Regulations > Regulations - Preservatives and Antioxidants > Annexure C : Specific Criteria of Purity of Preservatives

ANNEXURE C

SPECIFIC CRITERIA OF PURITY OF PRESERVATIVES

GENERAL OBSERVATIONS

(a)	Save as otherwise stated, quantities and percentages are calculated by mass on the anhydrous substance.

(b)	Where the relevant substance is initially not anhydrous and "volatile substances" are involved, water is included among these substances.

(c)	Where the drying period is not specified, this means "dried to constant mass".

BENZOIC ACID

Appearance	White crystalline powder.
Melting range	121,5 - 123,5°C, after vacuum drying in a sulphuric acid desiccator.
Content	Not less than 99,5 per cent.
Sulphated ash	Not more than 0,05 per cent.
Polycyclic acids	On fractional acidification of a neutralised solution of benzoic acid, the first precipitate shall not have a different melting point from that of benzoic acid.
Organic chlorine	Not more than 0,07 per cent corresponding to 0,3 per cent expressed as monochlorobenzoic acid.
Readily oxidisable substances	Pink colour maintained with not more than 0,5 ml of KMnO4 (0,1N) per g in sulphuric acid solution (0,1N) after one hour, at room temperature.
Sulphuric acid test	A cold solution of 0,5g of benzoic acid in 5 ml of 94,5 - 95,5 per cent sulphuric acid should not show a stronger colouring than that of a reference liquid containing 0,2 ml of cobalt chloride TSC*, 0,3 ml of ferric chloride TSC , 0,1 ml of copper sulphate TSCA and 4,4 ml of water.

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*Cobalt chloride TSC: Dissolve approximately 65 g of cobalt chloride CoC12 6H2O in a sufficient quantity of a mixture of 25 ml hydrochloric acid and 975 ml of water to give a total volume of 1Ρ. Place exactly 5 ml of this solution in a 250 ml round bottomed iodine flask, add 5 ml of 3 per cent hydrogen peroxide, then 15 ml of a 20 per cent solution of sodium hydroxide. Boil for 10 minutes, allow to cool, add 2 g of potassium iodide and 20 ml of 25 per cent sulphuric acid. After the precipitate is completely dissolved, titrate the liberated iodine with sodium thiosulphate (0,1N) in the presence of starch T S.§ 1 ml of sodium thiosulphate (0,1N) corresponds to 23,80 mg of CoC12 6H2O. Adjust final volume of solution by the addition of a sufficient quantity of the hydrochloric acid/water mixture to give a solution containing 59,5 mg of CoC12 6H20 per ml.

Ferric chloride TSC : Dissolve approximately 55 g of ferric chloride in a sufficient quantity of a mixture of 25 ml of hydrochloric acid and 975 ml of water to give a total volume of 1Ρ. Place 10 ml of this solution in a 250 ml round-bottomed iodine flask, add 15 ml of water and 3 g of potassium iodide: leave the mixture to stand for 15 minutes. Dilute with 100 ml of water then titrate the liberated iodine with sodium thiosulphate (0, 1N) in the presence of starch TS. § 1 ml of sodium thiosulphate (0,1N) corresponds to 27,03 mg FeC136H2O. Adjust the final volume of the solution by the addition of a sufficient quantity of the hydrochloric acid/water mixture to give a solution containing 45,0 mg of FeC136H2O per ml.

Α Copper sulphate TSC: Dissolve approximately 65 g of copper sulphate CuSO45H2O in a sufficient quantity of a mixture of 25 ml of hydrochloric acid and 975 ml of water to give a total volume of 1Ρ. Place 10 ml of this solution in a 250 ml round-bottomed iodine flask, add 40 ml of water, 4 ml of acetic acid and 3 g of potassium iodide. Titrate the liberated iodine with sodium thiosulphate (0,1N) in the presence of starch T S. § 1 ml o f sodium thiosulphate (0,1N) corresponds to 24,97 mg of CuS045H2O. Adjust the final volume of the solution by the addition of a sufficient quantity of the hydrochloric acid water mixture to give a solution containing 62,4 mg of CuSO45H2O per ml.

§Starch TS : Triturate 0,5 g starch (potato, maize or soluble starch) with 5 ml of water; to the resulting paste add a sufficient quantity of water to give a total volume of 100 ml stirring all the time. Boil for a few minutes, allow to cool, filter. The starch solution should be freshly prepared.

CALCIUM BENZOATE

Appearance	White crystalline powder.
Melting range of benzoinc acid isolated by acidification and not recrystallised	121,5 - 123,5°C, after vacuum drying in a sulphuric acid desiccator.
Content	Not less than 99 per cent, after drying at 105°C.
Volatile substances	Not more than 17,5 per cent, determined by drying at 105°C.
Polycyclic acids	On fractional acidification of a neutralised solution of benzoic acid, the first precipitate shall not have a different melting point from that of benzoic acid.
Organic chlorine	Not more than 0 ,06 per cent , corresponding to 0,25 per cent expressed as mono-chlorobenzoic acid .
Readily oxidisable substances	Pink colour maintained with not more than 0,5 ml of KMnO4 (0,1N) per g in sulphuric acid solution (0,1N) after one hour, at room temperature.
Degree of acidity or alkalinity	Neutralisation of 1 g of calcium benzoate in the presence of phenolphthalein shall not require more than 0,25 ml of NaOH (0,1N) or HC1 (0,1N).

CALCIUM METABISULPHITE

Appearance	White powder or yellowish lumps.
Content	Not less than 95 per cent of CaS2O5 and not less than 66 per cent of SO2.
Iron	Not more than 35 m g/kg of Fe.
Selenium	Not more than 10 mg/kg based on the SO2 content.

CALCIUM PROPIONATE

Appearance	White crystalline powder.
Content	Not less than 99 per cent< after drying for two hours at 105°C.
Volatile substances	Not more than 4 per cent, determined by drying for two hours at 105°C.
Water insolubles	Not more than 0,3 per cent.
Readily oxidisable substances	No trace.
Iron	Not more than 30 m g/kg.

CALCIUM SORBATE

Appearance	Fine white crystalline powder showing no change in colour after heating for ninety minutes at 105°C.
Melting range of sorbic acid isolated by acidification and not recrystallised	133 - 135°C, after vacuum drying in a sulphuric acid desiccator.
Content	Not less than 98 per cent, after vacuum drying for four hours in a sulphuric acid desiccator.
Volatile substances	Not more than 2 per cent, determined by vacuum drying in a sulphuric acid desiccator.
Aldehydes	Not more than 0,1 per cent, calculated as formaldehyde.

HEXAMETHYLENE TETRAMINE

Appearance	Colourless or white crystalline powder.
Content	Not less than 99 per cent C4H12N4.
Loss on drying	Not more than 0,5 per cent after drying at 105°C in vacuum over phosphorous pentoxide for two hours.
Sublimation point	Sublimes at at about 260°C.
Sulphated ash	Not more than 0,05 per cent.
Sulphates	Not more than 0,005 per cent, expressed as SO4.
Chlorides	Not more than 0,005 per cent expressed as C1.

LYSOZYME

Appearance	White odourless powder with a somewhat sweet taste.
Solubility	Freely soluble in water; insoluble in common organic solvents.
Specifications:
Nitrogen	16-17 per cent.
Chloride	not more than 0,3 per cent.
Humidity	not more than 4 per cent.
Ash	not more than 0,3 per cent.
Acticity	not less than 22 500 units/mg.
Bacterial count	not more than 100 viable organisms/g.
Heavy metals	not more than 5 mg/kg.
Arsenic	not more than 2 mg/kg.

N-PROPYL P-HYDROXBENSOATE

Appearance	White crystalline powder.
Melting point	95 - 97°C after drying for two hours at 80°C.
Content	Not less than 99,5 per cent, after drying for two hours at 80°C.
Sulphate ash	Not more than 0,05 per cent.
Free acids	Not more than 0,35 percent, expressed as p-hydroxybenzoic acid.

POTASSIUM BENZOATE

Appearance	White crystalline powder.
Melting range of benzoic acid isolated by acidification and not recrystallised	121,5 - 123,5°C, after vacuum drying in a sulphuric acid desiccator.
Content	Not less than 99 per cent, after drying at 105°C.
Volatile substances	Not more than 26,5 per cent, determined by drying at 105°C.
Polycyclic acids	On fractional acidification of a (neutralised) solution of potassium benzoate the first precipitate shall not have a different melting range from that of benzoic acid.
Organic chlorine	Not more than 0,06 per cent, corresponding to 0,25 per cent expressed as mono-chlorobenzoic acid.
Readily oxidisable substances	Pink colour maintained with not more than 0,5ml of KMnO4 (0,1N) per g in sulphuric acid solution (0,1N) after one hour, at room temperature.
Degree of acidity or alkalinity	Neutralisation of 1 g of potassium benzoate in the presence of phenolphthalein shall not require more than 0,25 ml of NaOH (0,1N) or HC1 (0,1N).

POTASSIUM METABISULPHITE

Appearance	Colourless crystals or white crystalline powder.
Content	Not less than 95 per cent of K2S2O5, and not less than 54,7 per cent of SO2.
Iron	Not more than 30 mg/kg of Fe.
Selenium	Not more than 10 mg/kg based on the SO2 content.

POTASSIUM NITRATE

Appearance	White or slightly yellow deliquescent granules.
Content	Not less than 95 per cent after drying for four hours over silica gel.
pH (5 per cent solution in carbon dioxide-free and ammonia-free water).	Not less than 6,0 and not more than 9,0.

POTASSIUM SORBATE

Appearance	White crystalline powder showing no change in colour after heating for 90 minutes at 105°C.
Melting range of sorbic acid isolated by acidification and not recrystallised.	133 - 135°C, after vacuum drying in a sulphuric acid desiccator.
Content	Not less than 99 per cent, after vacuum drying for four hours in a sulphuric acid desiccator.
Volatile substances	Not more than 1 per cent, determined by vacuum drying in a sulphuric acid desiccator.
Aldehydes	Not more than 0,1 per cent, calculated as formaldehyde.

PROPIONIC ACID*

Appearance	Colourless or slightly yellowish liquid.
Content	Not less than 99 per cent.
Non-volatile substances	Not more than 0,05 per cent.
Aldehydes	Not more than 0,1 per cent, expressed as formaldehyde.
Iron	Not more than 30 mg/kg.

SODIUM BENZOATE

Appearance	White crystalline powder.
Melting range of benzoic acid isolated by acidification and not recrystallised	121,5 - 123,5°C, after vacuum drying in a sulphuric acid desiccator.
Content	Not less than 99,5 per cent, after drying for four hours at 105°C.
Volatile substances	Not more than 1 per cent, determined by drying for four hours at 105°C.
Polycyclic acids	On fractional acidification of a (neutralised) solution of sodium benzoate, the first precipitate shall not have a different melting range from that of benzoic acid.
Organic chlorine	Not more than 0,06 per cent, corresponding to 0,25 per cent, expressed as mono-chlorobenzoic acid.
Readily oxidisable substances	Pink colour maintained with not more than 0,5 ml of KMnO4 (0,1N) per g in sulphuric acid solution (0,1N) after one hour, at room temperature.
Degree of acidity of alkalinity	Neutralisation of 1 g of sodium benzoate, in the presence of phenolphthalein, shall not require more than 0,25 ml of NaOH (0,1N) or HC1 (0,1N).

SODIUM METABISULPHITE

Appearance	Colourless crystals or white crystalline powder.
Content	Not less than 95 per cent of Na2S2O5 and not less than 64 per cent of SO2.
Iron	Not more than 35 mg/kg of Fe.
Selenium	Not more than 10 mg/kg, based on the SO2 content.

SODIUM NITRATE

Appearance	White crystalline slightly hygroscopic powder.
Content	Not less than 99 per cent, after drying at 105°C.
Volatile substances	Not more than 1 per cent, determined by drying at 105°C.
Nitrites	Not more than 30 mg/kg, expressed as NaNO2.

SODIUM NITRITE

Appearance	White crystalline powder or yellowish lumps.
Content	Not less than 98 per cent, after vacuum drying in a sulphuric acid desiccator, the remainder shall consist almost entirely of sodium nitrite.
Water	Not more than 1 per cent.

SODIUM N-PROPYL P-HYDROXYBENZOATE

Appearance	White or almost white crystalline hygroscopic powder.
Melting range of ester isolated by acidification and not recrystallised	94 - 97°C, after vacuum drying in a sulphuric acid desiccator.
Content: Propyl ester of p-hydrocybenzoic acid	Not less than 85 per cent, after vacuum drying in a sulphuric acid desiccator.
Volatile substances	Not more than 5 per cent, determined by vacuum drying in a sulphuric acid desiccator.
Sulphated ash	34 per cent to 36 per cent.
pH	pH of 0,1 per cent aqueous solution shall be between 9, 8 and 10,2.
Salicyclic acid	Not more than 0,1 per cent.

SODIUM PROPIONATE

Appearance	White crystalline powder.
Content	Not less than 99 per cent, after drying for two hours at 105°C.
Volatile substances	Not more than 4 per cent, determined by drying for two hours at 105°C.
Water insolubles	Not more than 0,3 per cent.
Readily oxidisable substances	No trace.
Iron	Not more than 30 mg/kg.

SODIUM SORBATE

Appearance	White crystalline powder showing no change after heating for 90 minutes at 105°C.
Melting range of sorbic acid isolated by acidification and not recrystallised.	133 - 135°C, after vacuum drying in a sulphuric acid desiccator.
Content	Not less than 99 per cent, after vacuum drying for four hours in a sulphuric acid desiccator.
Volatile substances	Not more than 1 per cent, determined by vacuum drying in a sulphuric acid desiccator.
Aldehydes	Not more than 0,1 per cent, calculated as formaldehyde.

SODIUM SULPHITE

(anhydrous or heptahydrate)

Appearance	White crystalline powder or colourless crystals.
Content: Anhydrous	Not less than 95 per cent of NaS203 and not less than 48 per cent of SO2.
Heptahydrate	Not less than 48 per cent of NaS2O3 and not less than 24 per cent of SO2.
Thisulphate	Not more than 0,1 per cent of NaS2O3 based on the SO2 content.
Iron	Not more than 50 mg/kg expressed as Fe, based on the SO2 content.
Selenium	Not more than 10 mg/kg, based on the SO2 content.

SORBIC ACID

Appearance	White crystalline powder showing no change in colour after heating for 90 minutes at 105°C.
Melting range	133 - 135°C, after vacuum drying for four hours in a sulphuric acid desiccator.
Content	Not less than 99 per cent, after vacuum drying for four hours in a sulphuric acid desiccator.
Volatile substances	Not more than 3 per cent determined by drying for 24 hours in a sulphuric acid desiccator.
Sulphated ash	Not more than 0,2 per cent.
Aldehydes	Not more than 0,1 per cent calculated as formaldehyde.

SULPHUR DIOXIDE

Appearance	Colourless gas.
Content	Not less than 99 per cent.
Non-volatile substances	Not more than 0,01 per cent.
Sulphur trioxide	Not more than 0,1 per cent.
Other gases not normally present in the air	No trace.
Selenium	Not more than 10 mg/kg.

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* The specification refers to anhydrous propionic acid; for aqueous solutions calculate values corresponding to their propionic acid content.

Foodstuffs, Cosmetics and Disinfectants Act, 1972 (Act No. 54 of 1972)

Regulations

Regulations - Preservatives and Antioxidants

Annexure C : Specific Criteria of Purity of Preservatives