate buffered saline (PSB): in accordance with 4.46 of GB/T4789.28-2003. 4.2 CIN-I culture medium: in accordance with 4.47 of GB/T4789.28--2003. 4.3 Modified Y culture medium: in accordance with 4.48 of GB/T4789.28-2003. 4.4 Modified Krebs: in accordance with 4.49 of GB/T478928-2003. 4.5 Sorbitol, rhamnose, sucrose, mannitol and other fermentation tubes: in accordance with 3.2 of GB/T4789.28-2003. 4.6 Ornithine decarboxylase broth: in accordance with 3.12 of GB/T4789.28-2003. 4.7 Semisolid agar: in accordance with 4.30 of GB/T4789.28-2003. 4.8 VP reagent: in accordance with 3.4 of GB/T4789.28-2003. 4.9 Sterile mineral oil.
4.10 Alkaline treatment solution: 0.5% chloride-0.5% potassium hydroxide mixed solution. 55
GB/T4789.8--2003
4.11 Urea culture medium: in accordance with 4.38 of GB/T4789.28-2003. 5 Inspection procedures
The inspection procedures for Yersinia enterocolitica are shown in Figure 1. Test sample 25g (mL) + 225mL modified phosphate buffer 4℃
Meat and its products, other foods
Alkali treatment, 15s, 4.5mL + 0.5mL sample solution
I7d, 14d, 21d
Inoculate CIN-I. Improved Y medium
26℃, 48h
Pick suspicious colonies, inoculate modified Klebsiella double 26c
Urease test
Semisolid
26℃, 24h; 37℃, 24h
Biochemical typing
6 Operating steps
6.1 Sample collection and processing: See GB/T4789.1. Samples should be sent for inspection as soon as possible after collection. Milk and its products
Serotyping
6.2 Enrichment culture: Mix the food sample with the modified phosphate buffer enrichment solution at a ratio of 1:10 and place it in a 4℃ refrigerator for cold enrichment.
6.3 Alkali treatment: Mix 0.5mL of the cold enrichment solution of meat and its products with 4.5mL of the alkaline treatment solution for 15s. 6.4 Separation culture: Inoculate the cold enrichment solution and the alkaline-treated cold enrichment solution into CIN-I and modified Y culture medium respectively, and after culturing at 26℃ for 48h, pick the red bull's eye-shaped colonies on CIN-I and the colorless, transparent, non-sticky colonies on modified Y for further identification. 6.5 Modified Klebsiella disaccharide test: Inoculate the above-mentioned suspicious colonies into the modified Klebsiella disaccharide tube, and culture at 26℃ for 24h. Those with yellowing of the slant and bottom will be further identified by biochemical identification.
GB/T4789.8-2003
6.6 Urease test and motility observation Inoculate the suspected culture on the modified Krebs-Saccharide into the urea medium. Pay attention to the large inoculation volume. Pick up the inoculation loop, shake for a few seconds, and place it at 26℃ for 2h~4h. Then inoculate the positive ones into two tubes of semi-solid, place them in 26℃ and 37℃ constant temperature incubators respectively, and culture them for 24h. If there is motility at 26℃, microscopic examination and further biochemical tests can be carried out. 6.7 Staining microscopic examination: Smear stain the above suspected colonies and observe them under a microscope. If they are Gram-negative coccobacilli, sometimes round or rod-shaped, and the size is (0.8μm~3.0μm)×0.8μm, the following biochemical tests will be carried out. 6.8 Biochemical characteristics: Further biochemical tests will be carried out on the above suspected colonies. All biochemical reactions are cultured at 26℃. The main biochemical characteristics of this bacterium and the differences from other species are shown in Table 1. Table 1 Identification list of biochemical characteristics of Yersinia enterocolitica and other similar bacteria
Motility (26℃)
Urease
VP test (26℃)
Ornithine decarboxylase
Raffinose
Sorbitol
Mannitol
Rhamnose
Enterocolitis
Yersinia enterocolitica
Yersinia intermedia
Note: Ten are positive, one is negative, and d has different biochemical types. Yersinia freundii
Yersinia kirschniki
Yersinia pseudotuberculosis
Yersinia pestis
Yersinia spp
6.9 Serological typing: In addition to biochemical identification, serological typing can also be done. At present, 27 types of O-type serological factors can be produced in China for use in various places. The specific operation method is the same as the Salmonella O-factor serological typing. 57
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