🧂 Determination of chloride content (as sodium chloride) of meat and meat products, including poultry, with a NaCl content of at least 0,25 % (m/m) — dispersion of approx. 50 g of sample in 450 g of water, acidification of 50 ml of the suspension with nitric acid and potentiometric titration with 0,0856 mol/l silver nitrate using a silver electrode to the inflection point of the curve, result to the nearest 0,1 % (m/m), PN-ISO 1841-2

Food chemistry PN-ISO 1841-2

Overview

WHAT THE STANDARD COVERS. Scope from the PKN catalogue card of PN-ISO 1841-2:2002 (Polish version), in full (our translation): “A method is specified for determining the chloride content of meat and meat products, including poultry, with a sodium chloride content equal to or greater than 0,25 percent (m/m). The principle of the method, the reagents used, the apparatus, sampling and preparation of samples, the determination, the calculation of the result and the test report are given. The precision of the method — repeatability and reproducibility — is established. Annex A (informative) gives a bibliography”. We read the text of the standard in the ISO 1841-2:1996 preview IN FULL (Clauses 1–11 and Annex A, four pages of content); the formulae of Clauses 9 and 10 were read from the page image because the text layer of the preview is garbled there.

ACCORDING TO THE TEXT OF ISO 1841-2:1996. The standard was prepared by ISO/TC 34/SC 6 (meat and meat products); Part 1 of the series is the Volhard method (separate entry on PN-ISO 1841-1), Part 2 — the potentiometric method. Scope: chlorides in meat and meat products, including poultry, with a sodium chloride content of at least 0,25 % (m/m). Definition (2.1): total chloride content determined by this method, expressed as sodium chloride in percent by mass. Principle (3): dispersion of a test portion with water, acidification of an aliquot of the suspension and potentiometric titration with silver nitrate solution using a silver electrode. Reagents (4): halogen-free distilled water (test: 1 ml AgNO₃ 0,1 mol/l and 5 ml HNO₃ 4 mol/l in 100 ml of water — not more than slight turbidity); nitric acid 1 + 49 (20 ml of concentrated acid of density 1,40 g/ml to 1000 ml); silver nitrate 0,0856 mol/l (14,541 g dried 2 h at 150 °C ± 2 °C, in dark glass); sodium chloride 0,0856 mol/l (5,000 g dried 2 h at 110 °C ± 2 °C). Apparatus (5): homogenizing equipment (high-speed rotational cutter or mincer with a plate with holes not exceeding 4,5 mm); laboratory blender with variable speed; silver billet combination electrode or separate indicating silver and glass reference electrodes (the silver electrode tip is cleaned before first use and, if necessary, before each day’s use, and again when the endpoint drifts; coating with silver chloride is unnecessary); magnetic stirrer; pH meter with scale divisions of 10 mV or less and a range of at least ±700 mV; 50 ml pipette; balance 0,1 g. Sampling (6) is not part of the method (ISO 3100-1 recommended); representative sample of at least 200 g. Preparation (7): homogenize so that the temperature does not exceed 25 °C, at least twice through a mincer; airtight container and analysis always within 24 h of homogenization. Determination (8): approx. 50 g to the nearest 0,1 g into a 1000 ml blender jar, add 450 g of water, blend first slowly, then 1–2 min at high speed; immediately pipette 50 ml of the suspension into a tared beaker and weigh (m₁). Titration curve (8.3): 25 ml of NaCl solution diluted to approx. 50 ml with 50 ml of nitric acid is titrated with silver nitrate in increments adjusted to the rate of potential change, 50 ml in total; the inflection point is found with two 45° lines tangent to the curve at the points of greatest curvature (it lies where the curve crosses the parallel line drawn midway between them); the inflection point serves as the endpoint, is rechecked from time to time and redetermined after replacing an electrode or the pH meter; the silver nitrate concentration is calculated from the volume used and adjusted to 0,0856 mol/l. Sample (8.4): add 50 ml of nitric acid to the suspension and titrate in the same way as for the curve (8.3); for chlorides up to 1 % — 10 ml burette; for a series of determinations on the same meat it is best to use the endpoint from that meat’s titration curve rather than from the standard solution. Blank (8.5): steps 8.2.2–8.4 with water instead of the suspension. Calculation (9): w = (V₁ − V₂) × c × 50 × 58,44 / (m₁ × m), where V₁ and V₂ — volumes of silver nitrate in the determination and the blank (ml), c — silver nitrate concentration (mol/l), m₁ — mass of the suspension taken (g), m — mass of the test portion (g); result as NaCl to the nearest 0,1 % (m/m). Precision (10, from an interlaboratory test according to ISO 5725, 95 % probability): repeatability limit r = 0,002 + 0,033·w̄, reproducibility limit R = 0,005 + 0,066·w̄ (w̄ — mean of two results in %). Test report (11): sampling method if known, method used, result(s), final quoted result if repeatability was checked, details not specified in the standard and incidents that may have influenced the result.

STATUS (PKN catalogue cards as of 02.10.2026). The card of PN-ISO 1841-2:2002 (Polish version, published 02-09-2002, 9 pages, price group E) has the “Withdrawn” header: withdrawal date 06-07-2018, Food, Agriculture and Forestry Sector, KT 93 Meat, Eggs and their Products, ICS 67.120.10, “Introduces: ISO 1841-2:1996 [IDT]”; there is NO “Replaced by” field on the card. The three questions for a withdrawn standard: when — 06.07.2018; replaced by what — the card indicates no successor, and the PKN search for “PN-ISO 1841-2” (02.10.2026) shows only this one standard; what changed for the result — nothing in the content of the method: the ISO document that the standard introduced is still in force — the EVS standards catalogue (Estonia) lists ISO 1841-2:1996 as valid from 27.06.1996, with a history consisting of one item (read 02.10.2026). The laboratories thus cite a withdrawn national standard whose content is identical to the valid ISO standard.

HOW MANY LABORATORIES AND IN WHAT FORM (copy of the accreditation scope database, data up to 17.09.2026, read 02.10.2026). The number 1841-2 appears in 8 records at 6 laboratories: AB 076, AB 370, AB 400, AB 483, AB 592, AB 1334. In the current scopes on the PCA website (read 02.10.2026, issues from 06.02.2026 to 07.08.2026) all give “PN-ISO 1841-2:2002”, and AB 076 adds its own document “IB-10 wydanie 5 z dnia 2026.03.27” in one of its two entries. The “Laboratories” tab searches for entries STARTING WITH “PN-ISO 1841-2” and shows all 6 laboratories — checked with the tab query on the production server labcoda.pl on 02.10.2026.

WHAT THE LABORATORIES TEST (PCA entries). Meat and meat products: “Chloride content” from 0,5 to 6,0 % (AB 370), “Chloride content (NaCl)” from 0,25 to 10,00 % (AB 483), “Chloride content” from 0,1 to 21,0 % (m/m), also poultry (AB 592), “Table salt content” from 0,16 to 10,0 % by a titrimetric method (AB 400); canned meat, poultry and vegetable-meat products — “Salt content (NaCl)” from 0,25 to 3,00 % (AB 076), and in AB 076’s second entry the same for sterilized soups and canned vegetables, with its own instruction IB-10; AB 1334 has a shared line “Sodium chloride content” from 0,10 to 20,00 % for cheeses (PN-EN ISO 5943), meat and meat products (this standard) and fruit and vegetables (PN-A-75101-10, PN-EN 12133). Everywhere except AB 400 the technique given is potentiometric titration.

WHERE A SEEMINGLY CORRECT RESULT IS EASY TO GET. Range: the standard applies to products with at least 0,25 % NaCl, and three laboratories give a lower limit below that — AB 592 0,1 %, AB 1334 0,10 % (line shared with other standards) and AB 400 0,16 %; a result below 0,25 % lies outside the range for which the standard established the method and its precision. Test item: soups and canned vegetables (AB 076) are not meat — there the laboratory adds its own instruction. Preparation: the temperature during homogenization may not exceed 25 °C, and the analysis must take place within 24 h of homogenization. Measurement: the suspension is pipetted IMMEDIATELY after blending (8.2.2) — blending according to 8.2.1 is meant to suspend the solids uniformly; for chlorides up to 1 % a 10 ml burette must be used; the endpoint is taken from the curve and redetermined after replacing an electrode or pH meter. Calculation: the blank volume (V₂) is subtracted, and the factor 50 and both masses (m₁ of the suspension and m of the test portion) must correspond to the amounts actually used; the result is expressed as NaCl, although all chlorides are determined. Status: the entry “PN-ISO 1841-2:2002” points to a standard withdrawn by PKN — the content of the method has not changed, because ISO 1841-2:1996 remains in force.

WHAT WE DO NOT STATE. We have the full text of the standard. We give no numerical values from the interlaboratory test other than the formulae for r and R (the standard does not contain them) and no reason for the withdrawal of the standard by PKN — the card does not give one.

Method principle

A portion of approx. 50 g of meat is blended with 450 g of water, 50 ml of the suspension is acidified with nitric acid and titrated potentiometrically with 0,0856 mol/l silver nitrate using a silver electrode to the inflection point of the curve; chlorides are calculated as NaCl in % (m/m) from the titrant volume (minus the blank).

Applications

• Meat and meat products, including poultry — chloride/salt content; 6 laboratories in PCA scopes
• Canned meat, poultry and vegetable-meat products — salt content (NaCl)
• Checking the declared salt content of products with at least 0,25 % NaCl

Key parameters

Standard

Standard number

PN-ISO 1841-2:2002 (wersja polska; ISO 1841-2:1996 IDT) — wycofana przez PKN 06-07-2018 bez wskazania następcy (stan karty na 02.10.2026)

Title (PL)

Mięso i przetwory mięsne — Oznaczanie zawartości chlorków — Część 2: Metoda potencjometryczna

Title (EN)

Meat and meat products — Determination of chloride content — Part 2: Potentiometric method

Step-by-step procedure

1. Sample

   At least 200 g; homogenize (≤ 25 °C, mincer twice), store airtight, analyse within 24 h. PN-ISO 1841-2:2002 withdrawn 06-07-2018 without successor (card as of 02.10.2026).

2. Suspension

   Approx. 50 g (± 0,1 g) + 450 g water in the blender: slowly, then 1–2 min fast; immediately 50 ml of suspension into a tared 250 ml beaker and weigh (m₁).

3. Curve and endpoint

   25 ml NaCl 0,0856 mol/l + water to approx. 50 ml + 50 ml HNO₃; titrate with AgNO₃ up to 50 ml; inflection point by the 45° tangent method; standardize AgNO₃.

4. Sample titration

   Add 50 ml HNO₃ 1 + 49 to the suspension; titrate to the endpoint (10 ml burette for chlorides ≤ 1 %); blank with water instead of suspension.

5. Result

   w = (V₁ − V₂) × c × 50 × 58,44 / (m₁ × m) as NaCl, to the nearest 0,1 % (m/m); repeatability r = 0,002 + 0,033·w̄.

Required equipment and apparatus

Reagents, media and consumables

Health and safety (OHS)

• The standard contains no safety warnings — the laboratory sets the rules for handling silver nitrate and concentrated nitric acid according to the safety data sheets
• TECHNICAL NOTE: the method applies to products with at least 0,25 % NaCl; take the suspension immediately after blending; PN-ISO 1841-2:2002 withdrawn by PKN, ISO 1841-2:1996 still valid

Frequently asked questions