In cases where detailed sampling procedures are given by the relevant legislation, these procedures are followed. In all other cases a sample of at least 3 sample units taken randomly from the consignment submitted to control is used. A composite sample may be prepared. The result obtained is compared with the legal limits by calculation of a 95 % confidence interval as 2 x standard deviation, where the relevant standard deviation depends on whether (1) the method is validated through international collaboration with values for σr and σR or (2) in the case of in-house validation, an internal reproducibility has been calculated. This confidence interval will then equate to the measurement uncertainty of the result.

In this case the repeatability standard deviation σr and the reproducibility standard deviation σR have been established and the laboratory can demonstrate compliance with the performance characteristics of the validated method.

Calculate the arithmetic mean $\bar{x}$ of the n repeated measurements.

Calculate the expanded uncertainty (k = 2) of $\bar{x}$ as

$\mathrm{U\; =\; 2}\sqrt{{\sigma }_2^R\mathrm{ – }\frac{\mathrm{n – 1}}{n}{\sigma }_2^r}$

If the final result x of measurement is calculated using a formula of the form x = y 1 + y 2, x = y 1 – y 2, x = y 1 · y 2 or x = y 1 / y 2 the usual procedures for combining standard deviations in such cases must be followed.

The consignment is judged to be not in compliance with the upper legal limit UL if

$\bar{x}\mathrm{ \; –}U>\mathrm{UL}$ ;

otherwise it is judged to be in compliance with UL.

The consignment is judged to be not in compliance with the lower legal limit LL if

$\bar{x}+U<\mathrm{LL}$ ;

otherwise it is judged to be in compliance with LL.

In cases where methods not specified in this Regulation are used and precision measures have not been established an in-house validation must be carried out. Internal repeatability standard deviation sir and the internal reproducibility standard deviation siR have to be used instead of σr and σ R , resp., in the formulae for the computation of the expanded uncertainty U.

The decision rules are as under (1). However, if the consignment is judged to be not in compliance with the legal limit the measurements must be repeated with the method specified in this Regulation and the decision reached according to (1).

The following procedures are applicable if scoring methods are used (IDF Standard 99C:1997).

At least ten samples will be analysed as blind duplicates by an assessor within a period of 12 months. This will usually happen in several sessions. The results for individual product characteristics are evaluated using the following formula:

$w_1=1+\left(\left(\Sigma {\left(x_{i1}{\mathrm{–\; x}}_{\mathrm{i2}}\right)}^2\right)\mathrm{/n}\right)$

where:

w1 repeatability index xi1 score for the first evaluation of sample xi xi2 score for the second evaluation of sample xi n number of samples

The samples to be evaluated should reflect a broad quality range. wI should not exceed 1,5 (5-point scales).

This index should be used to check whether an assessor uses the same scale for quality evaluation as an experienced group of assessors. The scores obtained by the assessor are compared with the average of the scores obtained by the assessor group.

The following formula is used for the evaluation of results:

$D_1\mathrm{=\; 1\; +}\left(\Sigma \left[{\left(x_{\mathrm{i1}}{\overline{\mathrm{–\; x}}}_{\mathrm{i1}}\right)}^2+{\left(x_{\mathrm{i2}}{\overline{\mathrm{–\; x}}}_{\mathrm{i2}}\right)}^2\right]\right)/\left(\mathrm{2n}\right)$

where:

xi1; xi2 see section (A) ${\bar{x}}_{\mathrm{i1}}$ ; ${\bar{x}}_{\mathrm{i2}}$ average score of the assessor group for the first and second evaluation respectively of sample xi n number of samples (at least 10 per 12 months).

The samples to be evaluated should reflect a broad quality range. DI should not exceed 1,5 (5-point scales).

Member States must notify any difficulties encountered when applying this procedure.

Where individual assessors are found to exceed the 1,5 limit for Deviation or Repeatability indices, the Official authority expert/s must perform one or more random ‘Re-performance’ checks on samples graded by them over the next few weeks, or perform one or more ‘Accompanied’ checks with those assessors. Close monitoring is necessary to decide whether to retain their services. Findings should be documented and retained as proof of follow up action.

Where applicable, a test must be organised at least once per year to compare the results obtained by assessors from different regions. If significant differences are observed, the necessary steps should be taken to identify the reasons and arrive at comparable results.

Member States may organise tests to compare the results obtained by their own assessors and by assessors from neighbouring Member States. Significant differences should lead to an in-depth investigation with the aim of arriving at comparable results.

Member States should notify the Commission of the results of these comparisons.

The purpose of this procedure for sensory evaluation of butter is to provide a uniform method applicable in all Member States.

Refer to the current IDF International Standard for Milk and Milk Products, IDF 99 — Parts 1, 2, 3 on Sensory Evaluation, for further detail.

‘Sensory evaluation’ (assessment) means the examination of the attributes of a product by the sense organs.

‘Panel’ means a group of selected assessors working, during the assessment, without intercommunication, and without influencing one another.

‘Assessor’ is defined as someone chosen for his/her ability to perform a sensory test. This type of assessor may have limited experience.

‘Expert Assessor’ is defined as someone with a high degree of sensory sensitivity and experience of sensory methodology, who is able to make consistent and reliable sensory assessments of various products. This type of assessor will have a good long term sensory memory.

‘Scoring’ means sensory evaluation by a panel, using a numerical scale. A nomenclature of defects must be used.

‘Grading’ means a quality classification which is performed on the basis of scoring.

‘Control documents’: documents used to record the individual scores for each attribute and the final grade of the product. (This document may also be used to record chemical composition.)

Refer to ISO 8589 and ISO/DIS 22935-2 | IDF 99-2 par 7 for more details.

Precautions must be taken in order that the assessors in the test room are not influenced by external factors.

The test room must be free from foreign odours and easy to clean. The walls must be of a light colour and non reflective.

The test room and its lighting must be such that the properties of the products to be scored are not affected.

The room must be equipped with appropriate thermostatic control to enable a constant temperature of butter to be maintained. Butter should have a temperature of 12 °C (±2 °C) at the time of grading.

The number of assessors in the panel should be uneven, the minimum number being three. The majority must be employees of the competent authority or authorised persons not employed by the dairy industry.

A panel Leader shall be responsible for the entire procedure and may participate in the panel.

A number of factors must be taken into account before evaluation in order to obtain optimal performances from the subjects:

subjects must not be suffering from an illness which could affect their performance. In such a case, the assessor concerned should be replaced on the panel by another, subjects must be on time to take part in the evaluation and make sure that they have enough time to make their evaluation, subjects must not use strong-smelling substances like perfume, after-shave lotion, deodorant, etc. and should avoid eating strong-flavoured (e.g. highly spiced) food, etc., subjects may not smoke, eat or drink anything other than water during the half hour before the evaluation.

All Assessors should participate in regular sensory evaluation panels to maintain their competence. The frequency will depend on the volume and throughput of butter, and where possible, should be at least one panel per month.

Senior Assessors should also participate in a number of panels each year, and where possible, at least once per quarter.

It is essential that the identity of the samples is concealed during the assessment so that any possible bias is avoided. The samples should be coded.

This should be organized prior to the evaluation. Requirement for temperature of butter during its transportation to the test room should be set (6 °C ± 2 °C).

When the sensory evaluation is carried out at a cold store, the sample is taken using a butter trier. If the sensory evaluation is carried out at another location other than the cold store, then at least a 500 g sample should be taken. During the evaluation, the butter should have the temperature of 12 °C (±2 °C) (refer: in ISO/DIS 22935-2 | IDF 99-2 the evaluation temperature of butter is 14 °C ± 2 °C). Large deviations should be avoided at all cost.

A panel leader who must be an official employee of the competent authority and may be a member of the panel must be generally responsible for the entire procedure. He/she must record the individual scores for each attribute in the control document and certify whether the product is accepted or rejected.

Refer to the appended table 2.

FIL-IDF 99C:1997 Sensory evaluation of dairy products by scoring — Reference method

ISO/DIS 22935 | IDF 99 International Standard for Milk and Milk Products — Sensory analysis — Parts 1-3

ISO 8586-1 Sensory analysis — General guidance for selection, training and monitoring of assessors — Part 1

ISO 8589 Sensory analysis — General guidance for the design of test rooms

FIL-IDF 112A:1989 Butter — Determination of water dispersion value

Butter scoring

Table 2.
The defects mentioned under ‘good’ are only very small deviations from the ideal type.
Appearance			Consistency			Flavour + aroma
Points	No	Remarks	Points (quality class)	No	Remarks	Points (quality class)	No	Remarks
5		Very good ideal type highest quality (equal dry)	5		Very good ideal type highest quality (well spreadable)	5		Very good ideal type highest quality (absolutely pure finest aroma)
4		Good no evident defects	4	17 18	Good hard soft	4		Good no evident defects
3	1 2 3 4 5 6 7 8	Fair (slight defects) loose (free), moisture not uniform, two coloured streaky mottled, marbled speckled oil separation overcoloured weak, open texture	3	14 15 16 17 18	Fair (slight defects) short, brittle, crumbly pasty, doughy, greasy sticky hard soft	3	21 22 25 27 33 34 35	Fair (slight defects) unclean foreign flavour acid cooked flavour, scorched flavour feed flavour coarse, bitter oversalted
2	1 3 4 5 6 10 11 12	Poor (evident defects) loose (free) moisture streaky mottled, marbled speckled oil separation foreign matter mouldy undissolved salt	2	14 15 16 17 18	Poor (evident defects) short, brittle, crumbly pasty, doughy, greasy sticky hard soft	2	21 22 23 25 32 33 34 35 36 38	Poor (evident defects) unclean foreign flavour stale acid oxidized flavour, metallic flavour feed flavour coarse, bitter oversalted musty-flat, putrid chemical flavour
1	1 3 4 5 6 7 9 10 11 12	Very poor (strong defects) loose (free) moisture streaky mottled, marbled speckled oil separation overcoloured granular foreign matter mouldy undissolved salt	1	14 15 16 17 18	Very poor (strong defects) short, brittle, crumbly pasty, doughy, greasy sticky hard soft	1	22 24 25 26 28 29 30 31 32 34 35 36 37 38	Very poor (strong defects) foreign flavour cheesy, lactic cheese flavour acid yeasty mould flavour rancid oily, fishy tallowy oxidized flavour, metallic flavour coarse, bitter oversalted musty-flat, putrid malty chemical flavour

Table of butter defects

This designation should be used as seldom as possible and only when the defect cannot be described more accurately.

I. Appearance

1. loose (free), moisture

2. not uniform, two coloured

3. streaky

4. mottled, marbled

5. speckled

6. oil separation

7. overcoloured

8. weak (open texture)

9. granular

10. foreign matter

11. mouldy

12. undissolved salt

II. Consistency

14. short, brittle, crumbly

15. pasty, doughy, greasy

16. sticky

17. hard

18. soft

III. Flavour and aroma

20. without flavour

21. unclean

22. foreign flavour

23. stale

24. cheesy, lactic cheese flavour

25. acid

26. yeasty

27. (a) cooked flavour

(b) scorched flavour

28. mouldy flavour

29. rancid

30. oily, fishy

31. tallowy

32. (a) oxidized flavour

(b) metallic flavour

33. feed flavour

34. coarse, bitter

35. oversalted

36. musty-flat, putrid

37. malty

38. chemical flavour

This method lays down a method for the determination of the content of the triglyceride of enanthic acid in butter-oil, butter and cream.

Enanthic acid content: content of the triglyceride of enanthic acid determined by the procedure specified in this method.

Milk fat is extracted from the different products according to ISO 14156 | IDF 172:2001. The quantitative determination of the content of the triglyceride of enanthic acid in the extracted fat is determined by capillary gas chromatography (GC). The result obtained for the sample is evaluated by reference to the triglyceride of caproic acid as internal standard.

It is important that the laboratory receives a 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 IDF: standard 50C:1995 or ISO 707-1997 — Milk and milk products — Methods of sampling.

The method describes a procedure for the quantitative determination of vanillin in concentrated butter, butter or cream.

Extraction of a known quantity of sample with a mixture of isopropanol/ethanol/acetonitrile (1:1:2). Precipitation of the majority of fat by cooling between -15 °C and -20 °C, followed by centrifugation.

After dilution with water, determination of the vanillin content by high-performance liquid chromatography (HPLC).

Calculate the average peak area (or height) (AC), of the vanillin peaks associated with the bracketing duplicate injections for each batch of test solutions (four areas or heights in total).

Calculate the response factor (R):

$\mathrm{R\; =\; AC/CM}$

where CM is the mass of vanillin in mg (4.5.1).

The content (mg/kg) of vanillin I in the test sample is given by:

$\mathrm{C\; =}\left[\left(\mathrm{AS\; \times \; 20\; \times \; 0,96}\right)/\left(\mathrm{SM\; \times \; R}\right)\right]$

where:

AS peak area or height of the vanillin peak of the test sample SM mass of test sample in g (5.1.1, 5.1.2 or 5.1.3).

20 factor which takes into account the dilutions of the standard and the test sample 0,96 correction factor for the fat content in first dilution of the test sample

The method describes a procedure for the quantitative determination of the ethyl ester of beta-apo-8'-carotenic acid (apo-carotenic ester) in concentrated butter and butter. The apo-carotenic ester is the sum of all substances present in an extract of samples obtained under the conditions described in the method which absorb light at 440 nm.

The butterfat is dissolved in light petroleum and the absorbance measured at 440 nm. The apo-carotenic ester content is determined by reference to an external standard.

The method describes a procedure for the quantitative determination of sitosterol or stigmasterol in butter and concentrated butter. Sitosterol is taken to be the sum of β-sitosterol and 22 dihydro-β-sitosterol, other sitosterols are assumed to be insignificant.

The butter or concentrated butter is saponified with potassium hydroxide in ethanolic solution and the unsaponifiables are extracted with diethyl ether.

The sterols are transformed into trimethyl-silyl ethers and are analysed by capillary-column gas chromatography with reference to an internal standard/betulin.

Detection of cows’ milk and caseinate in cheeses made from ewes’ milk, goats’ milk, buffalos’ milk or mixtures of ewes’, goats’ and buffalos’ milk by isoelectric focusing of γ-caseins after plasminolysis.

The method is suitable for sensitive and specific detection of native and heat-treated cows’ milk and caseinate in fresh and ripened cheeses made from ewes’ milk, goats’ milk, buffalos’ milk or mixtures of ewes’, goats’ and buffalos’ milk. It is not suitable for the detection of milk and cheese adulteration by heat-treated bovine whey protein concentrates.

ISO standard 8261

ISO standard 4831

Samples corresponding to 1 g of butter or 0,1 g of skimmed-milk powder or casein/caseinates are inoculated in the culture medium.

Three tubes are inoculated per sample.

If the 3 tubes produce 3 negative results, the result is ‘compliant’

If the 3 tubes produce 2 or 3 positive results, the result is ‘non-compliant’

If the 3 tubes produce 2 negative results, the analysis is redone twice (with two tubes)

If the 2 results are negative, the result is ‘compliant’ If at least 1 result is positive, the result is ‘non-compliant’.

Determination of lactose in compound feedingstuffs.

The content of lactose is defined as the percentage by mass as determined by the procedure described.

The anhydrous lactose content is expressed as g per 100 g.

The compound feedingstuff is reconstituted with water. A ‘Biggs’ solution is added to a dilute weighed aliquot to precipitate out the fat and the protein component fractions of the compound feedingstuff. The sample is filtered (or centrifuged) and the filtrate (or supernatant) is injected on a cation exchange HPLC column in the lead form using HPLC grade water as the mobile phase. The eluted lactose is detected by a differential refractometer.

It is important that the laboratory receives a sample taken according to ISO 707/IDF 50, which is truly representative and has not been damaged during transport or storage.