Commission Directive 2004/16/EC of 12 February 2004 laying down the sampling methods and the methods of analysis for the official control of the levels of tin in canned foods (Text with EEA relevance)
Date: 2004-02-12
Institutions: European Commission
Subjects: EU Member State, application of EU law, food inspection, food standard, foodstuff, toxic substance

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Official Journal of the European Union

13.2.2004

COMMISSION DIRECTIVE 2004/16/EC

of 12 February 2004

laying down the sampling methods and the methods of analysis for the official control of the
levels of tin in canned foods

(Text with EEA relevance)

THE COMMISSION OF THE EUROPEAN COMMUNITIES,

(4)

Having regard to the Treaty establishing the European
Community,

Having regard to Council Directive 85/591/EEC of 20
December 1985 concerning the introduction of Community
methods of sampling and analysis for the monitoring of food-
stuffs intended for human consumption (1), as amended by
Regulation (EC) No 1882/2003 of the European Parliament and
of the Council (2), and in particular Article 1 thereof,

The provisions for the sampling and methods of analysis
have been drawn up on the basis of present knowledge
and they may be adapted to take account of advances in
scientific and technological knowledge. Methods
to
analyse for total tin are appropriate for controls on inor-
ganic tin. The possible presence of organic forms of tin
are considered to be negligible in relation to the
maximum levels set for inorganic tin.

(5)

The measures provided for in this Directive are in
accordance with the opinion of the Standing Committee
on the Food Chain and Animal Health,

Whereas:

HAS ADOPTED THIS DIRECTIVE:

(1)

(2)

(3)

Commission Regulation (EC) No 466/2001 of 8 March
2001 setting maximum levels for certain contaminants
in foodstuffs (3), as last amended by Regulation (EC) No
242/2004 (4) fixes maximum limits for inorganic tin in
canned foodstuffs and makes reference to measures
laying down the sampling and analysis methods to be
used.

Article 1

The Member States shall take all measures necessary to ensure
that the sampling for the official control of the levels of tin in
foodstuffs is carried out
in accordance with the methods
described in Annex I to this Directive.

Council Directive 93/99/EEC of 29 October 1993 on
the subject of additional measures concerning the official
control of foodstuffs (5), as amended by Regulation (EC)
No 1882/2003, introduces a system of quality standards
for laboratories entrusted by the Member States with the
official control of foodstuffs.

Article 2

The Member States shall take all measures necessary to ensure
that sample preparation and methods of analyses used for the
official control of the levels of tin in foodstuffs comply with
the criteria described in Annex II to this Directive.

It seems necessary to fix general criteria, which the
method of analysis has to comply with in order to
ensure that laboratories,
in charge of the control, use
methods of analysis with comparable levels of perfor-
mance. It is also of major importance that analytical
results are reported and interpreted in a uniform way in
order to ensure a harmonised enforcement approach
across the European Union. These interpretation rules
are of application for the analytical result obtained on
the sample for official control. In case of analysis for
defence or referee purposes, the national rules apply.

(1) OJ L 372, 31.12.1985, p. 50.
(2) OJ L 284, 31.10.2003, p. 1.
(3) OJ L 77, 16.3.2001, p. 1.
(4) See page 3 of this Official Journal.
(5) OJ L 290, 24.11.1993, p. 14.

Article 3

The Member States shall bring into force the laws, regulations
and administrative provisions necessary to comply with the
provisions of this Directive by 31 December 2004. They shall
forthwith communicate to the Commission the text of those
provisions and a correlation table between those provisions
and this Directive.

When Member States adopt those provisions, their provisions
shall contain a reference to this Directive or shall be accompa-
nied by such a reference on the occasion of their official publi-
cation. Member States shall determine how such reference is to
be made.

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This Directive shall enter into force on the 20th day following its publication in the Official Journal of the
European Union.

This Directive is addressed to the Member States.

Article 4

Done at Brussels, 12 February 2004.

For the Commission

David BYRNE

Member of the Commission

L 42/18

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Official Journal of the European Union

13.2.2004

ANNEX I

METHODS OF SAMPLING FOR OFFICIAL CONTROL OF THE LEVELS OF TIN IN CANNED FOODSTUFFS

1.

Purpose and scope

Samples intended for official checking of the levels of tin in canned foodstuffs shall be taken according to the
methods described below. Aggregate samples thus obtained shall be considered as representative of the lots.
Compliance with maximum levels laid down in Commission Regulation (EC) No 466/2001 shall be established on
the basis of the levels determined in the laboratory samples.

2. Definitions

Lot:

Sublot:

an identifiable quantity of a food commodity delivered at one time and having been deter-
mined by the official to have common characteristics, such as origin, variety, type of packing,
packer, consignor or markings.

designated part of a lot in order to apply the sampling method on that designated part. Each
sublot must be physically separate and identifiable.

Incremental sample: a quantity of material taken from a single place in the lot or sublot.

Aggregate sample:

the combined total of all the incremental samples taken from the lot or sublot.

Laboratory sample:

sample intended for the laboratory.

3. General provisions

3.1. Personnel

Sampling shall be performed by an authorised person as specified by the Member States.

3.2. Material to be sampled

Each lot which is to be examined must be sampled separately.

3.3. Precautions to be taken

In the course of sampling and preparation of the samples precautions must be taken to avoid any changes, which
would affect the tin content, adversely affect the analytical determination or make the aggregate samples unrepre-
sentative.

3.4. Incremental samples

As far as possible incremental samples should be taken at various places distributed throughout the lot or sublot.
Departure from this procedure must be recorded in the record.

3.5. Preparation of the aggregate sample

The aggregate sample is made up by uniting all incremental samples. This aggregate sample is homogenised in the
laboratory.

3.6. Replicate laboratory samples

Replicate laboratory samples for enforcement, trade (defence) and referee purposes shall be taken from the homo-
genised aggregate sample unless this conflicts with Member States' rules on sampling.

3.7. Packaging and transmission of samples

Each sample shall be placed in a clean,
inert container offering adequate protection from contamination and
against damage in transit. All necessary precautions shall be taken to avoid any change in composition of the
sample, which might arise during transportation or storage.

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3.8. Sealing and labelling of samples

Each sample taken for official use shall be sealed at the place of sampling and identified following the Member
State's regulations.

A record must be kept of each sampling, permitting each lot to be identified unambiguously and giving the date
and place of sampling together with any additional information likely to be of assistance to the analyst.

4.

Sampling plans

The sampling method applied shall ensure that the aggregate sample is representative for the lot that is to be
controlled.

4.1. Number of incremental samples

The minimum number of incremental samples to be taken from cans within a lot shall be as given in Table 1. The
incremental samples taken from each can shall be of similar weight, resulting in an aggregate sample (see
point 3.5).

Number of cans (incremental samples) which shall be taken to form the aggregate sample

Table 1

Number of cans in the lot or sublot

Number of cans to be taken

1 to 25

26 to 100

> 100

at least 1 can

at least 2 cans

5 cans

Note that the maximum levels apply to the contents of each can, but for feasibility of testing it is necessary to use
an aggregate sampling approach. If the test result for the aggregate sample is less than but close to the maximum
level and if it is suspected that individual cans might exceed the maximum level then it might be necessary to
conduct further investigations.

4.2. Sampling at retail stage

Sampling of foodstuffs at the retail stage should be done where possible in accordance with the above sampling
provisions. Where this is not possible, other effective sampling procedures at retail stage can be used provided that
they ensure sufficient representativeness for the sampled lot.

5. Compliance of the lot or sublot with the specification

The control laboratory shall analyse the laboratory sample for enforcement in at least two independent analyses,
and calculate the mean of the results.

The lot is accepted if the mean does not exceed the respective maximum level (as laid down in Regulation (EC) No
466/2001) taking into account the measurement uncertainty and correction for recovery.

The lot is non-compliant with the maximum level (as laid down in Regulation (EC) 466/2001) if the mean exceeds
the maximum level beyond reasonable doubt taking into account the measurement uncertainty and correction for
recovery.

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Official Journal of the European Union

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ANNEX II

SAMPLE PREPARATION AND CRITERIA FOR METHODS OF ANALYSIS USED IN OFFICIAL CHECKING OF
THE LEVELS OF TIN IN CANNED FOODSTUFFS

1.

Precautions and general considerations for tin

The basic requirement is to obtain a representative and homogeneous laboratory sample without introducing
secondary contamination.

The analyst should ensure that samples do not become contaminated during sample preparation. Wherever
possible, apparatus coming into contact with the sample should be made of inert materials e.g. plastics such as
polypropylene, PTFE etc., and these should be acid cleaned to minimise the risk of contamination. High quality
stainless steel can be used for cutting edges.

All of the sample material received by the laboratory is to be used for the preparation of test material. Only
very finely homogenised samples give reproducible results.

There are many satisfactory specific sample preparation procedures which may be used. Those described in the
CEN Standard on the ‘Determination of trace elements — Performance criteria and general consideration’ have
been found to be satisfactory (1) but others may be equally valid.

2.

Treatment of the sample as received in the laboratory

Finely grind (where relevant) and mix thoroughly the complete aggregate sample using a process that has been
demonstrated to achieve complete homogenisation.

3.

Subdivision of samples for enforcement and defence purposes

The replicate samples for enforcement, trade (defence) and referee purposes shall be taken from the homoge-
nised material unless this conflicts with Member States' rules on sampling.

4.

Method of analysis to be used by the laboratory and laboratory control requirements

4.1.

Definitions

A number of the most commonly used definitions that the laboratory will be required to use are given below:

r

sr

RSDr

R =

sR

RSDR

= Repeatability,

the value below which the absolute difference between 2 single test results
obtained under repeatability conditions (i.e., same sample, same operator, same apparatus, same
laboratory, and short interval of time) may be expected to lie within a specific probability (typi-
cally 95 %) and hence r = 2,8 × sr.

= Standard deviation, calculated from results generated under repeatability conditions.

= Relative standard deviation, calculated from results generated under repeatability conditions [(sr/

) × 100], where

is the average of results over all laboratories and samples.

= Reproducibility,

the value below which the absolute difference between single test results
obtained under reproducibility conditions (i.e., on identical material obtained by operators in
different laboratories, using the standardised test method), may be expected to lie within a
certain probability (typically 95 %); R = 2,8 × sR.

= Standard deviation, calculated from results under reproducibility conditions.

= Relative standard deviation calculated from results generated under reproducibility conditions

[(sR/

) × 100].

HORRATr = the observed RSDr divided by the RSDr value estimated from the Horwitz equation using the

assumption r = 0,66R.

HORRATR = the observed RSDR value divided by the RSDR value calculated from the Horwitz equation (2).

U

= the expanded uncertainty, using a coverage factor of 2 which gives a level of confidence of

approximately 95 %.

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4.2.

General requirements

Methods of analysis used for food control purposes must comply with the provisions of items 1 and 2 of the
Annex to Council Directive 85/591/EEC of 20 December 1985 concerning the introduction of Community
methods of sampling and analysis for the monitoring of foodstuffs intended for human consumption.

4.3.

Specific requirements

Where no specific methods for the determination of tin in canned foodstuffs are prescribed at Community level,
laboratories may select any validated method provided the selected method meets the performance criteria indi-
cated in Table 2. The validation should ideally include a certified reference material.

Table 2

Performance criteria for methods of analysis for tin

Parameter

Value/comment

Applicability

Foods specified in Regulation (EC) No 242/2004

Detection limit

No more than 5 mg/kg

Limit of quantification

No more than 10 mg/kg

Precision

Recovery

HORRATr or HORRATR values of less than 1,5 in the validation collaborative trial

80 % to 105 % (as indicated in the collaborative trial)

Specificity

Free from matrix or spectral interferences

4.3.1.

Pe r for ma nc e Cri te ri a — U nc er ta i nty F u nc ti on A p pr oa ch

However, an uncertainty approach may also be used to assess the suitability of the method of analysis to be
used by the laboratory. The laboratory may use a method which will produce results within a maximum stand-
ard uncertainty. The maximum standard uncertainty can be calculated using the following formula:

Uf ¼

q
ﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃ
Þ2
LOD=2
ð

Þ2 þ 0,1C
ð

where:

Uf

is the maximum standard uncertainty

LOD is the limit of detection of the method

C

is the concentration of interest

If an analytical method provides results with uncertainty measurements less than the maximum standard uncer-
tainty, the method will be equally suitable to one which meets the performance characteristics given in Table 2.

4.4.

Recovery calculation and reporting of results

The analytical result is to be reported corrected or uncorrected for recovery. The manner of reporting and the
level of recovery must be reported. The analytical result corrected for recovery is used for checking compliance
(see Annex I, point 5).

The analyst should note the ‘Harmonised Guidelines for the Use of Recovery Information in Analytical Measure-
ment’ (3) developed under IUPAC/ISO/AOAC. These Guidelines assist when determining recovery factors.

The analytical result has to be reported as x +/- U whereby x is the analytical result and U is the measurement
uncertainty.

4.5.

Laboratory quality standards

Laboratories must comply with Council Directive 93/99/EEC of 29 October 1993 on the subject of additional
measures concerning the official control of foodstuffs.

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4.6.

Other considerations for the analysis

Pr ofi ci e nc y te sti n g

Participation in appropriate proficiency testing schemes which comply with the ‘International Harmonised
Protocol for the Proficiency Testing of (Chemical) Analytical Laboratories’ (4) developed under the auspices of
IUPAC/ISO/AOAC.

Some of these schemes specifically include the determination of tin in foods, and participation in such a scheme
is recommended rather than a general scheme for the determination of metals in foods.

Inter n al q ua lity c ontr ol

Laboratories should be able to demonstrate that they have internal quality control procedures in place. Examples
of these are the ‘ISO/AOAC/IUPAC Guidelines on Internal Quality Control in Analytical Chemistry Laboratories’
(5).

Sa mple pr e par ati on

Care must be taken to ensure that all the tin in the sample is taken into solution for analysis. In particular it is
recognised that the sample dissolution procedure must be such that no hydrolysed SnIV species is precipitated
(i.e. species such as stannic oxide SnO2, Sn(OH)4, SnO2.H2O).

Keep prepared samples in 5 mol/l HCl. However, SnCl4 is easily volatilised and so solutions should not be
boiled.

REFERENCES

1. BS EN 13804:2002: Foodstuffs — Determination of trace elements — Performance criteria, general considerations

and sample preparation, CEN, Rue de Stassart 36, B-1050 Brussels.

2. W Horwitz, ‘Evaluation of Analytical Methods for Regulation of Foods and Drugs’, Anal. Chem., 1982, 54, 67A —

76A.

3. ISO/AOAC/IUPAC Harmonised Guidelines for the Use of Recovery Information in Analytical Measurement. Edited
Michael Thompson, Steven L R Ellison, Ales Fajgelj, Paul Willetts and Roger Wood, Pure Appl. Chem., 1999, 71, 337
— 348.

4. ISO/AOAC/IUPAC International Harmonised Protocol for Proficiency Testing of (Chemical) Analytical Laboratories,
Edited by M Thompson and R Wood, Pure Appl. Chem., 1993, 65, 2123 — 2144 (Also published in J. AOAC Inter-
national, 1993, 76, 926).

5. ISO/AOAC/IUPAC International Harmonised Guidelines for Internal Quality Control in Analytical Chemistry Labora-

tories, Edited by M Thompson and R Wood, Pure Appl. Chem., 1995, 67, 649 — 666.