#31 Food Safety

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ASCLS-WI State ConventionApril 8, 2010Stevens Point, WI

Dr. Roy, Radcliff, Director, Marshfield Food SafetyChief Scientific Officer, Marshfield Food Safety, LLC

New Technologies inFood Safety


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The Importance of Food Testing

In 1999 CDC estimated: 76 million new cases of food-related

illness per year (1 out of every 4 people) 325,000 hospitalizations

5000 deaths

Produce Safety Project (2010) Estimated health related expenses from

foodborne illness to be between $102and $151 billion per year.


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The Importance of Food Testing

Government Accountability Office (1999)

Federal government spent $1 billion

State governments spent $300 million

On food safety efforts (probably more today)

No way to estimate dollars spent by foodcompanies (testing, interventions, processimprovements).


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The Ideal Pathogen Test

Clinical Perspective Robust

Works in all types of food matrices Sensitive

Able to detect a single organism

100 % accurate No false positives or negative


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The Ideal Pathogen Test

Laboratory Perspective Robust

Sensitive 100 % accurate

Easy to use


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The Ideal Pathogen Test Producers perspective

Robust

Sensitive 100 % accurate

Easy to use

Fast Product has a shelf life

Cheap

Adds to cost of production


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Components of a Pathogen Test

The Sample

Setup Enrichment

Analysis


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The Sample

Should represent the lot

Random

Representative

Frequency

Size


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Setup

Should not injure target pathogen

Pre-warmed media

Should maintain sample integrity.

Temperature abuse

Cross contamination


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Enrichment

Should be optimal for target pathogen

media

temperature

time


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Analysis

Detection of the target pathogen

Accurate

Specific

Sensitive

Robust


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Areas to apply new technologies

Sample Setup Enrichment Analysis


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The Sample

Sampling Statistics

Not really a technology

Sampling Devices

Various sponges and spongesicles

Pneumatic samplers

Combo Trim Sampler


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The SampleCombo Trim Sampler Must sample surface tissue Must represent the lot

Must collect a large enough sample

N60 Sampling Collect 60 surface cores 1 diameter and thick Produces approximately 325 to 425 g sample

New device Basically a coring tool that acts like a cheese grater Able to sample entire depth of combo


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Setup Geared toward labor saving

Automated systems

TEMPO from Biomerieux Gemini from BioControl


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Enrichment

Proprietary medias

Optimizing growth rates

Special additives to enhance growth

Selective for specific pathogens

Take advantage of unique biochemical

reaction Differentiation during confirmations


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Analysis

Immuno-magnetic Concentration

Flowcytometry

Phage assays

Membrane conductance

Laser spectrometry


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Immuno-magnetic concentration

Magnetic beads

Coated with antibodies

Used to capture and concentrate

Pathatrix

Dynal

BioControl GDS


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Pros

Allows testing of large volume

Concentrates target organism

Decreased enrichment time


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Cons

Added expense

Added complexity


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Flow cytometry

Some chemistry to tag the cells

Surface antigen

Cytoplasmic protein

DNA or RNA sequence

Passes single cells through a laser

Counts the cells with the correct tag


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Flow cytometry

Pros.

Theoretical ability to detect a single cell

Can be very specific

Able to distinguish dead from live cells


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Flow cytometryConsSample has to very clean

Debris can cause huge interferenceHow do you get a single pathogen cellout of sampleEnrichment negates quantitativepotential


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Phage assays Use live phages for detection

Typically has a period to propagate

target pathogen Phages are added and allowed to

propagate

Detection of the phage


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Phage assays

Pros

Phages are very specific to their host

Phages propagate faster than bacteria

Phages only propagate in live cells


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Phage assay

Cons

Potential contamination of primary

enrichment and the lab. Recombinant tail fibers

Used only to identify target cells


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Thin membrane coated with antibodies

Cells are captured by the antibodies

As cells are captured conductancechanges


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Pros

Good sensitivity

Can test large volume

Can be inexpensive


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Cons

Only as specific as the capture

Interfering compounds

Closely related organisms


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Laser spectrometry

Cells are hit with a laser

Different proteins on the cell surfacescatter the laser

Cells can be identified based on thelaser scatter pattern


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Laser spectrometry

Pros

Based on surface antigens

Can differentiate serotypes/subspecies

Comparable to PFGE

Rapid

Inexpensive


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Laser spectrometry

Cons

Specific preparation

Mainly a typing tool not detection


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Summary

Technological advances have beenmade in all aspects of food testing

One thing that has made the mostimpact?

The Computer!!


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Summary

New technologies are typically moreexpensive

Takes a long time to demonstraterobustness

Food testing industry is slow to adopt

new technologies

#31 Food Safety

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