🍎 Determination of total phosphorus in meat and meat products (including poultry) as phosphorus pentoxide — about 5 g of sample is dried and ashed according to ISO 936, the ash is dissolved in 10 ml of 1 + 2 nitric acid on a water bath for 30 min, the solution is made up to 100 ml and filtered, and 20 ml of filtrate with 30 ml of vanadate–molybdate reagent are measured after at least 15 min at 430 nm against a 10–60 µg P2O5/ml curve; result in % (m/m) to three decimal places, PN-ISO 13730 (standard withdrawn in PKN)

Food chemistry PN-ISO 13730

Overview

WHAT THE STANDARD COVERS. We read the text of the standard in the iTeh sample of ISO 13730:1996 (English text, scan): the full text from the title page through the foreword and Clauses 1–12 to Annex A (bibliography). The sample covers the whole standard.

ACCORDING TO THE TEXT OF ISO 13730:1996. The first edition of 15.12.1996 was prepared by ISO/TC 34 “Agricultural food products”, Subcommittee SC 6 “Meat and meat products”; Annex A is informative. Scope (1): a method for the determination of the total phosphorus content of all kinds of meat and meat products, including poultry; the precision data relate only to processed sausages. Reference (2): ISO 936 (determination of ash; under revision at the time of publication). Definition (3): total phosphorus content — the mass of phosphorus pentoxide determined by this procedure, expressed as a percentage of the mass of the test portion. Principle (4): drying of the test portion and incineration of the residue; after cooling, hydrolysis of the ash with nitric acid; filtration and dilution, then formation of a yellow compound with a mixture of ammonium monovanadate and ammonium heptamolybdate; photometric measurement at 430 nm. Reagents (5): analytical grade, distilled or demineralized water; nitric acid 1 + 2 (1 volume of 65 % acid, 1.40 g/ml, with 2 volumes of water); ammonium monovanadate 2.5 g/l (in 500 ml of boiling water, after cooling with 20 ml of nitric acid to 1000 ml); ammonium heptamolybdate 50 g/l (in about 800 ml of water at about 50 °C, to 1000 ml); colour reagent — equal volumes of nitric acid, vanadate solution and molybdate solution, which should turn from pale yellow to completely clear; phosphate stock solution c(P) = 218 mg/l, c(P2O5) = 500 mg/l (958.8 mg of KH2PO4 dried for 3 h at (103 ± 2) °C, to 1000 ml); standard solutions 0.05–0.30 mg P2O5/ml (10–60 ml of stock and 10 ml of acid in 100 ml flasks); blank solution (2 ml of acid and 30 ml of colour reagent in 100 ml). Apparatus (6): all glassware is cleaned with a phosphate-free detergent and rinsed with water; homogenizing equipment — high-speed rotational cutter or mincer with a plate with holes not exceeding 4.5 mm; water bath at 100 °C; phosphate-free fluted filter paper 15 cm; spectrometer or photoelectric colorimeter with an interference filter at (430 ± 2) nm; 10 mm glass cells; balance accurate to ± 0.001 g; volumetric flasks 100 and 1000 ml; muffle furnace (incineration details in ISO 936). Sampling (7): not part of the method — a recommended method is in ISO 3100-1; a representative sample of at least 200 g, stored without deterioration or change in composition. Preparation (8): homogenization without the temperature rising above 25 °C, with a mincer at least two passes; airtight container; analysis as soon as practicable, always within 24 h of homogenization. Procedure (9): according to a note, two single determinations are carried out to check repeatability; test portion about 5 g weighed to 0.001 g; mineralization in the furnace according to ISO 936; ash with 10 ml of nitric acid, covered with a watch glass for 30 min on a boiling water bath, after cooling quantitatively into a 100 ml flask, made up, filtered rejecting the first 5–10 ml; 20 ml of clear, colourless filtrate and 30 ml of colour reagent into a 100 ml flask, made up, at least 15 min; absorbance at (430 ± 2) nm in a glass cell against the blank. Calibration graph (9.3): 20 ml of each standard solution with 30 ml of reagent to 100 ml — 10, 20, 30, 40, 50 and 60 µg P2O5/ml, at least 15 min, measurement; blank-corrected absorbances against concentrations, best-fitting straight line through the points and the origin; a new graph is prepared for each series of analyses. Calculation (10): total phosphorus as P2O5 in % by mass = c / (20 m), where c is the P2O5 concentration in µg/ml read from the graph and m the test portion mass in g; result to three decimal places. Precision (11): interlaboratory test according to ISO 5725 with processed sausages only; the difference between two results under repeatability conditions should not exceed 0.0070 % (m/m), under reproducibility conditions 0.0117 % (m/m). Test report (12): sampling method (if known), method used, result and — when repeatability was checked — the final result, details not specified or optional, incidents that may have influenced the result, complete identification of the sample. Bibliography (Annex A): ISO 3100-1:1991, ISO 5725:1986 and two German methods (delicatessen industry 1978 and official method 06.00-9 under § 35 LMGB 1992).

STATUS (as of 03.10.2026). In the PKN search (query “PN-ISO 13730”, 03.10.2026) PN-ISO 13730:1999 (Polish version, “Wprowadza: ISO 13730:1996 [IDT]”) carries the note “Wycofana” (withdrawn); the standard’s card gives publication date 24.08.1999, withdrawal date 25.09.2020, KT 93 Meat, Eggs and their Products, and the amendment PN-ISO 13730:1999/Ap1:2004 — “WYCOFANA”; the card does not name a replacing standard. The other search results (PN-S-13730:1965 on hydrometers, PN-ENV 13730-2:2003 on health informatics) concern other fields. In the iTeh catalogue (read on 03.10.2026) ISO 13730:1996 has the status “Withdrawn”, stage 95.99 (withdrawal of International Standard), and the card names ISO 23776:2021 “Meat and meat products — Determination of total phosphorous content” as the document that revised it.

HOW MANY LABORATORIES AND IN WHAT FORM (copy of the accreditation scope database, load up to 17.09.2026, read on 03.10.2026). The number 13730 appears in 5 records at 4 laboratories: AB 381, AB 400 (2), AB 545, AB 601. In the current PCA documents (read on 03.10.2026, issues from 31.10.2025 to 07.08.2026) the number appears in 5 rows — 2 at AB 400 and one at each of the others; in each of the four documents the number of page markers equals the number of PDF pages, without repetitions; a search of all 1291 PCA documents downloaded from BIP on 03.10.2026 found no laboratories outside the database copy (17 laboratories in the register have no link to a scope document on BIP). Form “PN-ISO 13730:1999+Ap1:2004” (AB 381, AB 601; AB 400 with the note “z wył. pkt 8” — excluding clause 8 — and with instruction I-01/PN-ISO 13730:1999 edition 1 of 02.01.2019) and “PN-ISO 13730:1999” (AB 545). None of these items is suspended. The “Laboratories” tab (query “PN-ISO 13730”) shows all 4 laboratories — checked with a tab query on the labcoda.pl production server on 03.10.2026.

WHAT THE LABORATORIES TEST (items in PCA). Test object: meat and meat products (AB 381, AB 545, AB 601); ready meals, fish and fish products, food concentrates, food additives, food supplements, dried and fresh fruit, vegetables and vegetable products, milk and dairy products, confectionery products and semi-finished goods, cereals and cereal products (AB 400). Characteristic: phosphorus content (as P2O5) (AB 545), total phosphorus as P2O5 (AB 381), total phosphorus and — calculated — added phosphorus (AB 400, AB 601). Ranges: (0.019–1.500) % (AB 545), (1.000–15) g/kg (AB 381), (0.020–1.00) % P2O5 (AB 400), (0.2–2.0) g/100 g as P2O5 (AB 601). Technique: spectrophotometric method at all.

WHERE A SEEMINGLY CORRECT RESULT IS EASY TO GET. At the status: the standard and its amendment have been withdrawn in PKN since 25.09.2020, and ISO 13730:1996 has been withdrawn in ISO; laboratories still cite it. At the matrix: the scope is meat and meat products including poultry, and the precision data concern sausages only (1, 11) — AB 400 applies it to fish, milk, cereals, fruit and supplements, excluding clause 8 (preparation of the test sample). At the sample: homogenization at not more than 25 °C and analysis within 24 h (8). At glassware: washing with phosphate-free detergent, phosphate-free filters (6). At colour: the filtrate must be clear and colourless, and the measurement at least 15 min after adding the reagent, against the blank (9.2.4, 9.2.5). At calibration: a new graph for each series (9.3.3). At the result: P2O5, not P — in % (m/m) to three decimal places (3, 10); results in g/kg or g/100 g (AB 381, AB 601) are the same quantity in another unit.

WHAT WE DO NOT GIVE. We did not check the content of ISO 23776:2021 or whether it has been adopted as a Polish Standard. We do not give permitted phosphorus or phosphate contents in meat.

Method principle

About 5 g of homogenized sample is dried and ashed in a muffle furnace (ISO 936), the ash is hydrolysed with 10 ml of 1 + 2 nitric acid for 30 min on a boiling water bath, and the solution is made up to 100 ml and filtered. 20 ml of filtrate with 30 ml of vanadate–molybdate reagent forms a yellow complex whose absorbance is measured after at least 15 min at 430 nm against the blank and a 10–60 µg P2O5/ml curve. Total phosphorus as P2O5 in % by mass = c / (20 m).

Applications

• Total phosphorus in all kinds of meat and meat products, including poultry (1)
• Basis for calculating added phosphorus — as at AB 400 and AB 601 in PCA
• Meat and meat products, and at AB 400 also fish, milk, cereals, fruit, vegetables, supplements and ready meals — items in the accreditation scopes of 4 laboratories in PCA

Key parameters

Standard

Standard number

PN-ISO 13730:1999

Title (PL)

Mięso i przetwory mięsne — Oznaczanie zawartości fosforu całkowitego — Metoda spektrofotometryczna

Title (EN)

Meat and meat products — Determination of total phosphorus content — Spectrometric method

Step-by-step procedure

1. Sample

   ≥ 200 g, homogenization ≤ 25 °C, analysis within 24 h (7, 8). PN-ISO 13730:1999 withdrawn in PKN on 25.09.2020 (03.10.2026).

2. Ashing

   About 5 g (± 0.001 g), mineralization in the furnace according to ISO 936 (9.1, 9.2.1).

3. Hydrolysis

   10 ml HNO3 1 + 2, 30 min on a boiling water bath, to 100 ml, filtration (9.2.2, 9.2.3).

4. Colour and measurement

   20 ml filtrate + 30 ml reagent, ≥ 15 min, 430 nm against the blank (9.2.4, 9.2.5).

5. Result

   From the 10–60 µg/ml curve: P2O5 % = c / (20 m), three decimal places (9.3, 10).

Required equipment and apparatus

Reagents, media and consumables

Health and safety (OHS)

• Nitric acid — work in a fume hood, eye and hand protection
• Muffle furnace and boiling water bath — hot vessels

Frequently asked questions