1. FDA Commissioner’s Fellow
Quantitative Microbial Risk Assessment Approach for Evaluation of Risk Management Options for Sprouts
Hongliu Ding, MD, PhD, MPH
FDA Commissioner’s Fellow

2. Salmonella Outbreak linked to Jimmy John’s Alfalfa Sprouts
From November 1, 2010, through February 9, 2011, 140 infected individuals were reported from 26 states and the District of Columbia.
Tiny Greens Alfalfa Sprouts or Spicy Sprouts at Jimmy John’s restaurant outlets were linked to the outbreak.
From CDC investigation update

3. Taormina et al, Emerg infect dis 1999

4. Guidelines
FDA guidance for industry: reducing microbial food safety hazards for sprouted seeds. 1999
FDA guidance for industry: sampling and microbial testing of spent irrigation water during sprout production
Microbiological safety evaluations and recommendations on sprouted seeds. National Advisory Committee on Microbiological Criteria for Foods. Int J Food Microbiol. 1999;52(3):

6. Montville and Schaffner. J of Food Prot 2004

7. Disinfection Efficacy of 20,000 ppm chlorine
Montville and Schaffner. J of Food Prot 2004
Disinfection Efficacy of 20,000 ppm chlorine

8. Limitations of previous reviews
Only summarized efficacy of chemical disinfection treatment
Limited number of publications
Weight of different studies
Confounding factors (type of sprouts, pathogens et al)

9. Updated review Searched Pubmed to date Identified 52 publications
Extracted data obtained under optimal study conditions
Data analysis adjusted for confounding factors
Evaluated all types of seed disinfection treatments

12. Summary of findings
20,000 ppm chlorine can achieve approximately 3 log cfu/g of pathogen reduction
As the current gold standard, 20,000 ppm chlorine appears not to be the most effective seed disinfection treatment
Physical treatments, especially high pressure, could be promising
None of the seed disinfection treatments guarantees achievement of the target 5 log cfu/g of pathogen reduction
Seed disinfection emphasized, but spent water testing largely ignored!

13. What can we do next?
More studies to test the superiority of physical disinfection treatments
Sampling and testing
Other alternative risk management strategies
Quantitative microbial risk assessment (QMRA)

14. QMRA in food safety Salmonella Enteritidis in Eggs, USDA (1998) FDA
Draft Risk Assessment on the Human Health Impact of Fluoroquinolone Resistant Campylobacter Associated with the Consumption of Chicken (2000)
Draft Assessment of the Relative Risk to Public Health from Foodborne Listeria monocytogenes Among Selected Categories of Ready-to-Eat Foods (2001)
Draft Risk Assessment on the Public Health Impact of Vibrio parahaemolyticus in Raw Molluscan Shellfish (2001)
Listeria in RTE Foods Risk Assessment (2003)
Vibrio in Raw Oysters Risk Assessment (2005)
Highly Pathogenic Avian Influenza in Poultry and Eggs (2010)

15. CCP: Critical Control Point
Seeds from farm
(Initial pathogen load)
Contaminated (discard)
Sprout producers
Disinfection treatment (CCP)
Germination (CCP)
Final rinsing (CCP)
Packaging (CCP)
Storage
Consumers
(Pathogen associated illness?)
Sampling and testing
(seeds)
(spent wash water and sprouts)
(spent irrigation water)
(sprouts)
CCP: Critical Control Point

16. How to do? Risk identification at each step of sprout supply chain
Dose-response assessment
Develop quantitative risk assessment models (Monte Carlo Simulation)
Quantify risk reduction that can be achieved from a microbial sampling and testing program
Quantify the overall risk reduction that can be achieved through a combination of mitigation steps including the microbial sampling and testing plan applied at various sprout supply chain steps

17. Challenge
Establish a feasible and scientifically sound sampling and testing program
When to do? (at least at each CCP)
What to do? (seed, sprouts, spent water)
How to do? (risk analysis algorithm)
Where to start? (QMRA of spent water testing)

18. Hypothetical result of prioritized risk management analysis in sprouts

19. Ask for data Testing data at farm Testing data at packaging
Testing data at storage
Other available data (disinfection et al)

20. Acknowledgements FDA Commissioner’s Fellowship Program IFSH
Dr. Tong-Jen Fu
Dr. Mary Lou Tortorello

21. Questions?
Thank You!