Foodstuffs, Cosmetics and Disinfectants Act, 1972 (Act No. 54 of 1972)RegulationsRegulations - Preservatives and AntioxidantsAnnexure 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.