Foodborne Illness Outbreaks

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• Foodborne Illness Outbreaks
• and Sprouts

FDA Public Meeting 2005 Sprout Safety May 17,
2005 Amy Dechet, M.D. Foodborne and Diarrheal
Diseases Branch Centers for Disease Control and
Prevention, Atlanta, GA
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Annual Burden of Foodborne Illness in the United
States

• 76 million illnesses
• 325,000 hospitalizations
• 5,000 deaths

Mead et.al., 1999, EID
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What Does This Really Mean?

• 76 million cases annually means
• 1 in 4 Americans ill
• 1 in 1000 Americans hospitalized
• 6.5 billion in medical and other costs

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Foodborne Outbreak Surveillance

• Local and state health departments
• Detect, investigate, and control outbreak
• CDC
• Collect reports of cases, implicated food,
  etiology
• Define an outbreak
• 2 or more cases of a similar illness resulting
  from the ingestion of a common food
• Reporting
• Voluntary and incomplete

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Foodborne Outbreaks Reported to CDC, 1990 - 20031
Enhanced surveillance
1 By states to the Foodborne Disease Outbreak
Surveillance System
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Produce Associated Outbreaks Reported to CDC
1998-2002

• 249 outbreaks
• 6 of outbreaks with reported food source
• 13 of outbreak-associated cases
• Implicated produce
• Generic or multiple 144 outbreaks
• Lettuce 22
• Sprouts 14
• Juice 10
• Melon 9
• Tomato 8
• Berries 6
• Other produce 36

67 of outbreaks with single vehicle
(Preliminary information)
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Produce Item, Outbreaks, Consumption

• Produce outbreaks population eating item
• (1998-2002) (FoodNet Survey
  2002)
• Lettuce 22 73
• Sprouts 14 8 (stealth vehicle)
• Juice 10 26-65
• Melon 9 21-28
• Tomato 8 68
• Berries 6 21-33

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Sprouts Where Does Contamination Occur?

• Multiple opportunities for contamination from
  farm to table
• Field grazing animals
• Mixing same harvest machinery and processing
  facilities
• Scarification bacteria enters seed
• Transport many steps along the way

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Sprouts Bacterial Growth, Detection, and
Elimination

• Sprouting warm, moist environment perfect for
  bacterial growth
• 2-4 log increase in CFU/gram
• Difficult to detect pathogens
• Non-homogenous distribution
• Low-level contamination
• Rarely washed or cooked by consumer

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Sprouts Why They Are Unique

• Multiple pathogens implicated in outbreaks
• Salmonella Typhimurium, Mbandaka, Saintpaul,
  Muenchen, Enteritidis, Kottbus, Chester, Cubana,
  Bovismorbificans
• E. coli O157H7, O157non-motile
• Multiple kinds of sprouts
• alfalfa, mung bean, clover, broccoli, etc.
• International partners

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Sprout Outbreaks by Year
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Alfalfa Sprout Outbreaks by Year(N26)
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Alfalfa Sprout Outbreaks by Year
FDA advises chlorination of seeds
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Alfalfa Sprout Outbreaks and Compliance with FDA
Guidelines by Year
FDA advises chlorination of seeds
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Average Size Outbreak by Year
of Outbreaks of Cases Mean of Cases
1998 4 gt48 16
1999 5 392 78
2000 2 Unknown Unknown
2001 1 32 32
2002 1 5 5
2003 5 53 11
2004 2 38 19
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Produce Item, Outbreaks, Consumption

• Produce outbreaks population eating item
• (1998-2002) (FoodNet Survey
  2002)
• Lettuce 22 73
• Sprouts 14 8 (stealth vehicle)
• Juice 10 26-65
• Melon 9 21-28
• Tomato 8 68
• Berries 6 21-33

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Using Outbreaks to Observe the Effect of
Interventions Juice-Associated Outbreaks,
1994-2004
Juice Labeling reg
Juice HACCP reg
National foodborne outbreak reporting system,
2004 data preliminary
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Conclusions

• Sprout-associated outbreaks represent a small
  proportion of foodborne outbreaks
• Sprouts are one of the most common vehicles
  identified in produce-associated outbreaks
• Current practices are not adequate to prevent
  disease from sprouts
• Outbreak surveillance offers opportunities for
  tracking effectiveness of interventions

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Thank you!
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Alfalfa Sprout Outbreaks and Consumption by Month