EURL Guidelines for sampling food preparation

areas and equipment for L. monocytogenes

Léna BARRE & Brigitte CARPENTIER

French Agency for food, environmental & occupational health & safety

European Union

Reference Laboratory

for Listeria

monocytogenes

Context

• RTE foods can be contaminated during processing by

subtypes of Lm which persist in the processing plants

• Sampling processing is thus necessary & mandatory* to:

detect possible Lm persistence

eliminate it

implement corrective actions

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*2073/2005, Article 5, paragraph 2:

“Samples shall be taken from processing areas and equipment used in food

production, when such sampling is necessary for ensuring that the criteria are met.

In that sampling the ISO standard 18593 shall be used as a reference method.

Context

• ISO 18593* on surface sampling methods does not give

sufficient guidance specific to Lm detection

• Great variety of sampling practices and some wrong

practices

Stress the urgent need for European guidelines

*“Microbiology of food and animal feeding stuffs -- Horizontal methods for

sampling techniques from surfaces using contact plates and swabs”

3

Context

Guidelines on sampling the food processing area & equipment for the detection of Lm

4

FBOs

WG NRLs

EURL Lm

1- Review the ISO 18593 Standard

2- Review the literature: need to add to the ISO Standard

specific guidance on sampling techniques for Lm control

3- Conduct a survey: EURL conducted enquiry to survey

the different practices in terms of environmental sampling

techniques

4- Publish the guidelines

5

Steps in the Guidelines production

1- Review the ISO 18593 Standard

2- Review the literature: need to add to the ISO Standard

specific guidance on sampling techniques for Lm control

3- Conduct a survey: EURL conducted enquiry to survey

the different practices in terms of environmental sampling

techniques

4- Publish the guidelines

6

Steps in the Guidelines production

The ISO 18593* standard does not describe:

- when sampling should be performed

- what areas should be sampled

The standard ISO 18593 does not provide all the

necessary information

* ISO 18593 : “Microbiology of food and animal feeding stuffs -- Horizontal methods for

sampling techniques from surfaces using contact plates and swabs”

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ISO 18593

1- Review the ISO 18593 Standard

2- Review the literature : need to add to the ISO Standard

specific guidance on sampling techniques for Lm control

3- Conduct a survey: EURL conducted enquiry to survey

the different practices in terms of environmental sampling

techniques

4- Publish the guidelines

8

Steps in the Guidelines production

Review of the literature ISO 18 593 FDA Guidance

document (2008)

Other references

Sampled

flat

surface

area

At least 100

cm2 preferably

about 1000cm2

Constant area as large

as possible

- 30-100 cm2

for sponging

- 10-13 cm2

for swabbing

2000-5000 cm² (Tompkin,

1999)

3716 cm2 (Mc Namara, 2007)

Up to 900 cm² (Canadian rec,

2010)

Up to 50 cm² (NSW, 2008)

Time at

which

sampling

should be

performed

After the

disinfection

contact time

to assess the

performance of

the C &D

programme

Critical Food-Contact

Surfaces:

both prior to cleanup

& no sooner than the

middle of production

Critical Non-Food-

Contact Surfaces:

at any time

After minimum 3H

production (Mc Namara,

2007)

During or at the end of

production (Tompkin, 2004)

During full production or

before equipment clean-up

(NSW, 2008)

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Review of the literature

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Review of the literature Comparison of the requirements or recommendations on how to perform sampling of

surfaces including those specifically written for Lm

Main ideas:

Recommendations found in the literature are not all the same

Few published scientific papers reported on results obtained in field

conditions (Kovacevic et al; 2009)

FBOs have great experience in sampling surfaces for Lm detection and

that they do not publish their knowhow

Launching of a European survey to know how they proceed

1- Review the ISO 18593 Standard

2- Review the literature: need to add to the ISO Standard

specific guidance on sampling techniques for Lm control

3- Conduct a survey: EURL conducted enquiry to survey

the different practices in terms of environmental sampling

techniques

4- Publish the guidelines

12

Steps in the Guidelines production

The EURL conducted a survey in 2010 on the different

practices in terms of environmental sampling techniques

Enquiry into NRLs, competent authorities and FBOs

137 respondents, from 15 EU Member States

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European survey

Scrubbing devices

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European survey

Sponges

Gauze pads Unwoven pad

Swabs

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European survey

wet

Brush & gauze pad (only in the event of an

alert, only one respondent)

+

Dry

What scrubbing device(s) do you use?

29%

20% 16%

16%

7%

5%

3% 3% 1% gauze pad

wet cotton swab only

multiple response

sponge

dry cotton swab only

?

dry and wet swabs only

other

brush

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• Several respondents declared wrong practices

– sampling only after C&D,

– sampling too small areas ...

Emphases the need for European guidelines

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European survey

• Several respondents declared wrong practices

– sampling only after C&D,

– sampling too small areas ...

Emphases the need for European guidelines

1- Review the ISO 18593 Standard

2- Review the literature: need to add to the ISO Standard

specific guidance on sampling techniques for Lm control

3- Conduct a survey: EURL conducted enquiry to survey

the different practices in terms of environmental sampling

techniques

4- Publish the guidelines

18

Steps in the Guidelines production

Steps in the Guidelines production • March 2011

– Draft 1 sent to NRLs, each NRL circulated it to operators practicing

surface sampling

• September 2011

– 80 comments from 20 reviewers, Draft 2 sent to an European

working group of 20 people (Italy, Denmark, Portugal, Spain,

France, Ireland, Estonia)

• February 2012

– 90 comments from 13 reviewers, Draft 3 sent to the working

group

• March 2012

– 37 comments from 5 reviewers

– Draft 4 sent to the working group for a last discussion at a

web/phone meeting: version 0

– 28 March: NRLs approval version 1

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Steps in the Guidelines production

• April – August 2012

version 3 which is available at:

http://www.ansespro.fr/eurl-listeria

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The Guidelines

1. SCOPE

2. NORMATIVE REFERENCES

3. CHOICE OF SAMPLING LOCATIONS

4. TIME AT WHICH SAMPLING SHALL BE PERFORMED

5. DILUENTS TO MOISTEN THE WIPE SAMPLING DEVICES

6. CULTURE MEDIA

7. APPARATUS AND GLASSWARE

8. AREA TO BE SAMPLED

9. PREPARATION OF SAMPLING DEVICES

10.SAMPLING

11.TRANSPORT

12.SAMPLE ANALYSIS

13.EXPRESSION OF RESULTS

14.REFERENCES

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http://www.ansespro.fr/eurl-listeria

Main differences: guidelines vs ISO 18593

1. SCOPE

– NOTE 2: No advice on

• sampling frequency

• number of sampling points

• validity of compositing (pooling) the samples

• necessity to rotate sampling points

they have to be chosen on a case-by-case basis, with a risk-based approach.

– NOTE 3: These guidelines are not designed to assess C&D

efficiency

2. CHOICE OF SAMPLING LOCATIONS

– A non-exhaustive list of places to choose sampling locations is

given quite similar to those of the FDA (2008) & NSW (2008)

doc.

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3. TIME AT WHICH SAMPLING SHOULD BE

PERFORMED

– Sampling should be performed • during processing

• after at least 2h of production

• or at the end of production runs

– When raw food is processed, sampling after

C&D or at the beginning of production can be

performed • Yet, this can lead to a false sense of security

• The detection of L. monocytogenes on food-contact surfaces

after C&D indicates a serious failure in C&D procedures.

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Main differences: guidelines vs ISO 18593

4. DILUENTS TO MOISTEN THE WIPE SAMPLING DEVICES

– No neutralizer when sampling during or at the end of

production except when residues of disinfectants are

expected

– Phosphate buffered diluents are not recommended

5. AREA TO BE SAMPLED

– hard-to-reach/small areas stick swabs

– large areas sponge, woven or unwoven cloth or

gauze pad • The total sampled area should be as large as possible

• It is advised to sample between 1000 cm² and 3000 cm² when the areas

are open and flat (conveyors, shelves, etc.)

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Main differences: guidelines vs ISO 18593

Main differences : guidelines vs ISO 18593

6. PREPARATION OF SAMPLING DEVICES

– No equipment which has been inside a microbiology

laboratory should be taken into a food production area

due to the risks of introducing contamination

– Operators should ensure that no item used for sampling

is left in the production area. For this purpose, counting

these items before and after sampling is recommended.

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Main differences : guidelines vs ISO 18593

7. TRANSPORT, STORAGE, STARTING ANALYSIS

– Several reviewers asked for length of time longer than

24h before sample analysis (48h, 72h)

– Decision: Examine the samples ASAP, preferably not

later than 24h after receipt at the lab & in any case not

later than 36h after sampling (ISO 7218).

8. SAMPLE ANALYSIS

– ½ Fraser broth in the sampling device,

EN ISO 11290-1 or any alternative validated method

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27

The shadows on the wall do not

make up reality at all

Next steps • Analysis of the 2nd part of the survey on the

sample analysis, review of the literature and

decision whether there is a need for specific

recommendations, not included in the

EN ISO 11290-1&2 Standards

• Proposal : an experimental study to assess – The impact of using a neutralizer on the probability to detect Lm

– The best diluent/neutralizer to avoid loss of culturability of

stressed Lm cells

– The best wiping device : sponge, woven on unwoven cloth,

gauze pad

– Etc.

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IN COLLABORATION WITH

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SPAIN

J. Canet Noguera

A. Español Pueyo

J. Lago

J. Pardos Bosch

J. Sanchez Hernandez

PORTUGAL

H. da Silva Mateus Fernandes Guedes

A. L. Ferreira Tavares

S. Orfão Ferraz

C. M. Pires Gomes

M. Sol

M. M. Tenreiro dos Santos Monteiro Saraiva

FRANCE

C. Dufour

T. Grégori

P. Leglise

N. Sanchez

V. Stahl

ITALY

S. Barbuti

DENMARK

L. Gram

IRELAND

B. Hickey

ESTONIA

J. Toomas Kramarenko

UE DG-SANCO

References

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ISO 18593. Microbiology of food and animal feeding stuffs -- Horizontal methods for sampling

techniques from surfaces using contact plates and swabs.

ISO 7218 Microbiology of food and animal feeding stuffs — General requirements and

guidance for microbiological examinations

FDA. 2008. Guidance for Industry: Control of Listeria monocytogenes in Refrigerated or

Frozen Ready-To-Eat Foods; Draft Guidance. U.S. Food and Drug Administration,

Department of Health and Human Services

http://www.fda.gov/Food/GuidanceComplianceRegulatoryInformation/GuidanceDocuments/F

oodProcessingHACCP/ucm073110.htm, accessed 1 April 2010.

NSW. 2008. Food Authority for meat processors and retail meat licensees. Listeria

Management Program NSW/FA/FI034/0809.

http://www.foodauthority.nsw.gov.au/_Documents/industry_pdf/listeria-management-

program.pdf accessed 27 January 2011:40 pp.

http://www.ansespro.fr/eurl-listeria

THANK YOU FOR YOUR

ATTENTION

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