Environmental and product testing for Listeria - … • 1 Marion Castle April 2013 Place co-brand...

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Microbiological testing for verification: Environmental and product testing for Listeria

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Overview

1. Value of product testing

2. Why take samples?

3. Is sampling a lottery?

4. Bacterial distribution

5. Taking samples

6. Microbiological limits

7. Sampling plan


Key steps to develop a LMP

1. Identify how Listeria can get into your

premises

2. Identify control measures

3. Implement control measures

4. Verify effectiveness of control measures

What does this mean?

Marion’s definition:

“Making sure what you think is happening is actually happening!”


Verification for Listeria control

• ingredient and raw material testing

• confirming the effectiveness of cleaning and sanitation

• environmental testing

• shelf-life testing

• product testing

• visual inspection of the effectiveness of cleaning and sanitation

• visual audit of GOP, HACCP and supporting systems

• audit of suppliers specifications and requirements

• confirm that critical limits have been achieved


Why do you conduct Listeria testing?

• Is it because of:

– A customer specification

– A regulatory requirement

– Other reasons:

• Verification of CCP

• Verification of Listeria controls

• provides assurance as to the quality and safety of

the product


Microbiological testing for Listeria

• Gives confidence that the processes are delivering

• Determines the effectiveness of the Listeria control

measures

• Gives an early warning

• Allows a response to minimise future contamination

of product and improve controls

• Ongoing - measure of the effectiveness of cleaning

and sanitation programmes

• Provides assurance as to product quality and safety

• Provides information


How to set up a programme

• Know your product(s) and process(es)

– Hazard analysis – is Listeria a hazard?

– Is there a CCP?

– Will Listeria grow?

– Is there the likelihood of post-processing

contamination?

– Is there a post-packaging treatment?

– Frequency of production

– Continuous or batch production

– Who is your consumer?


The six questions?

• Why test?

• What to test?

• Where to test?

• When to test?

• How to test?

• Who will test?

• Who will evaluate the

results?

• Who will respond to

the results?

I KEEP six honest

serving-men

(They taught me all I

knew);

Their names are What

and Why and When

And How and Where

and Who. Rudyard Kipling – The Elephant’s

Child in The Just So Stories

(1902)


What to test for – L. monocytogenes or spp

• L. monocytogenes - specific concern

• Listeria spp. – L. innocua, L. welshimerii, L.

ivanovii, etc.

– Like the same conditions / niches as L.

monocytogenes

– Not pathogens but suggest that where there is

smoke there may be fire

– May be found more frequently

– Early warning

– Useful if customers are YOPIs


ENVIRONMENTAL TESTING


Listeria testing: What do you want to know?

Is there Listeria in the

processing area?

Where is it?

Could product be

contaminated?

Are the Listeria controls working?

Listeria controls are working

Or

Yes No


Environmental testing

• If you don’t test, you

won’t find it

• Need to look in the

right place

• Need to take enough

samples

• Need to know what to

do if you find it

• Testing is about

avoiding surprises

• Aggressive, targeted

and systematic

• Flexible

• Specific to product

and process

• Ongoing

Listeria


Environmental monitoring

Listeria results

Date: 10 June 2011

Sample # Site Zone Result

1 Redline 3 Listeria not detected

2 Floor prep room 3 Listeria not detected

3 Underside prep table 3 Listeria not detected

4 Bins 3 Listeria not detected

5 Trolley wheels 3 Listeria not detected

6 Aprons, gloves 3 Listeria not detected

7 Prep table 4 Listeria not detected

8 Product conveyor 4 Listeria not detected

9 Trim table 4 Listeria not detected

10 Utensils 4 Listeria not detected

P1-P5 Product composite Listeria Detected

How many times is Listeria not-detected in the environmental samples and then the Listeria is detected in the product?


Remember

Listeria are very small

• Adhere tightly to surfaces

• Occupy nooks and crannies

• May also be present in low numbers

Photo courtesy of Richard Burrow


When is a food in danger from Listeria?

• Focus on the danger zone – The high-care / critical hygiene / RTE area after a final

CCP / micro hurdle and before an exposed RTE food

is placed in final packaging

– This includes product contact and non-product contact

surfaces.

• Collecting samples from the raw area

provides an early warning, and...

CCP Packaging


Where to sample?

• Use a floor plan , observe and mark

– what enters

– position of equipment and hygiene equipment

– and process flow including CCP and when

product packaged (for each product)

• Mark sample sites and describe clearly:

– hard to clean areas

– where Listeria may be found

– focus on food contact sites

• Take photos


Flow map – product and ingredients

Setting up an environmental sampling plan, Kate Abraham, Canadian Fishing Company, 2009


Flow map – Drain Plan



Zoning by process


Product contact surfaces

Non-product contact surfaces


Floor plan

Bulk Bag

Storage Chillier Pre-Heat

Shock Washing

and Grading

Room

Shucking and Pre-Freeze Room

Freezer

Holding Freezer

Packing Room

Carton Make-up Room

Dry Goods and Bulk Packaging Store

Heat Shock Room

Cold Store

Pre-Entry Wash Room

Staff Amenities

Cafeteria

Cartoning Room


Zones – hygiene areas Zone 2 or Zone 3/4 ?


Process flow – zones 3 and 4

Chilled Water

Bath

Spiral Freezer

Heat

ShockTable

1

Table

2

Waste Exit

Weigh and

Bag

Machine

Conveying bagged product

Glazing


Hard to reach places – require dismantling


Example programme for a small business Site Mont

h 1

M 2 M 3 M 4 M 5 M 6

Product contact surfaces

From the MPI Listeria Guidelines: Part 3 – Microbiological testing for verification of the control of Listeria monocytogenes


When to sample?

• Routine sampling

• Take environmental samples during normal operation, not during breaks

• Sample hard-to-reach areas on equipment after production (some dismantling may be required)

• Don’t clean or sanitise surfaces before sampling

• Types of sampling:

– To check cleaning –

before processing

– Drains – at end of shift

– Product contact

surfaces – 1-2hrs after

start up

– To check CCP –

during processing

– End of shift


Where to sample?

• Where there is exposed RTE-food:

– Product contact surfaces (Zone 4)

– Non-product contact surfaces (Zone 3)

• Careful selection of sites

– Areas that are difficult to clean

– Nooks and crannies

• Things can be samples

• Swabs – use appropriate techniques


What type of swab do you use?

• Advantages: – Large surface area

– Forceps apply huge

pressure

– Easy to composite

– Cheap

– Better recovery of low

numbers

Swab choice is important


PRODUCT TESTING


What is a lot?

• “Lot” or “batch” means a definitive

quantity of a commodity produced

essentially under the same conditions.

– Can be further defined as product produced

on a process line, by a shift or between major

clean-downs

• Useful for traceability and record keeping


Product testing

• Determine the frequency and number of

samples required

– However prevalence and distribution of

Listeria in a product and process is unknown

– Most sampling plans - based on customer or

regulatory requirements: product only

– In house experience / knowledge – product,

raw materials and spot checks


Bacterial distribution

• Finding bacteria in a food can be

as hard to find as Wally in a

Where’s Wally picture.



• Homogeneous

distribution

– Even distribution

– Random distribution

• Heterogeneous

distribution

– Cluster or local

distribution


Sampling

• Homogeneous

– N=5

– detected in all 5

segments

• Heterogeneous

– N=5

– was detected in 2

segments



• Sample size, n=5 x 25g

• Homogeneous

distribution

– Wally detected

• Heterogeneous

distribution

– Wally not detected

– But does this mean

that Wally is not

present?


Mechanisms of contamination

– Equipment

– People

– Water

– Aerosols

– Packaging

– Animals

– Post CCP?

=> Local/surface

contamination

(heterogeneous distribution)

– Ingredients mixed into

product

– CCP?

=> More homogeneous

distribution


Point of contamination / what happens next..

• Consider the

characteristics of the food

– inside and outside

– pH, NaCl, Aw

• Consider the process

– heat treatment, storage

• What would happen to any

surviving bacteria?

• How does this influence

the sampling plan?

Surface contamination

Sampling


A couple of examples

• Hummus

• A soft mould ripened cheese

made with pasteurised milk

For each, identify:

1. Where is the Listeria is likely to come from?

2. What will happen to the Listeria during processing?

3. What kind of Listeria distribution will there be?

4. The best way to sample the product?


Number of product samples

• Not one but...

• The minimum should

be 5 to improve the

likelihood of detection

www.mpi.govt.nz • 39 www.mpi.govt.nz • 39

BRINGING IT TOGETHER – PRODUCT

AND ENVIRONMENTAL TESTING


Sampling programme in the Listeria

Guidelines

Likelihood of

contamination

Non-product

contact surface

Product contact

surface

Product (n=5)

Zone 3 Zone 4

High >monthly >weekly >weekly

Medium >quarterly >fortnightly >fortnightly /

monthly

• Likelihood of contamination:

– High – a food that supports the growth of Listeria, and

there is a CCP and an opportunity for contamination

– Medium – a food that either doesn’t support the growth

but there is an opportunity for contamination, or no CCP

From the MPI Listeria Guidelines: Part 3 – Microbiological testing for verification of the control of Listeria monocytogenes


When to sample?

• Ideally:

– Take lots of samples

from different areas

– Initially sample weekly

– Use the information to

develop a plan

• Product:

– Min 5 product samples

– Compositing or pooling of

samples is ok, when

presence/absence

– Check the lab

assurances

• Environment:

– Ok to composite swabs

from same area

– Result not affected


What to do with the results?

• Interpret lab results!

• If results don’t make sense then ask

• Trend all results as they arrive: – E.g. excel spreadsheets

– Schematic diagram of process

• Review all data regularly – e.g. at least 6-weekly

• File results


Trend analysis

Listeria Sampling Results 0 = Negative Result 1 = LM Positive Results

Sampling Site Zone 13th Jan 20th Jan 27th Jan 3rd Feb 10th Feb 17th Feb 24th Feb 3rd March 10th Mar 17th Mar

Bulk Bag 2 0 0

Bulk Bag Pallet 2 0 0

Chiller Door Handle 2 0 0

Chiller Floor 2 0 0

Chiller Coving 2 0 0

Chiller Drain Cover 2 0 0

Chiller Drain (inside) 2 0 0

Chiller Wall 2 0 0

Chiller Hose 2 0 0

Forks of Forklift 2 0 0

Grading Room Door Handle 2 0 0

Grading Room Floor 2 0 1 0

Grading Room Coving 2 0 1 0

Grading Room Drain Cover 2 0 0

Grading Room Drain (inside) 2 0 0

Grading Room Wall 2 0 0

Grading Room Hose 2 0 0

Grader Framework 2 0 0

Grader Belt 2 0 0

Grader Belt Rollers 2 0 0

Shellstock Bin 2 0 0

Grader Room Floor Mat 2 0 0

Grading Staff Glove 2 0 0

Grading Staff Apron 2 0

Entry over Belt into HS Room 2 0

HS Room Floor 3 0 0

HS Room Coving 3 0 0

HS Room Drain Cover 3 0 0

HS RoomDrain (inside) 3 0 0

HS Room Wall 3 1 0 1

HS Room Hose 3 0 0

HS Cooker Framework 3 0 0

HS Cooker Belt 3 0 0

HS Cooker Belt Rollers 3 0 0

HS Cooker Exit Rollers 3 0 0

Entry over Belt into Open Room 3 0 0

Opening Room Floor 3 0 0

Opening Room Coving 3 1 0 0

Opening Room Drain Cover 3 0 0

Opening Room Drain (inside) 3 0 0

Opening Room Wall 3 0 0

Opening Room Hose 3 0 1

Opening Room Waste Exit Belt 3 0 0

Opening Room Table 1 Framework 3 0 0

Opening Room Table 1 Underside 3 0 0

Opening Room Table 1 Bottom Belt 3 0 0

Opening Room Table 2 Framework 3 0

Opening Room Table 2 Underside 3 0

Opening Room Table 2 Bottom Belt 3 0

Opening Room Floor Mat 3 1

Water Bath Hood 3 0

Water Bath Framework 3 0

HS Cooker Exit Belt 4 0 0 0 0

Openiing Room Cooker Exit Belt 4 0 0 0 0

Opening Room Table 1 Belt 4 0 0 0 0


Opener's Knife 4 0 0 0 0

Opening Chute 4 0 0 0 0

Opening Table Transfer Belt 4 0 0 0 0

Opening Room Belt to Water Bath 4 0 0 0

Water Bath Belt 4 0 0 0

Water Bath Exit Belt 4 0 0 0

Pre-Freezer Grading Belt 4 0 0 0


Showing the detections

Listeria Sampling Results 0 = Negative Result 1 = LM Positive Results

Sampling Site Zone 13th Jan 20th Jan 27th Jan 3rd Feb 10th Feb 17th Feb 24th Feb 3rd March 10th Mar 17th Mar

Bulk Bag 2 0 0

Bulk Bag Pallet 2 0 0

Chiller Door Handle 2 0 0

Chiller Floor 2 0 0

Chiller Coving 2 0 0

Chiller Drain Cover 2 0 0

Chiller Drain (inside) 2 0 0

Chiller Wall 2 0 0

Chiller Hose 2 0 0

Forks of Forklift 2 0 0

Grading Room Door Handle 2 0 0

Grading Room Floor 2 0 1 0

Grading Room Coving 2 0 1 0

Grading Room Drain Cover 2 0 0

Grading Room Drain (inside) 2 0 0

Grading Room Wall 2 0 0

Grading Room Hose 2 0 0

Grader Framework 2 0 0

Grader Belt 2 0 0

Grader Belt Rollers 2 0 0

Shellstock Bin 2 0 0

Grader Room Floor Mat 2 0 0

Grading Staff Glove 2 0 0

Grading Staff Apron 2 0

Entry over Belt into HS Room 2 0

HS Room Floor 3 0 0

HS Room Coving 3 0 0

HS Room Drain Cover 3 0 0

HS RoomDrain (inside) 3 0 0

HS Room Wall 3 1 0 1

HS Room Hose 3 0 0

HS Cooker Framework 3 0 0

HS Cooker Belt 3 0 0

HS Cooker Belt Rollers 3 0 0

HS Cooker Exit Rollers 3 0 0

Entry over Belt into Open Room 3 0 0

Opening Room Floor 3 0 0

Opening Room Coving 3 1 0 0

Opening Room Drain Cover 3 0 0

Opening Room Drain (inside) 3 0 0

Opening Room Wall 3 0 0

Opening Room Hose 3 0 1

Opening Room Waste Exit Belt 3 0 0

Opening Room Table 1 Framework 3 0 0

Opening Room Table 1 Underside 3 0 0

Opening Room Table 1 Bottom Belt 3 0 0

Opening Room Table 2 Framework 3 0

Opening Room Table 2 Underside 3 0

Opening Room Table 2 Bottom Belt 3 0

Opening Room Floor Mat 3 1

Water Bath Hood 3 0

Water Bath Framework 3 0

HS Cooker Exit Belt 4 0 0 0 0

Openiing Room Cooker Exit Belt 4 0 0 0 0



Opener's Knife 4 0 0 0 0

Opening Chute 4 0 0 0 0

Opening Table Transfer Belt 4 0 0 0 0

Opening Room Belt to Water Bath 4 0 0 0

Water Bath Belt 4 0 0 0

Water Bath Exit Belt 4 0 0 0

Pre-Freezer Grading Belt 4 0 0 0


Trend analysis: results

1. 13 January 2010 HS room wall

2. 27 January 2010 Opening room coving

3. 17 February 2010 Opening room floor mat

4. 24 February 2010 HS room wall

5. 3 March 2010 Grading room floor

6. 3 March 2010 Grading room coving

7. 17 March 2010 Opening room hose

8. 17 March 2010 Opening room table 2 belt


What does it show?

What does this show?

– Contamination from

raw side

– Through Heat shock

room

– Into opening room

– Onto hose?

– Onto opening table

• Potential issues:

• Personnel

movements?

• Cleaning practices?

• Hygienic design?

• Hose maintenance?

• Hose use?


Documentation

• Ensure that your programme is fit for purpose

• Record what you do?

– How you validate your listericidal process, e.g.

Cooking?

– How you check time/temperature?

– What you test?

– When you test?

– What are the results?

– What your response has been?

• Competencies and training, e.g. samplers


Testing

• Product testing is often like or a

• It is not possible to test everything

• This doesn’t mean that you shouldn’t test but that you need to be smart

• Testing is not able to provide the sole assurance that your food is safe

• Use testing with HACCP and GOP as the basis

• Testing should be used to verify or to gather information

T

e

s

t

i

n

g


Final words

• Know why you are testing?

• What you are testing?

• When you are testing?

• How you are testing/sampling?

• What you will do with the results?

• And who will test?

Remember ‘The Just So

Stories’


Useful references

• Tompkin R.B. 2002. Control of Listeria monocytogenes in the Food-Processing

Environment. Journal of Food Protection. Volume 65, Number 4, 1 April 2002 , pp. 709-725(17)

• Industry Guidelines to Prevent Contamination from Listeria monocytogenes (2010)

• Originally published as a National Pork Board/American Meat Science Association Fact Sheet.

• Authors: R. Bruce Tompkin, Armour Swift-Eckrich, Downer’s Grove IL; Dane T. Bernard, National

Food Processors Association, Washington DC; Virginia N. Scott, National Food Processors

Association, Washington DC; William H. Sveum, Campbell Soup Company, Camden NJ; Kathy

Sullivan Gombas, formerly with Kraft Foods, Inc, Washington DC – http://www.extension.org/pages/27405/industry-guidelines-to-prevent-contamination-from-listeria-monocytogenes

• R. Bruce Tompkin,1 Virginia N. Scott,“ Done T. Bernnrd,2. William H. 1999. Guidelines to Prevent.

Post-Processing. Contamination from. Listeria monocytogenes. Dairy, Food and Environmental

Sanitatio. Vol 19., No. 8., pp551-562. – http://www.listeriosisprevention.com/Guidelines.pdf

• Setting up an Environmental. Sampling Plan. Kate Abraham. Canadian Fishing Company. BC

Food Protection Association. Burnaby, April 30, 2009 – http://www.bcfpa.net/Attachments/Presentations/Setting%20up%20an%20Environmental%20Sampling%20Plan%20%28K%20Abr

aham%29%2030%20April%202009.pdf

• Listeria Management Program (NSW FA) – http://www.foodauthority.nsw.gov.au/_Documents/industry_pdf/listeria-management-program.pdf

• Dealing with Listeria in the processed meat & poultry industries Summit 2010 – http://www.foodauthority.nsw.gov.au/industry/news-publications-and-help/other-publications/#.UVlBmFfKWSo

• Processing of Seafood Code of Practice; Part 2 GOP - Part17-30 – http://www.foodsafety.govt.nz/elibrary/industry/code-practice-seafood/part-2-sections17-30.pdf

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

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