GB/T 24691-2009Cleaning agent for fruit and vegetable (English PDF)

4.4 Determination of pH value

It is carried out in accordance with the provisions of GB/T 6368.

4.5 Determination of methanol content (for liquid products)

After preparing the standard solution, according to the provisions of Appendix

D of GB 9985-2000, carry out the determination.

4.6 Determination of formaldehyde content (for liquid products)

It is carried out in accordance with the provisions of Appendix E of GB 9985-

2000.

4.7 Determination of arsenic content

It is carried out in accordance with the provisions of Appendix F of GB 9985-

2000.

4.8 Determination of heavy metal content

It is carried out in accordance with the provisions of Appendix G of GB 9985-

2000.

4.9 Determination of fluorescent brightener

It is carried out in accordance with the provisions of Appendix C of GB 9985-

2000.

4.10 Microbiological examination

For the total number of bacteria AND the coliform group, they are respectively examined, in accordance with GB/T 4789.2 and GB/T 4789.3.

4.11 Determination of the biodegradability of surfactants

For the biodegradability of the surfactant, which is used in the product formulation of the cleaning agent for fruit and vegetable, it shall be carried out in accordance with the provisions of GB/T 15818.

4.12 Determination of net content

For the inspection, sampling method and determination rules of the net content of the sales package of cleaning agent for fruit and vegetable, they shall be carried out in accordance with the provisions of JJF 1070.

Appendix A (Normative)

Verification method of cleaning agent for fruit and vegetable on the removal of residual pesticides

A.1 Scope

This method specifies the preparation methods of pesticide emulsions AND samples containing pesticides on the surface of vegetables; the cleaning methods of samples, which contain pesticides on the surfaces of vegetables;

the determination method of pesticide removal rate.

This method is suitable for the determination of the removal rate of cypermethrin and propoxur pesticides, by a cleaning agent for fruit and vegetable, which is compounded with surfactants and additives.

The detection range of this method is 4.3 µg/mL ~ 430.0 µg/mL for cypermethrin,

1.5 µg/mL ~ 150.0 µg/mL for propoxur.

A.2 Normative references

GB/T 13174 Determination of detergency and cycle of washing property for laundry detergents.

A.3 Principles of the method

Prepare vegetable samples with pesticides several times exceeding the limit.

Simulate actual washing conditions. After cleaning with a 0.2% cleaning agent for fruit and vegetable solution, use the extraction and concentration method to obtain the residual pesticides. Use high performance liquid chromatography, to determine the amount of pesticide residues, on the surface of the vegetables before and after cleaning. Calculate the removal rate of residual pesticides.

Compare it with the removal rate of the residual pesticides, after washing by the water of certain hardness. The ratio is the evaluation result of the cleaning effect of the cleaning agent for fruit and vegetable, on the residual pesticides.

A.4 Reagents

Unless otherwise specified, it only uses the confirmed analytical reagents AND distilled or deionized water or water of equivalent purity, in the analysis (applicable to all appendixes of this standard).

A.4.1 Anhydrous ethanol;

Weigh 5.00 g of cypermethrin and 2.50 g of propoxur. Dissolve it in 500 g of absolute ethanol solution. After stirring evenly, use 250 mg/kg of hard water to make its mass reach to 5000 g. Mix well. Prepare for use. The concentration of the pesticide emulsion is. 0.1% cypermethrin and 0.05% propoxur.

A.6.3 Preparation of vegetables containing pesticides

Completely immerse the sweet beans in the pesticide emulsion for 20 minutes.

Take them out. Shake off the residual liquid droplets from the surface. Place them in a cool place, at room temperature, for 24 hours. Divide the prepared vegetable samples into 3 groups. one group is unwashed (the amount of pesticides on the surface of unwashed vegetable samples is preferably 140 mg/kg ~ 200 mg/kg); one group is washed by water; one group is washed by the cleaning agents for fruit and vegetable. Each group contains 2 sets, each set is 80 g. Prepare for use.

A.7 Cleaning method

A.7.1 Water washing method

The washing temperature is 30 °C; the hard water is 800 mL (A.4.11).

Washing. Take 800 mL of hard water (A.4.11). Add it to the fruit and vegetable dehydrator. At the same time, add one set of the prepared vegetables (A.6.3).

Soak it for 1 min. Then start washing at a uniform speed, for 4 min. The washing and stirring method are one clockwise round plus one counterclockwise round, at a frequency of about 19 r/min ~ 21 r/min.

Rinsing. Put the washed vegetable samples into the inner cylinder of a clean fruit and vegetable dehydrator. First use 1000 mL of hard water (A.4.11) to rinse it completely. Discard it. Then add 1000 mL of hard water (A.4.11). Use the washing and stirring method, which is same as the above method, to wash it for 30 s (one clockwise round plus one counterclockwise round, at the frequency of about 19 r/min ~ 21 r/min). Discard the second rinsing water. Use the same method to carry out the third rinsing.

Conduct parallel tests, at the same time.

A.7.2 Washing method of cleaning agent for fruit and vegetable

Use hard water (A.4.11) to prepare the cleaning agent for fruit and vegetable solution, which has a concentration of 0.2%, at the washing temperature of

30 °C.

Washing. Add 800 mL of cleaning agent solution for fruit and vegetable, which has a concentration of 0.2%. Put in one set of the prepared vegetables (A.6.3) at the same time. Immerse it for 1 min. Start washing, at a constant speed, for

Appendix B (Normative)

Qualitative determination of residues of cleaning agents for fruit and vegetable

B.1 Principles of the method

Use the amount of final rinsing water, which is carried on the surface of a certain amount of vegetable, as the amount of removal when determining the residual amount of cleaning agent for fruit and vegetable. Use the anionic surfactant as a representative residue, to determine the anionic surfactant, which is remained in the rinsing solution. This anionic surfactant reacts with the cationic dye, in the acid mixed indicator, to form a salt which is dissolved in chloroform. This salt makes the chloroform layer appear to be pink, which is from light to deep, as determined by the content of anionic surfactants.

B.2 Reagents

B.2.1 Standard solution of sodium lauryl sulfate, c = 2 mg/kg

Weigh 0.1 g (accurate to 0.001 g) of sodium lauryl sulfate (content is based on

100%). Use water to dissolve it. Make its volume reach to 100 mL. Use a pipette to transfer 2.0 mL of the above solution, into a 1000 mL volumetric flask. Use water to dissolve it. Mix it uniformly to prepare for use.

B.2.2 Acid mixed indicator

It is prepared according to the requirements of 4.8 in GB/T 5173-1995.

B.2.3 250 mg/kg standard hard water

It is prepared according to the requirements of 7.1 in GB/T 13174-2008.

B.2.4 Trichloromethane

B.3 Instruments

B.3.1 Glass measuring cylinder with stopper, 100 mL;

B.3.2 Pipettes, 2 mL, 10 mL, 50 mL;

B.3.3 Volumetric flask, 1000 mL;

B.3.4 Stainless steel tweezers.

Appendix C (Normative)

Determination of anionic surfactants - Methylene blue method (Quantitative determination of residues of cleaning agent for fruit and vegetable)

C.1 Method summary

For the complex, which is formed by the anionic surfactant and methylene blue, it is extracted by chloroform. Then the content of the anionic surfactant is determined by spectrophotometry.

C.2 Scope of application

This method is suitable for anionic surfactants, which contain sulfonic acid group and sulfuric acid group.

C.3 Reagents

C.3.1 Standard solution of anionic surfactant

Take 1 g (accurate to 0.001 g) of the reference substance, which is equivalent to 100% (purity is determined in accordance with GB/T 5173). Use water to dissolve it. Make its volume reach to 1000 mL. Mix it uniformly. The concentration of anionic surfactant in this solution is 1 g/L. Pipette 10.0 mL of this solution. In a 1000 mL volumetric flask, add water to the mark. Mix uniformly.

Then the concentration of the anionic surfactant in this use solution is 0.01 mg/mL.

C.3.2 Sulfuric acid;

C.3.3 Sodium dihydrogen phosphate washing solution

Dissolve 50 g of sodium dihydrogen phosphate in water. Add 6.8 mL of sulfuric acid (C.3.2). Make its volume reach to 1000 mL.

C.3.4 Methylene blue solution

Weigh 0.1 g of methylene blue. Use water to dissolve it. Dilute it to 100 mL.

Pipette 30 mL of this solution. Use sodium dihydrogen phosphate washing solution (C.3.3) to dilute it 1000 mL.

C.3.5 Chloroform.

C.4 Instruments

Appendix D (Normative)

Determination of ethoxy-type surfactants - Cobalt thiocyanate method (Quantitative determination of residues of cleaning agent for fruit and vegetable)

D.1 Method summary

For the complex, which is formed by the ethoxy-type surfactant and cobalt thiocyanate, it is extracted by chloroform; then the surfactant content is measured by spectrophotometry.

D.2 Scope of application

This method is suitable for the surfactants, which have a polyoxyethylene type single-chained EO adduct number of 3 ~ 40, or double-chained, triple-chained, four-chained EO adduct number of 6 ~ 60, as well as the polyethylene glycol (molar mass 300 ~ 1000), polyether, etc.

D.3 Reagents

D.3.1 Standard solution of ethoxylated surfactant

Weigh 1 g (accurate to 0.001 g) of the reference substance, which is equivalent to 100% (purity determined according to Chapter 8 of GB/T 13173-2008). Use water to dissolve it. Transfer and make its volume reach to 1000 mL. Mix well.

The surfactant concentration of this solution is 1 g/L. Pipette 25.0 mL of this solution, into a 250 mL volumetric flask. Add water to make the volume reach to the mark. Mix well. Then the concentration of the surfactant of this use solution is 0.1 mg/L.

D.3.2 Ammonium thiocyanate;

D.3.3 Cobalt nitrate (hexahydrate);

D.3.4 Benzene;

D.3.5 Cobalt ammonium thiocyanate solution

Dissolve 620 g of ammonium thiocyanate (D.3.2) AND 280 g of cobalt nitrate (D.3.3), in a small amount of water. Mix well. Make its volume reach to 1000 mL. Then, respectively use 30 mL of benzene to extract it twice. Prepare for use.

Appendix E (Normative)

Determination of zwitterionic surfactants -- Gold orange - method 2 (Quantitative determination of residues of cleaning agent for fruit and vegetable)

E.1 Method summary

For the complex, which is formed by zwitterionic surfactant and golden orange-

2, under the buffer condition of pH = 1, it is extracted by chloroform; then the content of zwitterionic surfactant is determined by spectrophotometry.

E.2 Scope of application

This method is applicable to zwitterionic surfactants, as well as cationic surfactants and mixtures of the two.

E.3 Reagents

E.3.1 Standard solution of fatty alkyl dimethyl betaine

Accurately weigh 1.0 g (accurate to 0.001 g) of the fatty alkyl dimethyl betaine, which is equivalent to 100% (purity is determined according to QB/T 2344). Use water to dissolve it. Transfer and make its volume reach to 1000 mL. Mix well.

The surfactant concentration of this solution is 1 g/L. Pipette 10.0 mL of this solution in a 1000 mL volumetric flask. Add water to make its volume reach to the mark. Mix well. Then the concentration of the surfactant in this use solution is 0.01 mg/mL.

E.3.2 Golden orange-2

Weigh 0.1 g of Golden orange-2.Dissolve it in 100 mL of water. Mix well.

E.3.3 Hydrochloric acid

0.2 mol/L hydrochloric acid solution.

E.3.4 Potassium chloride

0.2 mol/L potassium chloride solution.

E.3.5 Buffer solution, pH = 1

Measure 97 mL of 0.2 mol/L hydrochloric acid solution (E.3.3), 53 mL of 0.2 mol/L potassium chloride solution (E.3.4). Add 50 mL of water. Shake well for

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