1. Dissecting the Science
Behind Salmonella,
Listeria and E. coli
Claims
An Examination of How the
Science Links to Causation and
Opens the Door to Liability
William D. Marler, Esq.

2. To Put Things in Perspective
• According to the CDC,
pathogens in food cause an
estimated 48 million cases
of human illness annually in
the United States
• 125,000 hospitalized
• Cause up to 3,000 deaths
• Illnesses from food
poisoning pose a $75 to
$125 billion economic
burden in the United States
annually

3. Estimates Differ From Actual Counts
• Annual E. coli O157:H7
Estimates:
– 62,000 illnesses
– 1,800 hospitalizations
– 52 deaths

4. Bottom Line: Most Victims Never Linked
E. coli O157:H7
Patterns Submitted 5,376
Clusters Identified 67
Multi-state Clusters 36
Epi Investigation 19
Vehicle Implicated 4
Regulatory Activity 4

5. The Long Pathway of a Foodborne
Illness Investigation

6. The Pathway Continued
If there are more ill persons
than expected, an
OUTBREAK might be
underway

7. Pathway of a Foodborne Illness
Investigation

8. Proving a Case Using Lab Tests
• All states require reporting of
tests for a number of
pathogens, including;
– E. coli O157:H7
– Salmonella
– Shigella
– Listeria
– Hepatitis A
– Campylobacter
• The process of obtaining the
DNA fingerprint is called
Pulse Field Gel
Electrophoresis (PFGE).

9. Proving a Case with PulseNet
• PulsetNet is an early-
warning system for
outbreaks of foodborne
disease.
• Using this system
scientists at labs
throughout the country
can rapidly compare the
PFGE patterns of
bacteria from ill persons
to help determine where
the outbreak occurred.

10. Proving a Case Using PFGE
• The PFGE pattern of
bacteria isolated from
contaminated food can
be compared and
matched to the PFGE
pattern of the strain
isolated from the stool
of infected persons.
• When paired, PFGE and
epidemiological evidence
are extremely potent in
supporting causation.

11. Causation - Science
• “Causation is an
essential concept in
epidemiology, yet there
is no single, clearly
articulated definition ….”
J Epidemiol Community
Health
2001Dec;55(12):905-
12; Parascandola M,
Weed DL.
• Confidence Interval (CI)
– Range within which
95% of times the true
value of the estimated
association lies (95%
CI)

12. Causation – The Law
• “A proximate cause of an
injury is a cause which, in
natural and continuous
sequence, produces the injury,
and without which the injury
would not have [likely]
occurred. The concept of
proximate causation has given
courts and commentators
consummate difficulty and has
in truth defied precise
definition.” Prosser, Torts, pp.
311-313
• However, “It really is what is
more likely than not. It is 50%
and an extra grain of sand.”
Marler on the law

13. Resources
• Food Safety News
• Foodborne Illness
Outbreak Database
• Marler Blog
• Occupy Food Safety

14. Questions?