ANNEX I
Technical specifications in accordance with Article 2
1. Sampling frame
A minimum number of pigs, kept during at least the preceding three months in the Member State, shall be ad random sampled in accordance with Table 1.
Table 1
Minimum sample size
Number of pigs present in the population
Minimum sample size ( 1 )
> 20 000 000
2 400
10 to 20 000 000
1 067
2 to 10 000 000
600
< 2 000 000
384
Member States shall take a 10 % extra number of samples, to be analyzed in case some samples would be excluded from the study for various reasons.
Samplings shall be stratified by month to ensure to cover the different seasons.
Sampling shall be stratified by slaughterhouses that participate and proportional to slaughterhouse capacity. Each Member State shall rank all slaughterhouses according to their fattening pigs throughput in the previous year. Thus, each Member State shall identify those plants that accounted for at least 80 % of all slaughtered fattening pigs.
The total number of pigs and carcases to be sampled in each of the slaughterhouses included in the study shall be estimated by multiplying the sample size (e.g. 2 400) by the proportion of fattening pigs processed in the previous year. For example, if one slaughterhouse accounted for 25 % of fattening pigs slaughtered in the selected slaughterhouses (those representing at least 80 % of all fattening pigs slaughtered in the Member State), then (2 400 × 0,25) 600 pigs shall be sampled. These shall be evenly divided so that 50 pigs were sampled in every month, for 12 months. A further example is shown in Table 2.
Naturally, if a slaughterhouse is no longer in production, if a new facility has been opened or there is predicted to be a significant change in plant throughput during the survey, then the estimated throughput shall be adjusted accordingly.
Table 2
Weighing of slaughterhouses for the purpose of allocating the number of fattening pigs to be sampled from each slaughterhouse; calculation of sampled animals per slaughterhouse
Slaughterhouse ID
Number of fattening pigs processed previous year
Percent of total slaughter included in the study
Number of samples per slaughterhouse
Samples per month
(/12)
AXD
88 000
17,6
0,176 × 2 400 = 422,4
422,4:12 = 36
SVH
25 000
5,0
TPB
75 000
15,0
MLG
100 000
20,0
GHT
212 000
42,4
Total
500 000 ( 2 )
100,0
For each slaughterhouse each month, a number between 1 and 31 shall be selected at random. If the randomly selected number is a slaughtering day, for that month, then that day is selected for sampling. If not, then a new number is selected randomly. This process is performed once a month and repeated so many times as there are samples to be collected at the slaughterhouse. For example, in the slaughterhouse AXD the process shall be repeated at least 36 times to select at least 36 working days randomly. Naturally, it might be more than one carcase to be sampled on the same day.
As the number of animals slaughtered on a specific day may vary enormously, the random selection of the individual animal shall take place at the slaughterhouse at the day randomly selected for sampling. The given day, the total number of animals is known, and the personnel of the slaughterhouse shall then randomly select a carcase or carcases using the randomisation sheet which has been provided to them and which has been generated using a maximum that exceeds the highest possible number of fattening pigs slaughtered on any given day in any slaughterhouse in the Member State.
A randomisation table may then look as shown in Table 3.
Table 3
Randomisation table
Slaughterhouse
Day of the month
Identity of carcase ( 3 )
AXD
19
5
4
2
12
124
12
2
8
59
The following animals shall be excluded from the baseline study:
—
animals with a live weight of less than 50 kg or more than 170 kg,
—
animals that have undergone emergency slaughter,
—
any carcase that is totally condemned.
2. Samples
2.1. Sampling in general
The following samples shall be collected:
—
the aggregate of ileocaecal lymph nodes or at least five individual ileocaecal lymph nodes of all selected pigs. If possible, at least 25 grams of lymph nodes without fat or connective tissues shall be collected,
—
a sponge swabbed at four sites in accordance with paragraph 2(3), per carcase, from a total of at least 384 pigs, randomly selected from the selected pigs. The sponge sampling method shall be used in accordance with the most recent edition of standard ISO 17604. This sampling shall be carried out in Belgium, the Czech Republic, Denmark, France, Ireland, Cyprus, Latvia, Lithuania, Austria, Poland, Slovenia, Sweden and the United Kingdom,
—
a muscle sample for serology on meat juice or blood (if equivalent to the method on meat juice) from all selected pigs. Sufficient neck or diaphragm muscle shall be taken to yield enough meat juice to allow a portion to be frozen and stored for later comparative studies. This sampling shall be carried out in Denmark, Germany, France, Ireland, Cyprus, Lithuania, the Netherlands, Slovenia, Sweden and the United Kingdom.
Records shall be kept at the slaughterhouse on the muscle which is sampled, time and date of sampling of each sample and the time and date and name of the courier that takes delivery of the samples.
2.2. Details on sampling of ileocaecal lymph nodes
The mesenterium between the caecum and the part of the ileum that is closest to the caecum shall be torn and the ileocaecal lymph nodes are presented at the surface of the torn-open area. Without a knife, but with gloved fingers, the lymph nodes shall be bluntly ‘harvested’ from such opened mesenterium if individual lymph nodes are collected. The lymph nodes or the aggregate shall be placed in a plastic bag which is marked with date, time, slaughterhouse identification and sample identification code.
2.3. Details on carcase sampling by surface swabs-sampling
Sampling of the carcase shall be performed after evisceration and before chilling. A surface of about 100 cm 2 per site shall be swabbed using one single abrasive sponge for all the following sites as indicated and numbered below in accordance with Annex A of standard ISO 17604:
—
hind limb, medial (9),
—
abdomen, lateral (belly, 3),
—
mid-dorsal region (mid-back, 4),
—
jowl (7).
Two sites shall be swabbed with one side of the sponge, which shall then be turned over for the remaining two sites, and a scrubbing action shall be used. Enough pressure shall be used to push the lower part of the carcase slightly (2 to 5 mm) away from the sampler. The sponge shall be wiped over each sampling site for a total of approximately 10 times in the vertical and 10 times in the horizontal direction. If templates are used, precautions shall be taken to avoid cross-contamination between carcases.
The sample shall be kept at max. 7 °C during storage and transportation. The plastic bag is marked with the date, time, slaughterhouse identification and sample identification code.
3. Transport
Samples shall be sent within 36 hours by fast mail or courier and shall reach the laboratory no later than 72 hours after sampling. Samples arriving later than within 72 hours after sampling shall be discarded unless analysis is initiated within 96 hours after sampling and the cold chain was not interrupted.
4. Analysis of samples
Analysis and serotyping shall take place at the National Reference Laboratory (NRL). In case that the NRL does not have the capacity to perform all analyses or if it is not the laboratory that performs detection routinely, the competent authorities may decide to designate a limited number of other laboratories involved in official control of Salmonella to perform the analyses. These laboratories should have proven experience of using the required detection method and have a quality assurance system complying with ISO standard 17025 and be submitted to the supervision of the NRL.
At the laboratory, samples shall be kept refrigerated until bacteriological examination, which shall be carried out within 24 hours after receipt and so that analysis is initiated no later than 96 hours after the sample was collected.
The muscle sample for serology shall be kept frozen until analysis, which shall be carried out immediately after thawing.
4.1. Sample preparation for bacteriology
Lymph nodes shall be surface de-contaminated before analysis by dipping into absolute alcohol and drying by air.
All lymph nodes shall be pooled and closed in a plastic bag and banged with a hammer or so on the plastic bag smashing the lymph nodes.
The homogenised lymph nodes shall be weighed and placed in a sterile container with pre-warmed buffered peptone water (BPW) in dilution 1:10. Containers shall be incubated for a total of (18 ± 2) hours at (37 ± 1) °C.
Regarding swabs sample, at the laboratory, 100 ml of BPW shall be added for pre-enrichment. The sample shall be incubated at 37 °C overnight and examined for Salmonella using the modified semi-solid Rappaport-Vassiladis medium (MRSV) method (draft Annex D of the ISO 6579:2002(E).
4.2. Detection method for bacteriology
The method recommended by the Community Reference Laboratory (CRL) for Salmonella in Bilthoven, the Netherlands, shall be used. This method is described in the current version of draft Annex D of ISO 6579:2002: ‘Detection of Salmonella spp. in animal faeces and in samples of the primary production stage.’ In this method, MSRV shall be used as the single selective enrichment medium.
4.3. Serotyping
All strains isolated and confirmed as Salmonella spp. shall be serotyped according to the Kaufmann-White scheme.
For quality assurance, 16 typable strains and 16 non-typable isolates shall be sent to the CRL. If less strains have been isolated, all shall be sent.
4.4. Phage typing
In case isolates of Salmonella serovar typhimurium and Salmonella serovar enteritidis are phage typed (optional), the methods described by WHO reference centre for phage typing of Salmonella of the Health Protection Agency (HPA), Colindale, United Kingdom, shall be used.
4.5. Testing of anti-microbial susceptibility
In case of testing for anti-microbial susceptibility (optional), a validated and controlled method for testing shall be used, such as those recommended by the National Committee for Clinical Laboratory Standards (NCCLS, since 1 January 2005: ‘Clinical and Laboratory Standards Institute’ — CLSI).
Both agar diffusion and broth dilution methods are acceptable. Results shall be reported both as quantitative data (MIC for dilution methods and inhibition zone diameter for diffusion methods) and as qualitative data (proportion resistant isolates). Qualitative data shall be based on interpretation according to epidemiological cut-off values presented by the European Committee on Antimicrobial Susceptibility Testing (EUCAST) at: http://www.eucast.org
The isolates shall be tested for the susceptibility to the antimicrobial substances listed below:
—
Ampicillin or Amoxicillin,
—
Tetracycline,
—
Chloramphenicol,
—
Florfenicol,
—
Nalidixic acid,
—
Ciprofloxacin (preferably) or Enrofloxacin,
—
Sulphonamide (preferably Sulfametoxazole),
—
Sulphonamide/Trimethoprim or Trimethoprim,
—
Gentamicin,
—
Streptomycin,
—
Kanamycin (preferably) or Neomycin,
—
third generation Cephalosporin, (preferably Cefotaxime),
—
Colistin (optional).
Before initiation of the study Member States are encouraged to organise training for the involved parties.
5. Records and sample storage
Records of bacteriology shall be kept on all samples processed in a format like or comparable to the example given in Table 4.
All strains isolated shall be stored at the NRLs of the different Member States as long as it ensures integrity of the strains for a minimum of five years.
All samples of meat juice for serology shall be stored frozen for two years.
Table 4
Example of records to be taken on all processed samples
Sample
Receipt
Analysis
Sample ID + type ( 4 )
Slaughterhouse ID
Name
Date
Time
Name
Date
Time
Positive or Negative
Serovar
Phagetype
Antibiogram
Storage ID
1 S
EU012
PW
3-10-06
12:00
AB
3-10
14:00
Neg
2 L
EU023
PW
4-10
12:30
AB
4-10
14:00
Pos
Typh
DT104
ASTSu
(IDnr)
3 L
EU083
PW
8-10
16:30
AB
9-10
9:00
Pos
Agona
n.a. ( 5 )
ASTE
(IDnr)
6. Reporting from Member States
The competent authority responsible for the preparation of the yearly national report on the monitoring of Salmonella in animals pursuant to Article 9 of Directive 2003/99/EC shall collect and evaluate the results and report to the Commission.
Reports shall be made including at least the following information:
6.1. Overall description on the implementation of the programme
—
description of the population under study stratified according to slaughterhouses capacity,
—
description of randomisation procedure, including notification system,
—
sample size calculated,
—
details of authorities and laboratories involved in sampling/testing/typing,
—
overall results of the study (samples analysed by bacteriology and serology, number of positive, serovar, phage type and antibiotic resistance testing).
6.2. Complete data on each animal sampled and corresponding tests results:
The Member States shall submit the results of the investigation in the form of raw data using a data dictionary and data collection forms provided by the Commission. This dictionary and forms shall be established by the Commission:
—
reference of the slaughterhouse,
—
capacity of the slaughterhouse,
—
date and time of sampling,
—
reference of the samples (e.g. number),
—
type of samples taken: lymph nodes, carcase swab,
—
date of shipment to the laboratory.
The following information shall be collected in Member States for each sample sent to the laboratory:
—
ID of the laboratory (in case several laboratories are involved),
—
means of transport of samples,
—
date of reception by the laboratory,
—
when testing lymph nodes, weight of the specimen,
—
result for the individual sample tested: ‘negative’ or in case positive for Salmonella spp., also the results of serotyping ‘
Salmonella serovar’ or ‘untypable’,
—
results for strains subject to antimicrobial susceptibility testing and/or phagetyping results.
( 1 ) Based on an infinite population (> 100 000 per year), an estimated prevalence of 50 %, a confidence level of 95 % and a accuracy of 2, 3, 4 and 5 % respectively.
( 2 ) This number should represent at least 80 % of slaughtered fattening pigs in a Member State.
( 3 ) i.e. the fifth carcase to be processed on the 19th day of that month should be sampled for the survey.
( 4 ) Type of sample: L = lymph nodes, S = swab, MJ = meat juice.
( 5 ) n.a. = not applicable (phage typing is only done after Salmonella typhimurium and Salmonella enteritidis isolation).