💧 Moisture Content of Meat and Meat Products — Drying with Sand and Distillation

Food Chemistry PN-ISO 1442

Overview

STATUS (as of 02.11.2026). PN-ISO 1442:2000 — Polish version, “Meat and meat products — Determination of water content (reference method)”, published on 14.06.2000, implements ISO 1442:1997 [IDT], replaced PN-A-82110:1973; the PKN catalogue card has no withdrawal note (read on 02.11.2026). At the international level ISO 1442:1997 was withdrawn on 28.08.2023 and replaced by the third edition, ISO 1442:2023; there is no Polish adoption of that edition in the PKN catalogue. Changes according to the foreword of the 2023 edition: a second method (distillation) was added, the order of the clauses was rearranged, the scope of the direct drying method was modified and the bibliography was updated. The description follows the 2023 edition (iTeh preview with clauses 1–9); the drying procedure is the same in both editions, with the differences given below.

SCOPE AND DEFINITION (clauses 1 and 3). Two reference methods for the determination of moisture content in meat and meat products. Direct drying applies to products with low amounts of volatile substances in addition to moisture; distillation — to products with high amounts of them. Moisture content is the loss in mass in the drying method or the content of water collected in the distillation method, divided by the mass of the test portion, as a percentage by mass.

SAMPLE (clauses 5–6). Sampling is not part of the standard (the 2023 edition recommends CAC/GL 50-2004, the 1997 edition — ISO 3100-1); representative sample of at least 200 g. The sample is homogenized with a high-speed rotational cutter or a mincer with a plate with holes not exceeding 4.0 mm in diameter (mincer — at least twice) so that its temperature does not rise above 25 °C; frozen samples are first thawed at 15 °C to 25 °C (2023 edition). The prepared sample is analysed as soon as practicable, always within 24 h after homogenization; if it cannot be tested at once, it is kept sealed at 4 °C to 7 °C (2023 edition).

DIRECT DRYING (clause 7). Clean, acid-washed sand passing through a sieve of 1.4 mm aperture and retained on a 250 µm sieve, dried before use at 150 °C to 160 °C and stored in an airtight bottle; unwashed sand is cleaned with running water and by boiling with hydrochloric acid (1 + 1) for 30 min, repeated until the acid no longer turns yellow after boiling, then washed with distilled water until the chloride test is negative. Apparatus: a flat dish (glass — in the 2023 edition, porcelain or metal, for example nickel, aluminium or stainless steel) at least 60 mm in diameter and about 25 mm high, a thin glass rod flattened at one end, slightly longer than the diameter of the dish, a drying oven at (103 ± 2) °C, a desiccator with an efficient desiccant (for example silica gel), an analytical balance weighing to the nearest 0.001 g. Sand in an amount three to four times the mass of the test portion is put into the dish, the dish with the sand and the rod is dried for 30 min at 103 °C, cooled in the desiccator and weighed (m₀). 5 g to 8 g of the sample are added and weighed with the rod (m₁), mixed with the sand by means of the rod (if mixing is difficult — with ethanol added, which is evaporated gently before drying), dried for 2 h at 103 °C, cooled in the desiccator and weighed. Heating, cooling and weighing are repeated until the results of two successive weighings (m₂), separated by one hour of drying, differ by not more than 0.1 % of the mass of the test portion. Moisture content w = (m₁ − m₂) / (m₁ − m₀) · 100 %, the result to one decimal place. Repeatability limit r = 0.593 % + 0.001 7 · w̄, reproducibility limit R = 0.797 % + 0.004 71 · w̄ (w̄ — mean of the two results).

DISTILLATION (clause 8, 2023 edition only). The water in the sample is co-distilled with toluene or xylene in a moisture analyser and its content is calculated from the volume of water collected. Toluene or xylene is saturated with water, the water layer is separated and the solvent is distilled. Apparatus: a 250 ml distillation flask with an adjustable heating sleeve, a condenser tube and a graduated water-receiving tube (capacity 5 ml, scale division 0.1 ml, capacity error less than 0.1 ml); balance weighing to the nearest 0.001 g. The test portion is chosen so that 2 ml to 5 ml of water distil over and the sample occupies not more than 2/3 of the flask volume; 75 ml of freshly distilled toluene (or xylene) are added, the receiving tube is filled with the solvent and a blank test (V₀) is run in parallel. Distillation proceeds slowly, about two drops per second, until most of the water has distilled over, then at about four drops per second; when the water volume no longer increases, the condenser is rinsed with solvent and droplets on its walls are wiped off with a copper wire with a small piece of rubber. The water volume (V) is read when the level in the receiving tube has remained unchanged for 10 min. w = (V − V₀) · ρ / m · 100 %, where ρ is the density of water and m the mass of the sample; the result with three significant figures.

SECOND SOURCE. The Nordic NMKL methods also determine moisture in meat and in foods by drying at 102 °C to 105 °C (NMKL No. 23 — withdrawn in 2022, NMKL No. 206 of 2024), but with a different drying time — the figures in this description come from ISO 1442 only.

WHAT WE DO NOT GIVE HERE. The precision of the distillation method and the details of the interlaboratory test (informative Annex A of the 2023 edition) — that part of the standard is not in the preview.

Method principle

Direct drying: a test portion of the sample (5 g to 8 g) is mixed thoroughly with acid-washed sand and dried at (103 ± 2) °C — first for 2 h, then for 1 h at a time — to constant mass, i.e. until successive weighings differ by not more than 0.1 % of the mass of the test portion. Moisture content is the loss in mass relative to the mass of the test portion.

Distillation (2023 edition): the water in the sample is co-distilled with toluene or xylene in an apparatus with a graduated receiving tube, and its content is calculated from the volume of water collected after subtraction of the blank. The method is used for products containing large amounts of volatile substances in addition to water.

Applications

• Meat and meat products with low amounts of volatile substances other than water — direct drying (ISO 1442:2023, clauses 1 and 7; the only method of PN-ISO 1442:2000)
• Meat and meat products with high amounts of volatile substances other than water — distillation with toluene or xylene (ISO 1442:2023, clause 8)
• Frozen samples — after thawing at 15 °C to 25 °C (ISO 1442:2023, clause 6)

Key parameters

Standard

Standard number

PN-ISO 1442:2000

Title (PL)

Mięso i przetwory mięsne — Oznaczanie zawartości wody (metoda odwoławcza)

Title (EN)

Meat and meat products — Determination of moisture content — Reference method

Step-by-step procedure

1. Preparation of the sample

   At least 200 g; homogenization without exceeding 25 °C (mincer — at least twice); frozen samples thawed at 15–25 °C; analysis within 24 h after homogenization (5, 6).

2. Dish with sand

   Sand three to four times the test portion mass; dish, sand and rod 30 min at 103 °C, cooled in the desiccator, weighed (m₀) (7.3.2).

3. Test portion and mixing

   5 g to 8 g of sample, weighed with the rod (m₁); mixed with the sand, if necessary with ethanol evaporated before drying (7.3.3–7.3.4.1).

4. Drying to constant mass

   First drying 2 h at 103 °C, cooling in the desiccator, weighing; then 1 h at a time until two successive weighings (m₂) differ by not more than 0.1 % of the test portion mass (7.3.4.1–7.3.4.2).

5. Result of drying

   w = (m₁ − m₂) / (m₁ − m₀) · 100 %, one decimal place; checking repeatability — two determinations under repeatability conditions (7.3.1, 7.4).

6. Or: distillation

   Test portion yielding 2 ml to 5 ml of water, not more than 2/3 of the flask volume; 75 ml of freshly distilled toluene or xylene; blank test (V₀); distillation at about two, then about four drops per second; reading V after 10 min without change in level; w = (V − V₀) · ρ / m · 100 % (8.4–8.5).

Required equipment and apparatus

Reagents, media and consumables

Health and safety (OHS)

• Toluene and xylene are flammable and harmful — the distillation is carried out in an apparatus with a heating sleeve (8.3.1); follow the safety data sheets
• The hydrochloric acid for cleaning the sand is boiled — follow the safety data sheet

Frequently asked questions