Foodstuffs Rules, 2005

L.N. 241 of 2005

VETERINARY SERVICES ACT

(CAP. 437)

Sampling Methods and methods of analysis for the official

control of dioxins and the determination of dioxin-like PCBs in

Foodstuffs Rules, 2005

IN exercise of the powers conferred under article 25 of the

Veterinary Services Act, the Minister for Rural Affairs and the

Environment, in agreement with the Minister of Health, the Elderly

and Community Care, has made the following rules>-

(1) The title of these rules is the Sampling Methods and Title and scope.

methods of analysis for the official control of dioxins and the

determination of dioxin-like PCBs in Foodstuffs Rules, 2005.

(2) The scope of these rules is to implement the rules found

under European Union Council Directive 2002#69#EC on the sampling

methods and the methods of analysis for the official control of dioxins

and the determination of dioxin-like PCBs in foodstuffs.

METHODS OF SAMPLING FOR OFFICIAL CONTROL OF THE LEVELS OF DIOXINS

(PCDD/PCDF) AND THE

DETERMINATION OF DIOXIN-LIKE PCBsIN CERTAIN FOODSTUFFS

1. Purpose and scope

Samples intended for the official control of the levels of dioxins (PCDD/PCDF) content, as well for the

determination of the content of dioxin-like PCBs (1) in foodstuffs shall be taken according to the methods

described below. Aggregate samples thus obtained shall be considered as representative of the lots or

sublots from which they are taken. Compliance with maximum levels laid down in Commission Regulation

(EC) No 466/2001 setting maximum levels for certain contaminants in foodstuffs shall be established on

the basis of the levels determined in the laboratory samples.

Congerer

TEF value

Congerer

TEF value

Dibenzo-p-dioxins(PCDDs )

‘Dioxin-like’ PCBsNon-ortho PCBs + Mono-

ortho PCBs

2,3,7,8-TCDD

Non-ortho PCBs

PCB 77

0,0001

1,2,3,7,8-PeCDD

PCB 81

0,0001

1,2,3,4,7,8-HxCDD

0,1

PCB 126

0,1

PCB 169

0,01

1,2,3,6,7,8-HxCDD

0,1

1,2,3,7,8,9-HxCDD

0,1

1,2,3,4,6,7,8-HpCDD

0,01

OCDD

0,0001

Dibenzofurans(PCDFs )

Mono-ortho PCBs

2,3,7,8-TCDF

0,1

PCB 105 0,0001

1,2,3,7,8-PeCDF

0,05

PCB 114 0,0005

2,3,4,7,8-PeCDF

0,5

PCB 118 0,0001

1,2,3,4,7,8-HxCDF

0,1

PCB 123 0,0001

1,2,3,6,7,8-HxCDF

0,1

PCB 156 0,0005

1,2,3,7,8,9-HxCDF

0,1

PCB 157 0,0005

2,3,4,6,7,8-HxCDF

0,1

PCB 167 0,00001

1,2,3,4,6,7,8-HpCDF

0,01

PCB 189 0,0001

1,2,3,4, 7,8,9-HpCDF

0,0001

Abbreviations used: T = tetra; Pe = penta; Hx = hexa; Hp = hepta; O = octa; CDD =

chlorodibenzodioxin; CDF = chlorodibenzofuran; CB = chlorobiphenyl.

2. General provisions

2.1. Personnel

Sampling shall be performed by an authorised qualified person as specified by the Veterinary Services.

2.2. Material to be sampled

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

2.3. Precautions to be taken

In the course of sampling and preparation of laboratory samples precautions must be taken to avoid any

changes, which would affect the content of dioxins and dioxin-like PCBs, adversely affect the analytical

determination or make the aggregate samples unrepresentative.

2.4. Incremental samples

As far as practical incremental samples shall be taken at various places distributed throughout the lot or

sublot. Departure from this procedure must be recorded in the record provided for under 2.8.

2.5. Preparation of the aggregate sample

The aggregate sample is made up by uniting all incremental samples. It shall be at least 1 kg unless not

practical, e.g. when a single package has been sampled.

2.6. Subdivision of aggregate sample in laboratory samples for enforcement, defence and referee purposes

The laboratory samples for enforcement, trade (defence) and referee purposes shall be taken from the

homogenized aggregate sample unless this conflicts with Member States' regulations on sampling. The size

of the laboratory samples for enforcement shall be sufficient to allow at least for duplicate analyses.

2.7. Packaging and transmission of aggregate and laboratory samples

Each aggregate and laboratory sample shall be placed in a clean, inert container offering adequate

protection from contamination, from loss of analytes by adsorption to the internal wall of the container and

against damage in transit. All necessary precautions shall be taken to avoid change of composition of the

aggregate and laboratory samples, which might arise during transportation or storage.

2.8. Sealing and labelling of aggregate and laboratory samples

Each sample taken for official use shall be sealed at the place of sampling and identified following the

Member States' 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.

3. Sampling plans

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

be controlled.

Number of incremental samples

In the case of milk and oils, for which a homogeneous distribution of the contaminants in question can be

assumed within a given lot, it is sufficient to take three incremental samples per lot which forms the

aggregate sample. Reference to the lot number shall be given. For other products, the minimum number of

incremental samples to be taken from the lot shall be as given in Table 1.

The aggregate sample uniting all incremental samples shall be at least 1 kg (see point 2.5). The incremental

samples shall be of similar weight. The weight of an incremental sample should be at least 100 grams. The

weight of the incremental sample is dependent on the size of the particles in the lot. Departure from this

procedure must be recorded in the record provided for under 3.8. In accordance with the provisions of

Commission Decision 97/747/EC of 27 October 1997 fixing the levels and frequencies of sampling

provided for by Council Directive 96/23/EC for the monitoring of certain substances and residues thereof in

certain animal products (1), the sample size for hen eggs is at least 12 eggs (for bulk lots as well for lots

consisting of individual packages, Tables 1 and 2).

TABLE 1

Minimum number of incremental samples to be taken from the lot

Weight of lot (in kg)

Minimum number of incremental samples to be

taken

< 50

50 to 500

> 500

If the lot consists of individual packages, then the number of packages, which shall be taken to form the

aggregate sample, is given in Table 2.

TABLE 2

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

lot

consists of individual packages

Number of packages or units in the lot

Number of packages or units to be taken

1 to 25

1 package or unit

26 to 100

about 5 %, at least 2 packages or units

> 100

about 5 %, at maximum 10 packages or units

For the purposes of these rules, and unless context otherwise Definitions.

requires -

“aggregate sample” means the combined total of all the

incremental samples taken from the lot or sublot<

“the commission” means the European Commission<

“the community” means the European Community as

established under the Treaty establishing the European Community<

“the competent authority” means the Veterinary Services

within the territory of Malta as provided under article 2 of the

Veterinary Services Act<

“incremental sample” means a quantity of material taken from

a single place in the lot or sublot<

“laboratory sample” means a representative part/quantity of

the aggregate sample intended for the laboratory<

“lot” means an identifiable quantity of food delivered at one

time and determined by the official to have common characteristics,

such as origin, variety, type of packing, packer, consignor or

markings. In the case of fish and fishery products, also the size of

fish shall be comparable.

“Member State” means a State which is a Member within the

European Community<

“sublot” means the designated part of a large lot in order to

apply the sampling method on that designated part. Each sublot

must be physically separated and identifiable<

“third country” means a State which is not a Member within

the European Community<

“Veterinary Services” means the competent authority within

the territory of Malta as established under article 2 of the Veterinary

Services Act<

SAMPLE PREPARATION AND REQUIREMENTS FOR METHODS OF ANALYSIS USED IN

OFFICIAL

CONTROL OF THE LEVELS OF DIOXINS (PCDD/PCDF) AND THE DETERMINATION OF

DIOXIN-LIKE PCBs

IN CERTAIN FOODSTUFFS

1. Objective and field of application

These requirements should be applied where foodstuffs are analysed for the official control of the levels of

dioxins (polychlorinated dibenzo-p-dioxins (PCDD) and polychlorinated dibenzofurans (PCDF)) and the

determination of dioxin-like PCBs.

Monitoring for the presence of dioxins in foodstuffs can be performed by a strategy involving a screening

method in order to select those samples with levels of dioxins and dioxin-like PCBs that are less than 30-40

% below or exceed the level of interest. The concentration of dioxins in those samples with significant

levels needs to be determined/

confirmed by a confirmatory method.

Screening methods are methods that are used to detect the presence of dioxins and dioxin-like PCBs at the

level of interest. These methods have a capacity for a high sample throughput and are used to sift large

numbers of samples for potential positives. They are specifically designed to avoid false negatives.

Confirmatory methods are methods that provide full or complementary information enabling the dioxins

and dioxin-like PCBs to be identified and quantified unequivocally at the level of interest.

2. Background

Because environmental and biological samples (including samples of foodstuffs) in general contain

complex mixtures of different dioxin congeners, the concept of Toxic Equivalency Factors (TEFs) has been

developed to facilitate risk assessment. These TEFs have been established to express concentrations of

mixtures of 2,3,7,8-substituted PCDDs

and PCDFs, and more recently, some non-ortho and mono-ortho chlorine substituted PCBs which possesses

dioxin-like activity in toxic equivalents (TEQs) of 2,3,7,8-TCDD (see Annex I).

The concentrations of the individual substances in a given sample are multiplied by their respective TEF

and subsequently summed to give the total concentration of dioxin-like compounds expressed as TEQs.

The concept of ‘upperbound’ requires using the limit of quantification for the contribution of each non-

quantified congener to the TEQ.

The concept of ‘lowerbound’ requires using zero for the contribution of each non-quantified congener to

the TEQ.

The concept of ‘mediumbound’ requires using half of the limit of quantification calculating the

contribution of each non-quantified congener to the TEQ.

3. Quality assurance requirements to be complied with for sample preparation

— Measures must be taken to avoid cross-contamination at each stage of the sampling and analysis

procedure.

— The samples must be stored and transported in glass, aluminium, polypropylene or polyethylene

containers. Traces of paper dust must be removed from the sample container. Glassware should

be rinsed with solvents previously controlled for the presence of dioxins.

— The sample storage and transportation has to be performed in a way that maintains the integrity of

the foodstuff sample.

— Insofar as relevant, finely grind and mix thoroughly each laboratory sample using a process that

has been demonstrated to achieve complete homogenisation (e.g. ground to pass a 1 mm sieve);

samples have to be dried before grinding if moisture content is too high.

— Perform a blank analysis by carrying out the entire analytical procedure omitting only the sample.

— Sample weight used for the extraction must be sufficient to fulfil the requirements with respect to

sensitivity.

— There are many satisfactory specific sample preparation procedures, which may be used for the

products under consideration. The procedures have to be validated according to internationally

accepted guidelines.

4. Requirementsfor laboratories

— Laboratories shall demonstrate the performance of a method in the range of the level of interest,

e.g. 0,5 ×, 1 × and 2 × the level of interest with an acceptable coefficient of variation for repeated

analysis. For details of acceptance criteria, see point 5.

— Limit of quantification for a confirmatory method should be in the range of about one fifth of the level

of interest, to make sure that acceptable coefficients of variations are met in the range of the level of

interest.

— Regular blank controls and spiking experiments or analysis of control samples (preferably, if

available, certified reference material) should be performed as internal quality control measures.

— Successful participation in interlaboratory studies that assess laboratory proficiency is the best way to

prove the competence in specific analyses. However successful participation in interlaboratory studies for,

e.g. soil or sewage samples, does not necessarily prove the competence also in the field of food or

feedingstuff samples,

which present lower contamination levels. Therefore, the continuous participation in interlaboratory studies

for the determination of dioxins and dioxin-like PCBs in the relevant feed/food matrices is mandatory.

— In accordance with the provisions of Directive 93/99/EEC, laboratories should be accredited by a

recognised body operating in accordance with ISO Guide 58 to ensure that they are applying analytical

quality assurance. Laboratories should be accredited following the ISO/IEC/17025:1999 standard.

5. Requirementsto be met by analytical procedure for dioxinsand dioxin-like PCBs

Basic requirements for acceptance of analytical procedures

— High sensitivity and low limits of detection. For PCDDs and PCDFs, detectable quantities have to

be in the pictogram TEQ (10-12 g) range because of extreme toxicity of some of these

compounds. PCBs are known to occur at higher levels than the PCDDs and PCDFs. For most PCB

congeners sensitivity in the nanogram (10-9 g) range is already sufficient. However, for the

measurement of the more toxic dioxin-like PCB congeners (in particular non-ortho substituted

congeners), the same sensitivity must be reached as for the PCDDs and PCDFs.

— High selectivity (specificity). A distinction is required for PCDDs, PCDFs and dioxin-like PCBs

from a multitude of other, coextracted and possibly interfering compounds present at

concentrations up to several orders of magnitude higher than those of the analytes of interest. For

gas chromatography/mass spectrometry (GC/MS) methods a differentiation among various

congeners is necessary, such as between toxic (e.g. the seventeen 2,3,7,8-substituted PCDDs and

PCDFs and dioxin-like PCBs) and other congeners. Bioassays should be able to determine TEQ

values selectively as the sum of PCDDs, PCDFs and dioxin-like PCBs.

— High accuracy (trueness and precision). The determination should provide a valid estimate of the true

concentration in a sample. High accuracy (accuracy of the measurement: the closeness of the agreement

between the result of a measurement with the true or assigned value of the measurement) is necessary to

avoid the rejection of a sample analysis result on the basis of poor reliability of the estimate of TEQ.

Accuracy is expressed as trueness (difference between the mean value measured for an analyte in a

certified material and its certified value, expressed as percentage of this value) and precision (precision is

usually calculated as a standard deviation including repeatability and reproducibility, and indicates the

closeness of agreement between the results obtained by applying the experimental procedure several times

under prescribed conditions).

Screening methods can comprise bioassays and GC/MS methods; confirmatory methods are high-resolution

gas chromatography/high resolution mass spectrometry (HRGC/HRMS) methods. Following criteria have

to be complied with on total TEQ value

False negative rate

< 1 %

Trueness

– 20 % to + 20 %

CV

< 30 %

< 15 %

Malta shall ensure that the sampling for the official control of

the levels of dioxins and furans and the determination of the levels of

dioxin-like PCBs in foodstuffs is carried out in accordance with the

methods described in Schedule I hereto.

Malta shall ensure that sample preparation and methods of

analyses used for the official control of the levels of dioxins and furans

and the determination of the levels of dioxin-like PCBs in foodstuffs

comply with the criteria described in Schedule II hereto.

Compliance of the lot or sublot with the specification

The control laboratory shall analyse the laboratory sample for enforcement in duplicate analysis in case the

obtained result of the first analysis is less than 20 % below or above the maximum level, and calculate the

mean of the results. The lot is accepted if the result of the first analysis is more than 20 % below the

maximum level or, where duplicate

analysis is necessary, if the mean conforms to the respective maximum level as laid down in Regulation

(EC) No 466/2001.

Specific requirements for GC/MS methods to be complied with for screening or confirmatory

purposes

— Addition of 13C-labelled 2,3,7,8-chlorine substituted internal PCDD/F standards (and of 13C-labelled

internal dioxin-like PCB standards, if dioxin-like PCBs have to be determined) must be carried out at the

very beginning or start of the analytical method e.g. prior to extraction in order to validate the analytical

procedure. At least one congener for each of the tetra to octa-chlorinated homologous groups for PCDD/F

(and at least one congener for each of the homologous groups for dioxin-like PCBs, if dioxin-like PCBs

have to be determined) must be added (alternatively, at least one congener for each mass spectrometric

selected ion recording function used for monitoring PCDD/F and dioxin-like PCBs). There is a clear

preference, certainly in case of confirmatory methods, of using all 17 13C-labelled 2,3,7,8-substituted

internal PCDD/F standards and all 12 13C-labelled internal dioxin-like PCB standard (if dioxin-like PCBs

have to be determined).

Relative response factors should also be determined for those congeners for which no 13C-labelled

analogue is added by using appropriate calibration solutions.

— For foodstuffs of plant origin and foodstuffs of animal origin containing less than 10 % fat, the

addition of the internal standards is mandatory prior to extraction. For foodstuffs of animal origin

containing more than 10 % fat, the internal standards can be added either before extraction or after

fat extraction. An appropriate validation of the extraction efficiency should be carried out,

depending on the stage at which internal standards are introduced and on whether results are

reported on product or fat basis.

— Prior to GC/MS analysis, 1 or 2 recovery (surrogate) standard(s) must be added.

— Control of recovery is necessary. For confirmatory methods, the recoveries of the individual

internal standards should be in the range of 60 % to 120 %. Lower or higher recoveries for

individual congeners, in particular for some hepta- and octa- chlorinated dibenzodioxins and

dibenzofurans, are acceptable on the condition that their contribution to the TEQ value does not

exceed 10 % of the total TEQ value (based on PCDD/F only). For screening methods, the

recoveries should be in the range of 30 % to 140 %.

— Separation of dioxins from interfering chlorinated compounds such as PCBs and chlorinated

diphenyl ethers should be carried out by suitable chromatographic techniques (preferably with a

florisil, alumina and/or carbon column).

— Gaschromatographic separation of isomers should be sufficient (< 25 % peak to peak between

1,2,3,4,7,8-HxCDF and 1,2,3,6,7,8-HxCDF).

— Determination should be performed according to EPA Method 1613 revision B: Tetra- through

octa-chlorinated dioxins and furans by isotope dilution HRGC/HRMS or another with equivalent

performance criteria.

— The difference between upperbound level and lower bound level should not exceed 20 % for foodstuffs

with a dioxin contamination of about 1 pg WHO-TEQ/g fat (based on PCDD/PCDF only). For foodstuffs

with a low fat content, the same requirements for contamination levels of about 1 pg WHO-TEQ/g product

have to be applied. For lower contamination levels, for example 0,50 pg WHO-TEQ/g product, the

difference between upperbound and lowerbound level may be in the range of 25 to 40 %.

Screening methodsof analysis

7.1. Introduction

Different analytical approaches can be performed using a screening method: a pure screening approach and

a quantitative approach.

Screening approach

The response of samples is compared to that of a reference sample at the level of interest. Samples with a

response less than the reference are declared negative, those with a higher response are suspected positives.

Requirements

— A blank and a reference sample(s) have to be included in each test series, which is extracted and

tested at the same time under identical conditions. The reference sample must show a clearly

elevated response in comparison to a blank.

— Extra reference samples 0,5 × and 2 × the level of interest should be included to demonstrate the

proper performance of the test in the range of interest for the control of the level of interest.

— When testing other matrices, the suitability of the reference sample(s) has to be demonstrated,

preferentially by including samples shown by HRGC/HRMS to contain a TEQ level around that of the

reference sample or else a blank spiked at this level.

— Since no internal standards can be used in bioassays, tests on repeatability are very important to

obtain information on the standard deviation within one test series. The coefficient of variation

should be below 30 %.

— For bioassays, the target compounds, possible interferences and maximum tolerable blank levels

should be defined.

Quantitative approach

The quantitative approach requires standard dilution series, duplicate or triplicate clean up and measuring

as well as blank and recovery controls. The result may be expressed as TEQ, thereby assuming that the

compounds responsible for the signal correspond to the TEQ principle. This can be performed by using

TCDD (or a dioxin/furan standard mixture) to produce a calibration curve to calculate the TEQ level in the

extract and thus in the sample. This is subsequently corrected for the TEQ level calculated for a blank

sample (to account for impurities from solvents and chemicals used), and a recovery (calculated from the

TEQ level in a quality control sample around the level of interest). It is essential to note that part of the

apparent recovery loss may be due to matrix effects and/or differences between the TEF values in the

bioassays and the official TEF values set by WHO.

7.2. Requirements for methods of analysis used for screening

— GC/MS methods of analysis and bioassays may be used for screening. For GC/MS methods the

requirements as laid down in point 6 are to be used. For cell based bioassays specific requirements

are laid down in point 7.3 and for kit-based bioassays in point 7.4.

— Information on the number of false-positive and false-negative results of a large set of samples

below and above the maximum level or action level is necessary, in comparison to the TEQ

content as determined by a confirmatory method of analysis. Actual false negative rates should be

under 1 %. The rate of false positive samples should be low enough to make the use of a screening

tool advantageous.

— Positive results have always to be confirmed by a confirmatory method of analysis (HRGC/HRMS). In

addition, samples from a wide TEQ-range should be confirmed by HRGC/HRMS (approximately 2 % to 10

% of the negative samples). Information on correspondence between bioassay and HRGC/HRMS results

should be made available.

7.3. Specific requirements for cell-based bioassays

— When performing a bioassay, every test run requires a series of reference concentrations of TCDD

or a dioxin/furan mixture (full dose-response curve with a R2 > 0,95). However, for screening

purposes an expanded low level curve for analysing low level samples could be used.

— A TCDD reference concentration (about 3 × limit of quantification) on a quality control sheet

should be used for the outcome of the bioassay over a constant time period. An alternative could

be the relative response of a reference sample in comparison to the TCDD calibration line since

the response of the cells may depend on many factors.

— Quality control (QC) charts for each type of reference material should be recorded and checked to

make sure the outcome is in accordance with the stated guidelines.

— In particular for quantitative calculations, the induction of the sample dilution used must be within

the linear portion of the response curve. Samples above the linear portion of the response curve

must be diluted and re-tested. Therefore, at least three or more dilutions at one time are

recommended to be tested.

— The percent standard deviation should not be above 15 % in a triplicate determination for each

sample dilution and not above 30 % between three independent experiments.

— The limit of detection may be set as 3 × the standard deviation of the solvent blank or of the background

response. Another approach is to apply a response that is above the background (induction factor 5 × the

solvent blank) calculated from the calibration curve of the day. The limit of quantification may be set as 5 ×

to 6 × the standard deviation of the solvent blank or of the background response or to apply a response that

is above the

background (induction factor 10 × the solvent blank) calculated from the calibration curve of the day.

7.4. Specific requirements for kit-based bioassays (1)

— Manufacturer's instructions for sample preparation and analyses have to be followed.

— Test kits should not be used after the expiration date.

— Materials or components designed for use with other kits should not be used.

— Test kits should be kept within the specified range of storage temperature and used at the specified

operating temperature.

— The limit of detection for immunoassays is determined as 3 × the standard deviation, based on 10

replicate analysis of the blank, to be divided by the slope value of the linear regression equation.

— Reference standards should be used for tests at the laboratory to make sure that the responsiveness

to the standard is within an acceptable range.

Reporting of the result

Insofar as the used analytical procedure makes it possible, the analytical results should contain the levels of

the individual PCDD/F and PCB congeners and be reported as lowerbound, upperbound and mediumbound

in order to include a maximum of information in the reporting of the results and thereby enabling the

interpretation of the

results according to specific requirements.

The report should also include the lipid content of the sample as well the method used for lipid extraction.

The recoveries of the individual internal standards must be made available in case the recoveries are

outside the range mentioned in point 6, in case the maximum level is exceeded and in other cases upon

request

Mitbug[ fl-Istamperija tal-Gvern — Printed at the Government Printing Press