3091 NTERNATIONAL STANDARD (TSO INTERNATIONAL ORGANIZATION FOR STANDARDIZATION MEKIYHAPOIHA OPIAHM3ALMY HO CTAHIAPTH3ALWI.ORGANISATION INTERNATIONALE DE NORMALISATION Meat and meat products -- Determination of nitrate content (Reference method) Viandes et produits a base de viande -- Détermination de la teneur en nitrates (Méthode de reférence) First edition - 1975-09-01 Ref. No. 1S0 3091-1975 (E) ISO 3091-1975 (E) UDC 637.5 : 546.175 Descriptors : meat, meat products, chemical analysis, determination of content, nitrates. Price based on 5 pages without license from IHS Not for Resale FOREWORD Iso (the International Organization for Standardization) is a worldwide federation of national standards institutes (IsO Member Bodies). The work of developing International Standards is carried out through ISO Technical Committees. Every Member Body interested in a subject for which a Technical Committee has been set up has the right to be represented on that Committee. International organizations, governmental and non-governmental, in liaison with IsO, also take part in the work. Draft International Standards adopted by the Technical Committees are circulated to the Member Bodies for approval before their acceptance as International Standards by the ISO Council. International ISO/TC 34, Agricultural food products, and circulated to the Member Bodies in May 1974. It has been approved by the Member Bodies of the following countries : Australia Germany South Africa, Rep. of Austria Hungary Spain Bulgaria India Thailand Ireland Turkey Czechoslovakia Denmark Israel United Kingdom Egypt, Arab Rep. of U.S.S.R. Netherlands Ethiopia Poland Yugoslavia France Romania The Member Body of the following country expressed disapproval of the document on technical grounds : Canada International Organization for Standardization, 1975 Printed in Switzerland without licensefrom IHS Not for Resale ISO 3091-1975 (E) INTERNATIONAL STANDARD Meat and meat products -- Determination of nitrate content (Reference method) 1 SCOPE AND FIELD OF APPLICATION 5.2.2 Reagent I! This International Standard specifies a reference method Dissolve 220 g of zinc acetate dihydrate for the determination of the nitrate content of meat and [Zn(CH3CO0)2.2H2O] and 30 ml of glacial acetic acid in meat products. water and dilute to 1 000 ml. 5.2.3 Borax solution, saturated 2 REFERENCES Dissolve 50 g of disodium tetraborate decahydrate ISO 2918, Meat and meat products Determination of (Na2B407.10H20) in 1 000 ml of tepid water and cool to nitrite content (Reference method). room temperature. Is0 3100, Meat and meat products- Sampling 5.3 Cadmium sulphate solution, 30 g/l. Dissolve 37 g of cadmium sulphate (3CdS04-8H20) in 3 DEFINITION water and dilute to 1 000 ml. nitrate content of meat and meat products : The nitrate content determined accordingto the procedure described in 5.4 Hydrochloric acid solution, about 0,1 N. this International Standard and expressed as milligrams of potassium nitrate per kilogram (parts per million). Dilute 8 ml of concentrated hydrochloric acid solution (p20 1,19 g/ml) to 1 000 ml with water. 4 PRINCIPLE 5.5 Ammonia buffer solution, pH 9,6 to 9,7. Extraction of a test portion with hot water, precipitation of the proteins and filtration. Dilute 20 ml of concentrated hydrochloric acid (p20 1,19 g/ml) with 500 ml of water. After mixing, add Reduction of the extracted nitrates to nitrite by metallic 10 g of ethylenediamine tetra-acetic acid disodium-salt cadmium. Development of a red colour by addition of [CH2 N(CH2COOH)CH2COONal2·2H2O, and dihydrate, sulphanilamide and N-1-naphthylethylenediamine dihydro- 55 ml of concentrated ammonia (p2o 0,88 g/mi). Dilute to chloride to the filtrate and photometric measurement at 1 000 ml with water and mix. Check the pH. a wavelength of 538 nm. 5.6 Sodium nitrite standard solutions. 5 REAGENTS Dissolve 1,000 g of sodium nitrite (NaNO2) in water and dilute to 100 ml in a one-mark volumetric flask. Pipette All reagents sha