GB 4789.26-2023National food safety standard - Food microbiological examination - Commercial sterilization (English PDF)

2.1 Commercial sterility

A state in which food has been moderately heat sterilized and does not contain pathogenic

microorganisms or non-pathogenic microorganisms that can reproduce in it at normal

temperatures.

2.3 Acidic foods

Foods that have not been acidified, and after sterilization, the balanced pH of the food itself or

the soup is equal to or less than 4.6, and the water activity is greater than 0.85.Tomato products

with a pH less than 4.7 are acidic foods.

2.4 Acidified foods

Foods whose water activity is greater than 0.85 and whose balance pH is equal to or less than

4.6 after adding acidity regulators or acidifying the food through other acidification methods.

3.1 Refrigerator. 2 degrees C~5 degrees C;

3.2 Constant temperature incubator. 30 degrees C+/-1 degrees C, 36 degrees C+/-1 degrees C, 55 degrees C+/-1 degrees C;

3.3 Constant temperature culture chamber. 30 degrees C+/-2 degrees C, 36 degrees C+/-2 degrees C, 55 degrees C+/-2 degrees C;

4.1 Culture medium. See Appendix A.

4.2 Crystal violet staining solution. See A.8 in Appendix A.

4.6 Ethanol solution containing 4% iodine. 4g of iodine is dissolved in 100mL of 70% ethanol

solution.

4.7 75% ethanol solution. Measure 75mL of absolute ethanol and 25mL of water respectively,

mix well and set aside.

5.1 Inspection procedures

The commercial sterility inspection procedures in the food circulation field are shown in Figure

1.

5.2.2 Heat preservation

Take 1 sample from each batch and store it in a refrigerator at 2 degrees C~5 degrees C as a control, and keep

the remaining samples at 36 degrees C+/-1 degrees C for 10 d.

5.2.3 Opening food containers

5.2.4 Retention samples

After opening, use a sterile straw or other appropriate tools to take out at least 30mL (g) of the

contents into a sterilized container from a sterile operation; and store it in a refrigerator at 2°C

~ 5°C. It can be used for further testing when necessary. The sample can be discarded after

reaching the test conclusion.

5.2.5 Sensory inspection

In an inspection chamber with sufficient light and clean air and no odor, pour the sample

contents into a white enamel plate or glass container (suitable for liquid samples); and observe

and smell the structure, shape, color, and smell of the product. Samples containing solid matter

shall check the product properties according to the food; identify whether the food has signs of

corrosion and deterioration; and observe the conditions inside the packaging container and

record them.

5.2.6 pH measurement and result analysis

5.2.7 Stained smear microscopy

5.3 Result judgment and report

5.3.1 If the sample does not bulge in the can (bag, bottle, cup, etc.) or leak after the heat

preservation test, open it after heat preservation; and if it is confirmed through sensory

inspection, pH measurement, and smear microscopy that there is no microbial proliferation, the

sample can be reported commercial sterility.

5.3.2 If the sample does not bulge in the can (bag, bottle, cup, etc.) or leak after the heat

preservation test, open it after heat preservation; and if it is confirmed through sensory

inspection, pH measurement, and smear microscopy that there is microbial proliferation, the

sample can be reported non-commercial-sterility.

6.1 Commercial sterility inspection procedures in food production field

See Figure 2 for commercial sterility inspection procedures in the field of food production.

6.2 Inspection procedures

6.2.1 Preparation of sample

After food production and processing, production enterprises shall establish appropriate

sampling plans and AQL (acceptance quality limit) based on product characteristics and

enterprise quality objectives, product sterilization methods, specifications, batch size and other

factors, and with reference to relevant national standards.

6.2.2 Heat preservation

Food production companies can refer to Table 1 to develop a heat preservation plan suitable for

product inspection of this company. The extracted samples should be carried out heat

preservation in a constant-temperature culture chamber or constant-temperature incubator

according to the requirements of the heat preservation plan.

6.2.7 Stained smear microscopy

6.3 Result judgment and report

6.3.1 If the taken sample has not occurred expanded cans (bags, bottles, cups, etc.) or leakage

after the heat preservation test, and if it is confirmed that there is no microbial proliferation

through sensory inspection, pH test, staining microscopy, or inoculation culture, then the

sample shall be reported as commercial sterility;

Appendix A

Culture Media and Reagents

A.1 Bromocresol purple glucose broth

A.2 Cooked meat culture medium

A.2.1 Ingredients

Beef infusion. 1000.0mL;

A.2.2 Preparation method

A.2.2.1 Weigh 500g of fresh ground beef with the fat and fascia removed; add 1000 mL of

distilled water and 25.0 mL of 1 mol/L sodium hydroxide solution; stir and boil for 15 min;

fully cool. Remove surface fat; clarify; filter; and add water to make up to 1000mL, which is

the beef infusion. Add various ingredients in A.2.1 except minced meat residue, and correct the

pH to 7.8+/-0.2.

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