SN/T 3390-2012Rules for the inspection of composite laminated self-supporting bag for food packaging of plastics materials and aluminum foil (English PDF)

1 Scope

This document describes the qualitative test method for Escherichia coli in cosmetics.

This document is applicable to the test of Escherichia coli in cosmetics.

2 Normative references

The contents of the following documents constitute essential clauses of this document through normative references in the text. Among them, for dated references, only the version corresponding to the date applies to this document; for undated references, the latest version (including all amendments) applies to this document.

SN/T 5075 Specification for sample preparation for microbiological inspection of cosmetics

3 Terms and definitions

There are no terms and definitions that need to be defined in this document.

4 Method summary

This method uses the activity of beta-glucuronidase in Escherichia coli, which can decompose 5-bromo-4-chloro-3-indole-beta-D-glucuronide and form blue-green colonies on trypsin bile salt X-glucuronide agar plates, for qualitative testing.

Note: This method is not applicable to a small number of beta-glucuronidase-negative Escherichia coli, such as O157.

5 Equipment and materials

In addition to the conventional sterilization and culture equipment of the microbiology laboratory, other equipment and materials are as follows.

5.1 Constant temperature incubator: 36 °C ± 1 °C.

5.2 Constant temperature device: 48 °C ± 2 °C.

5.3 Refrigerator: 2 °C ~ 8 °C.

5.4 Homogenizer or emulsion disperser (speed above 1000 r/min).

5.5 Electronic balance: Sensitivity 0.1 g.

5.6 Sterile conical flask: 250 mL or 300 mL.

5.7 Sterile pipette: 10 mL (with 0.1 mL scale).

5.8 Sterile culture dish: Diameter 90 mm.

5.9 Sterile homogenizing bag or homogenizing cup.

5.10 Sterile inoculation loop: 10 µL (about 3 mm in diameter).

5.11 pH meter or precision pH test paper.

6 Culture medium and reagents

7 Inspection procedure