copyrights © 2006 silliker, inc. all rights reserved practical considerations in method selection

Copyrights © 2006 Silliker, Inc. All Rights Reserved

Practical Considerations in Method Selection


2

Overview

Background Consideration for the analysis

process Define criteria for method selection Selection Example – Indicator tests Summary


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Producing Safe Food is our First Priority

Consumer Protection & TrustConsumer trust Food Safety is critical to that trust

Business SurvivalOur brands are most important assets

Industry ResponsibilityCommitted to food safety across the

food chain


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Background

Testing is used as a tool to make decisions about the general state of a dynamic system.

Pathogen testing is used as a tool to make decisions about a dynamic system that has greater public health implications.


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U.S. Historical Perspective

Public health systems are representative of our general population shift (rural to urban

Before the 1870’s virtually all food produced and traded locally

Food mass production and transportation abilities changed quality and safety perceptions


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Historical Perspective

Need existed to regulate the safety of food

Regulations focused on dirt Massachusetts Health Act of 1797

Our current public health systems are still based on these principles


Analysis Process


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Business factors to consider

Customer needs Operational Costs Lab complexity and layout


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Analytical Process Steps

Thinking / Planning Sampling Transport Testing Results Decision


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Where do we have method choices Sampling Transport Prep

Microbiological Chemical Physical

Incubation Testing Data Management


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Process Goal

Produce the best result possible System has been optimized and

the parts work together


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Decisions, Decisions, Decisions Conformance Fitness for use Communication


Sampling


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What do we consider

Purpose Quality Safety Investigational

Risk Economics

How many and how much

Desired outcome


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Sampling Considerations

Matrix Analyte Distribution of target in matrix Lot size Storage


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Sampling

What is the matrix Liquid Powder Etc.

How large is the sample What is the container What are the temperature

requirements


Transportation Issues


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Transportation – Key Parameters Identification

Sample can be easily identified Who What When Where How much

Preservation Sample maintained with minimal change in

intrinsic parameters

Protection Sample is protected from external

contaminants


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Sample Attributes

Microbiological levels Lipid Flavor Texture Nutrient composition


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What to consider in transport

Chemical composition of packaging material

Morphology of packaging polymer

Concentration of possible penetrants

Presence of co-permeant


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Environmental Factors

Temperature Relative humidity Packaging characteristics


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Preparation Consideration

Recover or measure a specific analyte

3 factor combination Matrix Analyte Test

Optimize for best outcome


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Incubation

Microbiological or Chemical Temperature Motion – static or shaking Atmosphere - air, microaerophilic, anaerobic

Optimize for best outcome


Testing


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Testing

Key step in process Success is dependent on

previous steps Requires in depth planning Requires stringent quality

systems


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Testing Considerations

Product knowledge Previous use Cost and value Analysis performance


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Testing

Method Selection Analyte Matrix Time Money

Method Execution Receipt Prep Test Result


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Testing - Science Based Criteria Paramount importance to

execute each of these steps well Data used to make key public

health policy decisions Food Safety Objectives – FSO’s Listeria in RTE products Chemical contaminants in foods Allergen levels

Data used to make key corporate decisions


Data Management


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General Data Uses

Safety assessment Pathogen Risk Qualitative and Quantitative data

Quality assessment Spoilage Risk Product Quality Qualitative and Quantitative data

Product and process improvement Criteria development Specification development


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Microbiological Data may be Used to Assess: The safety of food Verification/validation procedures in

HACCP Adherence to GMP/GHP The utility (suitability) of a food or

ingredient for a particular purpose The keeping quality (shelf-life) of

certain perishable foods Acceptability of a food or ingredient

from a source for which there is not confidence in the process


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Data Generation Assumptions

Methods validated For specific matrix

Quality system in place for analysis Analysts Facility Analysis tool

Sampling plans are appropriate


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Application Example – Indicator Testing

Application Example – Indicator Testing


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Definition of an Indicator

Webster’s defines an indicator as

“ an organism or ecological community so strictly associated with particular conditions that its presence is indicative of the existence of these conditions.”


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Definition of an Indicator Test

A test that accurately measures the organisms presence , absence or population count, thereby providing indirect evidence of a particular sample feature or condition


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Common Indicator Tests

TVC Coliforms Enterobacteriaceae Enterococci Lactics Yeast and Mold


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Common Indicator Tests

Psychrophilic counts Anaerobic counts Group Specific Pathogen Screens


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What is the test purpose

Distinguish good from bad Lots Pieces

Determine process changes Determine process approaching

control limits Rate product quality


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What is the test purpose

Determine inspection accuracy Check precision of the measuring

instrument Acquire product design information Measure process capability


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Selection Criteria

Measures what it is supposed to measure

Measurement correlates to a desired outcome

Results are easily interpreted Data is easy to manage


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Selection Criteria

Simple Deployable as close to process as possible Walk away use

Cost Effective Not necessarily “cheapest”

Rapid


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Indicator Acceptance Criteria

The organisms or conditions you measure have a “strong” relationship to a particular outcome or situation


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Test ImplementationTest Implementation


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Situational Assessment

Assess a problem/situation Determine your measurement needs Identify critical parameters Select measurement tool that gives

the best indication of significant change


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Method Assessment

Colony counts Direct detection

microscopy

Cellular component assessment ATP

Physiological properties Impedance/conductance

Metabolites toxins


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Test Assessment

Measurement Protocol Development Testing Validation


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Implementation and Decisions Use the test Collect data Monitor the results Test the system Analyze the data Use for decisions


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Summary

The analytical process is complex Understanding the importance of

each step and their relationships are key

Confidence is built by executing all of the steps well and highlights the need for stringent quality systems and procedures throughout the process


49

Thank You !!Thank You !!


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References

Juran’s Quality Control Handbook, 4th edition; Juran, J.M. ,Gryna, Frank M.

Scientific Criteria To Ensure Safe Food, Institute of Medicine, National Research Council

Milestones in Microbiology ; Brock, Thomas Making Safe Food; Harrigan, W.F. , Park

R.W.A Evaluating The Measurement Process, 2nd

edition; Wheeler, Donald J. , Lyday, Richard W

copyrights © 2006 silliker, inc. all rights reserved practical considerations in method selection

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