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1
International Commission on
MicrobiologicalSpecifications for Foods (ICMSF)
Useful Testing in Food Safety Management
KATHERINE M.J. SWANSON
Ecolab Eagan, MN, USA
Punta del Este, UruguayMonday
5 October 20092
Discussion Topics
�ICMSF Microorganisms in Foods 8 – overview
�Different tests serve different purposes
�Testing for maximum value
3
Microorganisms in Foods 8: Use of Data for Assessing Process Control and Product Acceptance
�Update previously recommended end-product testing criteria
�Add other useful tests for specific product types
� Include microbial food safety and quality
MICRO-
ORGANISMSIN FOODS
8USE OF DATA FOR
ASSESSING PROCESS CONTROL AND
PRODUCT ACCEPTANCE
ICMSF
4
ICMSF Provides AdviceNo official status
�ICMSF recommendations have no official status
�Official recommendations and standards are the province of:�Governments for national standards and regulations, e.g.
�Intergovernmental agencies for international standards, e.g.
5
Book 8 Contents
�Part 1-Principles� Utility of microbial testing for safety & quality
� Validation of control measures� Verification of process control� Verification of environmental control� Corrective action to re-establish control
� Microbial testing in customer-supplier relationships
�Part 2 – Product Categories� Meats � Poultry� Seafood� Feed & pet food� Vegetables� Fruits� Spices, dried soups, flavorings� Cereals� Nuts, oilseeds, dried legumes� Cocoa and confectionery� Oil based foods� Sugar, syrups, honey� Beverages� Water� Dairy products� Eggs� Shelf stable, heat treated foods� Infants and young children� Formulated foods
Some “work in progress”
examples shared today.
6
Different Tests Serve Different Purposes
2
7
Microbial Testing
� “Microbial testing” means
different things to different people� Reams of data
� Detective game to identify unknown
or causative agent
� Presence/absence or qualitative
reaction that’s observed
� Quantitative measurement of the
microbiological status of a sample or
lot
OR
8
Microbiological Testing Can Assess:
�The safety of food
�Validation and verification procedures in HACCP
�Adherence to GMP/GHP
�The suitability of a food or ingredient for a particular purpose
�The keeping quality (shelf-life) of certain perishable foods
9
When & Where to Test
�When there is good evidence that:
�There is a microbiological problem
o Food safety or quality
o Historical or current
AND
�Testing will help to control the problem
10
The purpose of a test determines:
Lot rejection, process adjustment, recall, outbreak investigation, etc.
The action
Investigational sampling, routine sampling, regulatory sampling, etc.The interpretation
Routine (daily, weekly, monthly, quarterly, etc.) or event triggered
The frequency
Environment, line residue, end product, location collected, size/ number of samples
The sample
Time to results, accuracy, repeatability, etc.The method
Indicator or pathogenThe target
11
Target Organism Examples
Life threatening, chronic sequelae, or long duration OR
Designed for sensitive sub-population
Incapacitating, usually not life threatening
Not life threatening, short duration, self limiting, no sequelae
Measure of GMP
Spoilage, reduced shelf life, no health concern
E. coli O157:H7, C botulinumtoxin or E. sakazakii (infants)
Salmonellae, Yersinia enterocolitica, Shigella flexneri, etc.
S. aureus, B. cereus, C. perfringens, Norovirus, etc.
Coliform, Enterobacteriaceae, etc.
Total counts, yeast, mold, etc.
Severe hazard
Serious hazard
Moderate hazard
Indicator
Utility
ICMSF Hazard Categories
From ICMSF Book 7 12
Key ICMSF Sampling Plan Terms
Level above which is unsatisfactory or requires further investigation
M
Level that separates acceptable quality from marginally acceptable or unacceptable quality
m
Maximum number of sample units with unsatisfactory test results
c
Number of sample units analyzedn
3
13
ICMSF Suggested Sampling Plans for Lot Acceptance Testing
Likely Change Before Consumption
Case 15
n=60, c=0
Case 14
n=30, c=0
Case 13
n=15, c=0
Severe
Case 12
n=20, c=0
Case 11
n=10, c=0
Case 10
n=5, c=0
Serious
Case 9
n=10, c=1
Case 8
n=5, c=1
Case 7
n=5, c=2
Moderate
Case 6
n=5, c=1
Case 5
n=5, c=2
Case 4
n=5, c=3
Indicator
Case 3
n=5, c=1
Case 2
n=5, c=2
Case 1
n=5, c=3
Utility
Increase No ChangeReduceHazard Group
An
aly
tica
l u
nit
= 2
5g
14
Sample Size Influence on Probability of Acceptance
0
0.2
0.4
0.6
0.8
1
1.2
0 5 10 15 20
% Defective
Pro
ba
bil
ity
of
Ac
ce
pta
nc
e
n = 15
n = 30
n = 60
m = 086%
74%
55%
1%
15
Testing to Maximize Value
16
Useful Microbial Testing
�Identification of contamination sources
�Environmental monitoring to identify potential pathogen harborage sites
�Utility and indicator organisms to verify effective controls & trends�Effective processing�Effective control of post process contamination
�Investigation sampling for problem solving
17
Process Example
Process 1
Process 2
Process 3
Packaging Line A
Packaging Line B
Ingredients
18
Result Format Influences Information Provided
Quantative
0
1
2
3
4
5
0 10 20
Lot Number
Lo
g (
CF
U/g
)
Presence/Absence
0 10 20
Lot Number
Positive
Negative
4
19
Trend Analysis Can Inform Process Control
0
1
2
3
4
5
0 10 20
Lot Number
Lo
g (
CF
U/g
)
0
1
2
3
4
5
0 5 10 15 20
Lot Number
Lo
g (
CF
U/g
)
0
1
2
3
4
5
0 10 20
Lot Number
Lo
g (
CF
U/g
)
0
1
2
3
4
5
0 10 20
Lot Number
Lo
g (
CF
U/g
)
20
ICMSF Book 8 Testing Considered
�Primary production
�Ingredients
�In-process
�Processing environment
�Shelf life
�End product
21
Primary production
Included for some product types
�Included when production conditions have a major influence on the microbial quality or safety�Fruits, vegetables, spices, meat, poultry, and fish products
�Examples of samples to consider� Irrigation water, fertilizer, feed, and other on-farm practices
22
Ingredient Testing
�May be useful for some applications and not others, e.g. cocoa powder:�Used in chocolate, no heat treatment?Used in ice cream mix that is subsequently pasteurized
�Questions considered� Is control at the ingredient step necessary for safety or quality?
� Is testing necessary to verify the acceptability of the ingredient?
23
In-Process Testing
�Use to verify a kill step or predict potential re-
contamination
�Examples� Intermediate product, line residues, tailings, wash water� Typically indicators with quantitative results
�Questions considered:� Does the process need to be controlled to prevent increase, ensure decrease, maintain current level, or prevent spread of a microbial concern?
� Is testing needed to verify a) the process is functioning as intended or b) contamination is not occurring in the process?
� Are there locations in the process where accumulated product residue may provide a representative or “worst case” sample that predicts the safety or quality of the final product?
24
Processing Environment Testing
�Use to verify that the environment is under appropriate hygienic control
�Examples� Swabs or sponges for sampling sites on equipment or in the environment
� Rapid testing to verify cleaning & sanitation adequacy
�Benefits –� Identify harborage sites that can contaminate end product� Frequently, earlier detection of issues than end product testing
�Questions considered:� Does the environment need to be controlled to prevent contamination of the product with a microbial concern?
� Will testing be beneficial to verify control of the microbial concern in the environment?
5
25
Shelf Life Testing
�Discussed only if microbial activity is relevant to the commodity
�Purpose – verify adequacy of microbial stability for the product life cycle
�Benefits – may predict issue before they are experience in the market place
�Questions considered: � Is shelf life limited by a microbiological safety or quality concern?� Is shelf-life testing feasible?
26
End Product Testing
�Purpose: � demonstrate successful application of controls or � assess the microbiological status of a lot when no other information exists to assess its status.
�Relative importance of end product testing is lower than that for in-process or environmental testing for many product categories.
�Alternative sampling plans may be appropriate, for example:� Reducing the number of samples for on-going surveillance activity� Increasing the number of samples when investigating significant process deviations or outbreaks.
�Questions considered:� Is end product testing necessary to verify the overall manufacturing process?� Is end product testing relied upon for ensuring the safety or quality of the lot?
27
Preliminary Example: Dried Cereal Products
End product
Not relevantShelf-life
Test for Salmonella and Enterobacteriaceae in the processing
environment
Typical guidance levels:
Enterobacteriaceae – 100-1000 cfu/g
Salmonella – absent
HighProcessing
environment
Test appropriate product residues and in-line samples for
Salmonella.
Typical guidance levels:
Salmonella – absent
HighIn-process
Test for mycotoxins if confidence in raw grains is low
Test nuts, cocoa, and other sensitive ingredients with no
subsequent kill step for Salmonella if confidence in supplier is
low.
HighCritical
ingredients
Useful testing
Relative
importance
28
Preliminary Example: Dried Cereal Products (continued)
NA001011ISO 6579 SalmonellaDried
cereals
Low
MmcnCase
Sampling plan & limits/25gAnalytical
method
MicroorganismProduct
Testing for pathogens is not recommended during normal operation
when GHP and HACCP are effective as confirmed by above tests.
When above testing or process deviations indicate a possible safety
issue, test for Salmonella.
10210252ISO 21528 -
1 / IOCCC
Enterobacter-
iaceae
Dried
cereal
MmcnCase
Sampling plan & limits/gAnalytical
methodMicroorganismProduct
Testing for Enterobacteriaceae is recommended to verify process control.HighEnd
product
Useful testing Relative
importance
29
Microbial Sampling Summary
hTesting safety “into” products usually does not work because of sampling probability
hTesting is recommended to generate meaningful data�Impact quality or safety
hFocus on process control preferred�Environmental monitoring�Selected sampling tailored to the line to verify control
30
The ICMSF recommendations in this presentation are not final.
The work is still under development and subject to internal and external peer review.
30
International Commission on Microbiological
Specifications for Foods (ICMSF)