Commission Regulation (EC) No 273/2008 of 5 March 2008 laying down detailed rules for the application of Council Regulation (EC) No 1255/1999 as regards methods for the analysis and quality evaluation of milk and milk products (repealed) (c. 273)

ANNEX XVIII (Article 14)

DETERMINATION OF MOISTURE CONTENT IN DRIED CREAM

1. SCOPE

This Annex specifies a method for the determination of the moisture content of dried cream.

2. TERMS AND DEFINITIONS

For the purpose of this Annex, the following definition applies.

Moisture content: the loss of mass determined by the procedure specified in this International Standard.

It is expressed as a percentage by mass.

3. PRINCIPLE

Drying of a test portion at 102 ± 2 °C to constant mass and weighing to determine the loss of mass.

4. APPARATUS

Usual laboratory equipment and, in particular, the following:

4.1. Analytical balance, capable of weighing to the nearest 1 mg, with a readability of 0,1 mg.

4.2. Drying oven, well ventilated, capable of being maintained thermostatically at 102 ± 2 °C throughout the working space.

4.3. Desiccator, provided with freshly dried silica gel with hygrometric indicator or another effective desiccant.

4.4. Flat-bottomed dishes, depth of approximately 25 mm, diameter of approximately 50 mm, and made of appropriate material (for example glass, stainless steel, nickel or aluminium), provided with well-fitting, readily removable lids.

4.5. Bottles, with tight-fitting stoppers, for mixing the laboratory samples.

5. SAMPLING

It is important that the laboratory receive a test sample which is truly representative and has not been damaged or changed during transport or storage.

Sampling is not part of the method specified in this International Standard. A recommended sampling method is given in ISO 707|IDF 50.

Store the sample in such a way that deterioration and change in composition are prevented.

6. PREPARATION OF TEST SAMPLE

Thoroughly mix the test sample by repeatedly shaking and inverting the container (if necessary, after having transferred all test samples to an air-tight container of sufficient capacity to allow this operation to be carried out).

In case complete homogeneity is not attained by this procedure, take the test portions (for two single determinations) from the prepared test sample at two points as far apart as possible.

7. PROCEDURE

7.1. Preparation of the dish

7.1.1. Heat an uncovered dish and its lid (4.4) in the oven (4.2), set at 102 ± 2 °C, for at least 1 h.

7.1.2. Place the lid on the dish, transfer the covered dish to the desiccator (4.3), allow to cool to the temperature of the balance room and weigh to the nearest 1 mg recording the weight to 0,1 mg.

7.2. Test portion

Transfer approximately 1 to 3 g of the prepared test sample (6) into the dish, cover with the lid and weigh to the nearest 1 mg recording the weight to 0,1 mg.

7.3. Determination

7.3.1. Uncover the dish and place it with its lid in the oven (4.2), set at 102 ± 2 °C, for 2 h.

7.3.2. Replace the lid, transfer the covered dish to the desiccator, allow to cool to the temperature of the balance room and weigh to the nearest 1 mg recording the weight to 0,1 mg.

7.3.3. Uncover the dish and heat it again, with its lid, in the oven for 1 h. Then repeat operation 7.3.2.

7.3.4. Repeat the heating and the weighing procedure until the mass decreases by 1 mg or less, or increases between two successive weightings.

Take for the calculation the lowest mass recorded.

8. CALCULATION AND EXPRESSION OF RESULTS

8.1. Calculation

The moisture content, expressed in g/100g, is equal to:

where:

m₀ is the mass, in grams, of the dish and the lid (7.1.2);

m₁ is the mass, in grams, of the dish, the lid and the test portion before drying (7.2);

m₂ is the mass, in grams, of the dish, the lid and the test portion after drying (7.3.4).

Report the result to two decimal places.

9. PRECISION

Note: The values for repeatability and reproducibility were derived from the results of an interlaboratory test (see Steiger, G. Bulletin of IDF No 285/1993, p. 21-28) carried out in accordance with IDF Standard 135B:1991. Milk and milk products — Precision characteristics of analytical methods — Outline of collaborative study procedure.

9.1. Repeatability

The absolute difference between two independent single test results, obtained using the same method on identical test material in the same laboratory by the same operator using the same equipment within a short interval of time, will in not more than 5 % of cases be greater than 0,20 g of moisture per 100 g of product.

9.2. Reproducibility

The absolute difference between two independent single test results, obtained using the same method on identical test material in different laboratories by different operators using different equipment will in not more than 5 % of cases be greater than 0,40 g of moisture per 100 g of product.

10. TEST REPORT

The test report shall specify

• all information necessary for the complete identification of the sample,

• the sampling method used, if known,

• the test method used with reference to this International Standard,

• all operating details not specified in this International Standard, or regarded as optional, together with details of any incidents which may have influenced the test result(s).

The test result(s) obtained, and if the repeatability has been checked, the final quoted result obtained.