How Clean is Clean : Does it Matter ?
Prof Chris Griffith
Technical Director Von Holy Consulting
Emeritus Professor Cardiff School of Health Sciences
Copyright © Prof Chris Griffith, UWIC 2009
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Contents
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Cleaning , Soil and Disinfection
Allergens , biofilms and food safety
Possibilities after cleaning
Testing surface cleanliness
How clean is clean ?
Surface Testing and End product testing
Copyright © Prof Chris Griffith, UWIC 2006
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Cleaning
Cleaning
• Removal of soil
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Soil
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Matter out of place
Organic soil –carbohydrates,proteins,lipids
Mineral salts
Other chemical soils-lubricants , metal
oxides
• Associated microorganisms
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Cleaning
Cleaning
• Removal of soil
Disinfection
• Destruction or removal of microorganisms
Aim: to reduce to an acceptable level - little
or no risk
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Why is cleaning important ?
• Food Safety --–chemical and microbiological l
• Chemical residues -potential allergen
contamination ,contribute to biofilms
• Residual microorganisms increase the risk of
foodborne disease
• Residual moisture increases chances of
biofilm formation, microbial survival and
transfer
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Food Allergies
• Allergens
– Normally proteins
– Cause an IgE related immune response
– Food often more than 1 protein
• Most reactions mild BUT anaphylaxis
• Only very small amounts needed
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How Clean is Clean: Allergens
Allergen Clean
• Clean to a level that removes residual
allergenic protein from the product zone
and adjacent areas to prevent cross
contamination to subsequent product
runs
• Links to quantity in food and quantity to
trigger a reaction
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What is a Biofilm?
“Aggregation of microorganisms and their
associated extracellular substances, actively
attached to, growing and multiplying on a
surface”
“Complex consortium of microorganisms
enmeshed within an extracellular matrix”
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Residual Microorganisms in the Food
Production Environment and Food
Safety/Quality
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Surface Counts and Product Contamination
• 4 yr Listeria monocytogenes study –JFP
2008
• 46% product isolates and 41% surface
• Persistent strains even after cleaning /dis
infection –2 year period
• Strains on gloves /floors
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After closure of dairy A , approximately 100
additional environmental and product samples
were collected from the dairy's processing
facility and adjacent retail store on January 2,
2008.
One environmental swab from a floor drain in
the finished product area, one skim milk sample,
and seven flavored milk samples tested positive
for L. monocytogenes and matched the outbreak
strain by PFGE using the two restriction
enzymes.
Outbreak of Listeria monocytogenes Infections Associated with Pasteurized
Milk from a Local Dairy - Massachusetts, 2007
MMWR Weekly, 10th October 2008 / 57(40);1097-1100
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The dairy’s records indicated the pasteuriser
met standards for time/temperature and flow
rate . They did not have an environmental
monitoring programme . Contamination with the
outbreak strain was found in close proximity to
areas where hoses were used to clean
equipment The milk plant was closed due to the
financial burden
Outbreak of Listeria monocytogenes Infections Associated with Pasteurized
Milk from a Local Dairy - Massachusetts, 2007
MMWR Weekly, 10th October 2008 / 57(40);1097-1100
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Lm detected in 70(3.5%)env swabs and 16(7.4%
) product from Swiss sandwich plant. Of the 86
isolates 93% were serotype 1/2a with 6 genetic
profiles . 78% belonged to one genotype found
on slicers , conveyors, tables,bread feeding
machine salmon, and egg sandwiches . These
strains persisted for more than 9 months on
slicers and conveyors . Revision of cleaning
programmes solved the problem . Emphasizes
impt of env monitoring to identify potential
contamination problems and as early warning
Food Control April 2010
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Examples of Lm Plant Persistence by Product
Cheese
11month – 7 years
Fish
months – 4 years
Meat
months – 5 years
Poultry
12 years
Tompkin Journal of Food Protection
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Maple Leaf Plant Reopens after Listeria
Outbreak
• 20 Deaths and estimated Cost of $20 m –Aug /Sept 2008
• CEO said the slicing equipment at the plant will
now be subject to stricter cleaning and testing , including
disassembling
The CEO said the machines had been cleaned on a daily,
weekly and monthly basis but it wasn’t until the
machines were disassembled that they found the area
where the bacteria had become embedded
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Salmonelllosis
Salmonella Enteritidis infections associated
with a contaminated immersion blender, New
Hampshire, 2009
This outbreak of Salmonella Enteritidis was
caused by a Salmonella-contaminated
immersion blender. A malfunctioning blender
shaft seal is suspected to have resulted in
poor cleaning leading to contamination of the
products prepared using the blender.
Copyright © Prof Chris Griffith, 2009
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A BIG Case of Recontamination!
USA 1994, 224,000 customers suffered
Salmonella food poisoning from eating
ice-cream due to poor cleaning of bulk
transporters.
Tolley January, 1998
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Surface Cleanliness and Ice Cream
Contamination
• Enterobacteriaceae should be largely
destroyed by Pasteurisation
• Studies in UK 15% Ireland 6.5 % :
Spain 47% were unsatisfactory with some
counts in excess of 106
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Characteristics of 4 Most Important
Emerging Pathogens
ID
X Cont
Severity
STEC
Low
Yes
Lm
Low *
Yes
Severe
Campylobacter
Low
Yes
Moderate
Norovirus
Low
Yes
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Severe
Mild
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Importance of the food environment
“if an organism is found in the food
environment there is a 70% chance of it
getting into the food.”
IAFP Rome 2007
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Why cleaning is important
• Food Safety --–microbiological and chemical
• Shelf life
• Legal or other requirement
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Requirements for Cleaning :Legislation
EU Regs 852/2004
• Food Premises are to be kept clean and
maintained in good repair and condition.
• Layout, design and construction
—permit adequate cleaning and disinfection
---protect against accumulation of dirt
• Cleaning agents and disinfectants are not to be
stored in areas where food is handled
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Dubai Municipality Admin Order 20
• Chapter 5 Requirements relating to Design
Facilities and Operation
• Chapter 7 Requirements relating to Control of
Food Storage and Cross Contamination
• Chapter 9 Guidelines for Cleaning and
Disinfection
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BRC Global Standard for Food Safety 2008
Section 4:
4.9
Hygiene and Housekeeping
Cleaning procedures in place
Trained Personnel
Cleaning chemicals fit for purpose
Cleaning practices to minimise risk of cross
contamination
Effectiveness of cleaning verified and
recorded
Procedures revalidated
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ISO 22000:
• Guidance and workbook: Sanitation and
cleaning.
• All aspects appropriately cleaned and
disinfected on a regular basis.
• Well organised hygiene cleaning programme
• Defined standard of results.
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Other Reasons Why Cleaning is Important
In Addition to Food Safety and Legality:
• Pleasant and safe work environment (removes dirt and grease)
• Auditor/ customer confidence (promotes favourable image)
• Aids pest control (removes food and pests easier to see)
• Increased shelf life and equipment performance
• Reduction in:
– Food wastage
Surface deterioration
– Customer complaints Wear and tear
– Physical contamination
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What should a surface be
like after cleaning ?
AND
How Clean is Clean ?
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How to Test for Cleanliness:
Characteristics of an Ideal Method
• Detects microorganisms and food residues with
sufficient sensitivity
• Works equally well on wet and dry surfaces
• Repeatable / Reproducible
• Easy to use
• Rapid
• Cheap
• Foolproof / recordable
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Assessing Cleanliness
• No ideal method
• Any testing usually better than none but
limitations recognised
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Microbiology
• No accepted standard / optimum method
• ISO 18593
• Highly variable results
Moore G and Griffith, C.J. (2007) Problems Associated
with Traditional Hygiene Swabbing: The Need for
Standardisation. Journal of Applied Microbiology; 103: 10901103
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ISO 18593 – Surface Sampling Techniques
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Covers swabbing and contact methods
Swabbing  diluent
Clean and disinfect after sampling
Sponges / cloths  100cm2
Lot of variability allowed
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Low temperature swab transport 1-4C < 24hrs
Contact plate 4 hours
Results used for “trend analysis”
Use of Rt sampling pattern
Contact plate not recommended for pathogens
Copyright © Prof Chris Griffith, UWIC 2006
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Microbiology: Considerations
• Is useful as part of an integrated approach
• What do you need to know
– Cleaning or contamination
• General contamination: presence/absence of
pathogens
• Nature / shape of surface
• Direct/ Indirect contact
• Care with wetting solution if swabbing
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Visual Assessement
“In isolation visual assessment is not a good
indicator of surface cleanliness”
Griffith, 2005 Handbook of Hygiene Control in the Food
Industry
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Relative Merits of Component Residues
• Universality - wide range foods
• Quantity in food
• Sensitivity of Test
• Other
– cost
– time taken
– simplicity
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Non Microbial: Food Component Residues Sole or Combination
• ATP
• Protein
• Reducing Sugar
• Other
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What is ATP ?
• ATP=Adenosine Triphosphate
• Residual surface Soil- blood , faeces, cells
etc contain ATP
• ATP on surface converted into LIGHT
• Light measured in a luminometer
• More light =more residual surface soil
• More residual surface soil less effective the
cleaning
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Testing For Allergens : Direct and Indirect
•Direct –protein detection –sensitivity
•Direct specific allergen peanut,hazelnut,almond,sesame,soya,egg,milk
caesin,crustacean,wheat gluten,sulphite
•Elisa/lateral flow
•Indirect -ATP
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What is Clean?
• What is acceptable / Fitness for purpose ?
• What is attainable?
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Setting Standards: Why?
• “Cannot manage what cannot measure”
• Need to know where you are
• Benchmarking
• Scientific approach
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What is Acceptable?
• USA
<5cfu / cm2
• SFSA
Target
Max
• EU / UK
Meat legislation <10cfu / cm2
1cfu / cm2 Enterobacteriaceae
• Australia
1cfu / cm2
3cfu / cm2
Sat <5cfu / cm2 Unsat <10cfu/cm2
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What is Attainable?
• UWIC
<2.5cfu / cm2 or 250/500 RLUs
Copyright © Prof Chris Griffith, UWIC 2005
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End Product and Surface Testing
Both are Important and both tell you something
about your systems BUT
Copyright © Prof Chris Griffith, UWIC 2007
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End Product and Surface Testing
Both are Important and both tell you something
about your systems BUT
End Product Testing tells you something may
HAVE GONE wrong
Surface testing tells you if something may GO
wrong in the future
Griffith, 2008
Copyright © Prof Chris Griffith, UWIC 2007
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EU Criteria Regs 2073/2005
Sampling of the production and processing
environment can be a useful tool to identify and
prevent the presence of pathogenic
microorganisms in food.
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Summary
• Definition of terms
• Presence of Residues or Microorganisms
on surfaces can pose a health risk
• Important to assess and test surface after
cleaning
• Variety of methods –integrated approach
• Benchmark values
• Predictive nature of surface testing
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Summary 2
• Assessing cleanliness important in Management
- validation, monitoring and verification
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Variety of test methods
Integrated Strategy: micro and non-micro
ATP valuable rapid technique
Assessing cleaning can provide an
early/advance warning of food safety problems
Copyright © Prof Chris Griffith, UWIC 2009
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