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Summary of Results
External Quality Assessment of Food Microbiology
Shellfish Scheme
Distribution Number:
SF049
Sample Numbers:
SF0106 and SF0107
Distribution Date:
November 2014
Results Due:
05 December 2014
Report Date:
18 December 2014
Samples prepared and QC
tested by:
Morolake Adedeji
Stephanie Foster
Thamayanthy Ramesh
Aneta Stranc
Anitha Tallam
Data Analysed by:
Manchari Rajkumar
Nita Patel
Report Compiled by:
Manchari Rajkumar
Nita Patel
Authorised by:
Nita Patel
This report must not be reproduced without permission of the organisers.
Public Health England
Food and Environmental Proficiency Testing Unit (FEPTU)
61 Colindale Avenue
London
NW9 5EQ
Tel:
+44 (0)20 8327 7119
Fax:
+44 (0)20 8200 8264
Email: foodeqa@phe.gov.uk
The data in FEPTU reports is confidential
Page 1 of 11
Printed at 7:23 on Friday, 19 December, 2014
This Scheme provides external quality assessment samples for laboratories that examine raw bivalve molluscs from harvesting
sites in accordance with Regulation (EC) No. 854/2004 and from the production chain between harvest and consumption, in
accordance with Regulation (EC) 2073/2005 and subsequent amendments.
The Scheme is organised in collaboration with the Centre for Environment, Fisheries and Aquaculture Science (Cefas),
Weymouth, United Kingdom (UK). Articles 32 and 33 of Commission Regulation (EC) No. 882/2004 defines the roles of the
European Union Reference Laboratories (EURL) and National Reference Laboratories (NRL). These roles include
responsibility for organising comparative testing of methods.
The EU reference method for enumeration of E. coli in raw bivalve molluscs is ISO 16649-3, Microbiology of food and animal
feeding stuffs - Horizontal method for the enumeration of β-glucuronidase-positive Escherichia coli Part 3: Most probable
number technique using 5-bromo-4-chloro-3-indolyl-β-D-glucuronide.
In 2011 the Standing Committee on Food Chain and Animal Health (SCoFCAH) approved the use of two alternative methods
for the enumeration of E. coli. These are Enumeration of Escherichia coli in live bivalve molluscan shellfish by the direct
impedance technique using the BacTrac 4300 series analyser and Enumeration of Escherichia coli in bivalve molluscan
shellfish by the colony-count technique. Protocols for the application of these methods are available for download at
www.eurlcefas.org
If you require further information on the scheme please refer to:
https://www.gov.uk/government/publications/food-and-water-proficiency-testing-schemes-scheme-guide
Scheme Guide:
For more specific information about results assessments, scoring systems, statistics, and guidance on analysing your results
for the proficiency testing samples please refer to:
Guide to Scoring system and statistics:
https://www.gov.uk/government/publications/food-and-water-proficiency-testing-schemes-scoring-systems-and-statistics
FEPTU Quality Control: To demonstrate stability of the sample, a minimum of ten LENTICULE® discs, selected randomly from
a batch, are examined throughout the distribution period for E. coli enumeration and for Salmonella detection.
FEPTU results are determined using methods based on ISO methods and are included in the 'intended results' letters which
provide guidance for participants regarding the assigned values.
Intended results letters are posted on the website immediately after every distribution; electronic notification of their availability
is sent to all participants.
If you experience difficulties with any of the examinations please refer to section 17.0 of the Scheme Guide
https://www.gov.uk/government/publications/food-and-water-proficiency-testing-schemes-scheme-guide
All participants are reminded that reporting an incorrect or incomplete result or identification of pathogens from food samples
could have serious public health implications. Similarly, the levels of micro-organisms reported in the sample may affect the
subsequent outcome for the product.
Reporting an incorrect result for the Escherichia coli most probable number (MPN) may affect the classification of the
harvesting area and the subsequent treatment of the live bivalve molluscs.
Incorrect reporting of results for Salmonella may affect the subsequent outcome for the product and could have serious public
health implications
Participants are reminded that the purpose of scoring is to draw attention to incorrect or outlying results. Participants
who report outlying results for enumerations on single occasions only should not be alarmed, although they should
still assess the reason(s) for the outlying result. The results, as summarised in the performance assessment sheet
included in this report, provide a more effective indication of on-going problems with food microbiology examinations.
Please contact FEPTU or Cefas staff for advice and information:
Repeat samples
Carmen Gomes or Kermin Daruwalla
Data Analysis
Manchari Rajkumar or Nita Patel
Microbiological advice
Nita Patel or Morolake Adedeji
General comments and complaints
Nita Patel or Morolake Adedeji
Scheme consultants
Dr. Rachel Hartnell
Scheme Co-ordinator
Nita Patel
Tel:
Fax:
Email:
+44 (0)20 8327 7119
+44 (0)20 8200 8264
foodeqa@phe.gov.uk
Tel:
+44 (0)1305 206 707
Email: rachel.hartnell@cefas.co.uk
Accreditation: PHE Shellfish EQA Scheme is accredited by the United Kingdom Accreditation Service (UKAS) to ISO/IEC
Guide 17043:2010
0006
The data in FEPTU reports is confidential
Page 2 of 11
Printed at 7:23 on Friday, 19 December, 2014
Sample: SF0106
Description: Raw shellfish from a new shellfish bed
Contents:
Escherichia coli (10³-10⁴) (wild type strain), Salmonella Liverpool 1,3,19:d:e,n,z₁₅ (10²) (wild type strain), Klebsiella
oxytoca (10⁴) (wild type strain), Micrococcus sp. (10³) (wild type strain)
All levels are presented as colony forming units (cfu) per ml reconstituted sample unless otherwise stated
* MPN per 100ml reconstituted sample
Expected Results:
Examination
Expected Result
Your Result
Replicate 1
Replicate 2
PHE Score
Not Examined
E.coli (MPN)
2.1x10³ - 5.0x10⁴ per 100g
Salmonella
Detected in 25g
spp.
Comments:
Comments:
E.coli MPN values reported are summarised in Fig.1
E. coli
Total participants reporting duplicate results for E.coli MPN
85
Participants reporting a single MPN result only
0
Participants reporting MPN results within the expected range for both replicates
79
Participants reporting MPN results outside expected range for both replicates
2
Participants reporting MPN result outside expected range for one replicate only
4
Participants reporting tube combination inconsistent with MPN reported
9
Participants reporting censored values for one replicate
2
Participants reporting censored values for both replicates
1
Assigned value (participants' median MPN result )
1.0x10⁴ per 100 g
Participants' mean MPN result
1.2x10⁴ per 100 g
Standard deviation (SD) of participants' results
0.32 log₁₀ unit per 100g
FEPTU QC median MPN result
8.6x10³ per 100 g
Salmonella spp.
Total participants reporting for Salmonella spp.
77
Total participants reporting the presence of Salmonella spp.
76 (99%)
Total sent sample
90
Non-returns
2
Not examined
2
The data in FEPTU reports is confidential
Page 3 of 11
Printed at 7:23 on Friday, 19 December, 2014
Sample: SF0107
Description: Raw shellfish from a new shellfish bed
Contents:
Salmonella Wentworth 11:z₁₀:1,2 (40) (wild type strain), Aeromonas hydrophila (<10) (wild type strain), Hafnia alvei
(10³) (wild type strain)
All levels are presented as colony forming units (cfu) per ml reconstituted sample unless otherwise stated
* MPN per 100ml reconstituted sample
Expected Results:
Examination
Expected Result
Your Result
Replicate 1
Replicate 2
PHE Score
Not Examined
E.coli (MPN)
<18 per 100g
Salmonella
Detected in 25g
spp.
Comments:
Comments:
E.coli MPN values reported are summarised in Fig.2
E. coli
Total participants reporting duplicate results for E.coli MPN
83
Participants reporting a single MPN result only
0
Total participants reporting correctly the absence of E.coli
82
Total participants reporting incorrectly the presence of E.coli
1
Salmonella spp.
Total participants reporting for Salmonella spp.
77
Total participants reporting the presence of Salmonella spp.
77 (100%)
Total sent sample
90
Non-returns
2
Not examined
2
The data in FEPTU reports is confidential
Page 4 of 11
Printed at 7:23 on Friday, 19 December, 2014
Performance Assessment Sheet
Participants are reminded that to take advantage of the performance assessment overtime tool provided in the
reports they need to take part in more than one distribution a year.
Performance assessments are designed to identify laboratories with on -going problems with their examinations
and are undertaken after every distribution. Scores are allocated to results reported for every sample to help
assess participants' performance.
Cumulative scores are calculated for every participant, for all examination types, for the current and previous two
distributions. Participants' cumulative scores for each of the examination types are compared with the maximum
possible scores after every distribution.
Your laboratory performed 6 examinations for the last 3 distributions.
Distribution
Sample
E.coli score
Your % per
distribution
Salmonella sp. score
Your % per
distribution
SF0106
SF049
SF0107
SF0104
SF048
SF0105
SF0102
SF047
SF0103
Total maximum possible score
Ecoli Performance Assessment for Distributions
SF049,SF048,SF047
Salmonella Performance Assessment for Distributions
SF049,SF048,SF047
80
60
70
50
Number of participants
30
20
50
40
30
20
10
Percentage achieved of max possible
score for stipulated distributions
100
90-99
80-89
70-79
60-69
50-59
40-49
30-39
20-29
10-19
0
0
100
90-99
80-89
70-79
60-69
50-59
40-49
30-39
20-29
10-19
1-9
10
0
0
1-9
Number of participants
60
40
Percentage achieved of max possible
score for stipulated distributions
Performance Assessment Comment:
Laboratories that achieve less than 70% of the maximum possible score are likely to be experiencing significant
problems with their examinations and are advised to
a) refer to the relevant sample reports for specific comments
b) refer to the website guidance documents:
https://www.gov.uk/government/collections/external-quality-assessment-eqa-and-proficiency-testing-pt-for-food-water-and-e
nvironmental-microbiology
c) contact the organisers for advice.
The data in FEPTU reports is confidential
Page 5 of 11
Printed at 7:23 on Friday, 19 December, 2014
MPN per 100g
121
124
145
166
175
Fig. 1: SF0106 MPN Results
352
395
403
413
421
443
463
532
551
578
583
Key:
651
Î
SF0106 Replicate 1
653
655
657
666
668
684
698
¢
703
SF0106 Replicate 2
710
718
719
726
744
Printed at 7:23 on Friday, 19 December, 2014
Page 6 of 11
1,000,000
336
Laboratory Identification Number
329
Participants' Median MPN + 4 SD 112,200
115
100,000
226
Participants' Median MPN + 2.68 SD 49,980
97
The data in FEPTU reports is confidential
Participants' Median MPN 10,200
67
10,000
183
Participants' Median MPN - 2.68 SD 2,082
9
Participants' Median MPN - 4 SD 927
14
1,000
100
0
7
243
252
270
271
596
605
644
649
652
701
MPN per 100g
757
758
759
1118
Fig. 1 (cont'd): SF0106 MPN Results
1563
1564
1571
1593
1719
1769
1798
1817
Laboratory Identification Number
1527
1819
1886
1891
1892
Key:
2150
2152
Î
2154
SF0106 Replicate 1
2155
2156
x1
x2
x3
x4
¢
SF0106 Replicate 2
x6
x7
x8
x10
x9
Printed at 7:23 on Friday, 19 December, 2014
Page 7 of 11
1,000,000
1502
Participants' Median MPN + 4 SD 112,200
756
100,000
1501
Participants' Median MPN + 2.68 SD 49,980
754
The data in FEPTU reports is confidential
Participants' Median MPN 10,200
753
10,000
1160
Participants' Median MPN - 2.68 SD 2,082
752
Participants' Median MPN - 4 SD 927
751
1,000
100
749
750
1237
1487
1498
1936
2118
x5
Fig. 2: SF0107 MPN Results
No Data For Graph
Key:
Î
SF0107 Replicate 1
¢
SF0107 Replicate 2
The data in FEPTU reports is confidential
Page 8 of 11
Printed at 7:23 on Friday, 19 December, 2014
Fig. 2 (cont'd): SF0107 MPN Results
No Data For Graph
Key:
Î
SF0107 Replicate 1
¢
SF0107 Replicate 2
The data in FEPTU reports is confidential
Page 9 of 11
Printed at 7:23 on Friday, 19 December, 2014
The data in FEPTU reports is confidential
Page 10 of 11
Printed at 7:23 on Friday, 19 December, 2014
The data in FEPTU reports is confidential
Page 11 of 11
Printed at 7:23 on Friday, 19 December, 2014