GB/T 41711-2022 in English

《GB/T 41711-2022食品金属容器内壁涂覆层抗酸性、抗硫性、抗盐性的测定》由TC64（全国食品工业标准化技术委员会）归口，TC64SC2（全国食品工业标准化技术委员会罐头分会）执行，主管部门为国家标准化管理委员会。

Forword
This document is drafted in accordance with GB/T1.1-2020 Guidelines for Standardization Part 1: Structure and Drafting Rules of Standardization Documents.
Please note that some of the contents of this document may involve patents. The issuing agency of this document does not assume the responsibility of identifying the patent. This document is proposed and under the centralized management of the National Technical Committee for Food Industry Standardization (SAC/TC 64).
1 Scope
This document describes the determination method of the acid resistance, sulfur resistance and salt resistance of the inner wall coating and film covering of food metal containers.
This document is applicable to metal containers for food (canned food, beverage and other food) with coated iron (or aluminum) or coated iron (or aluminum) as the base material.
2 Normative References
The contents in the following documents, through normative references, constitute indispensable provisions of this document. Where, for dated references, only the version corresponding to that date applies to this document; For undated references, the latest version (including all amendments) is applicable to this document.
GB/T6682 Specification and Test Methods of Water for Analytical Laboratory
3 Terms and definitions
There are no terms and definitions to be defined in this document.
4 Principle
The acid resistance, sulfur resistance and salt resistance of food metal containers are evaluated by simulating the corrosion of actual contact contents on the inner wall coating and coating of food metal containers.
5 Reagents and materials
Unless otherwise specified, only analytically pure reagents shall be used.
5.1 Reagents
5.1.1 Water, GB/T6682, Grade III.
5.1.2 Glacial acetic acid.
5.1.3 Citric acid monohydrate: purity ≥ 99%.
5.1.4 L-cysteine monohydrate hydrochloride; Purity ≥ 99%.
5.1.5 Potassium dihydrogen phosphate: purity>99%.
5.1.6 Disodium hydrogen phosphate dodecahydrate; Purity ≥ 99%.
5.1.7 Sodium sulfide dihydrate; Purity ≥ 99%.
5.1.8 Sodium chloride: purity>99%.
5.2 Reagent preparation
5.2.1 Acetic acid solution (3% by volume)
Measure 30 ml of glacial acetic acid in a 1000 mL volumetric flask and dilute to volume with water.
5.2.2 Citric acid solution (20 g/L)
6 Instruments and equipment
6.1 High pressure sterilizer: maximum working temperature ≥ 135 ℃, pressure ≥ 0.3 MPa, working time ≥ 24 h.
6.2 Inert container: containers made of stainless steel, polytetrafluoroethylene or glass can be covered and sealed.
6.3 Oven: maximum temperature>≥ 100 ℃, accuracy 0.1 ℃.
7 Test procedures
7.1 Acid resistance
7.1.1 The number of test samples shall not be less than 6.
7.1.2 The acid resistance of metal containers shall be tested with citric acid solution (5.2.2), and the metal containers used to tank the contents containing acetic acid shall be tested with acetic acid solution (5.2.1).
7.1.3 Add acetic acid solution (5.2.1) or citric acid solution (5.2.2) into the metal container until the liquid level is 5 mm~7 mm away from the tank mouth and seal it; Place the metal cap in an inert container (avoid using iron containers for aluminum caps), add test acetic acid solution (5.2.1) or citric acid solution (5.2.2) until the liquid level is 5 mm~7 mm from the mouth of the inert container and seal it.
7.1.4 Place the test metal container or inert container in the autoclave for high-temperature sterilization. The actual sterilization temperature and time are used as the test conditions. If the actual sterilization conditions cannot be obtained, the test temperature shall be selected according to Table I and the test time shall be selected according to Table 2. After the test, take out the sample to be tested after the autoclave naturally depressurizes. Rinse with clean water for several times, dry in an oven at 70 ℃~80 ℃, and then visually inspect the coating on the inner wall for bubbles, peeling, discoloration, whitening, corrosion spots, etc.
7.2 Sulfur resistance
7.2.1 The number of test samples shall not be less than 6.
7.2.2 Mixed solution (5.2.3) shall be used to test the sulfur resistance of iron metal containers, and sodium sulfide solution (5.2.4) shall be used to test the sulfur resistance of aluminum metal containers.
7.2.3 Add the mixed solution (5.2.3) or sodium sulfide solution (5.2.4) into the metal container until the liquid level is 5 mm~7 mm from the tank opening and seal it; Place the metal cap in an inert container (avoid using iron containers for aluminum caps), add mixed solution (5.2.3) or sodium sulfide solution (5.2.4) until the liquid level is 5 mm~7 mm from the mouth and seal.
7.2.4 Place the test metal container or inert container in the autoclave for high-temperature sterilization. The actual sterilization temperature and time are used as the test conditions. If the actual sterilization conditions cannot be obtained, the test temperature shall be selected according to Table 1 and the test time shall be selected according to Table 2. Take out the sample to be tested after the autoclave naturally depressurizes. Rinse with clean water for several times, dry in an oven at 70 ℃~80 ℃, and then visually inspect whether the coating on the inner wall has sulfide corrosion, peeling, discoloration, whitening, etc.
7.3 Salt resistance
7.3.1 The number of test samples shall not be less than 6.
7.3.2 Add sodium chloride solution (5.2.5) into the metal container until the liquid level is 5 mm~7 mm away from the container opening and seal it; Place the metal cap in an inert container (avoid using iron containers for aluminum caps), add sodium chloride solution (5.2.5) until the liquid level is 5 mm~7 mm from the mouth and seal it.
7.3.3 Place the test metal container or inert container in the autoclave for high-temperature sterilization. The actual sterilization temperature and time are used as the test conditions. If the actual sterilization conditions cannot be obtained, the test temperature shall be selected according to Table 1 and the test time shall be selected according to Table 2. Take out the sample to be tested after the autoclave naturally depressurizes. Rinse with clean water for several times, dry in an oven at 70 ℃~80 ℃, and then visually inspect whether the coating on the inner wall is white, peeling, peeling, bubbling, dense corrosion spots, etc.
8 Expression of results
The test report includes the following information:
a) Number of this document;
b) Complete description of the test sample, especially the base material, film thickness, coating type and coating method;
c) Test date;
D Environmental status of the test;
e) Test conditions;
F Reagents used;
g) Test results;
h) Any difference from the specified test procedure.

Forword
1 Scope
2 Normative References
3 Terms and definitions
4 Principle
5 Reagents and materials
6 Instruments and equipment
7 Test procedures
8 Expression of results