Outbreak Investigation

One of Dr. Samadpour’s main research interests when he was at the University of Washington was the early detection of foodborne outbreaks. His analysis of the Jack in the Box outbreak suggested that the outbreak could have been detected in 1992, instead of January of 1993, which would have prevented more than a thousand illnesses. Dr. Samadpour suggested that a national center for genetic fingerprinting of foodborne pathogens was the missing factor needed for early detection of foodborne outbreaks.

JOURNAL OF CLINICAL MICROBIOLOGY, 1995 “We believe that molecular linkage analysis by SLT RFLP or Lambda-RFLP analysis in conjunction with active surveillance and reporting systems could be useful for the detection of clusters of cases of E. coli O157:H7 infection. We propose that the routine usage of these typing methods for E. coli O157:H7 be implemented in a national reference center for the rapid detection of evolving outbreaks. Early detection of outbreaks will avert continued transmission of E. coli O157:H7. Had a national reference center been functioning at the time of this particular outbreak, the infections in November and December 1992 in California, Idaho, Nevada, and Washington could have been linked to the source earlier. This knowledge might have resulted in measures which could have halted subsequent cases of disease.” 

In 1995, Dr. Samadpour invented a new method for genetic fingerprinting of bacteria to facilitate early detection of outbreaks. The method was fast (18 hours time to results – at the time PFGE was a five-day protocol), and economical (less than 5k setup cost). Use of the method resulted in detection of the Odwalla juice outbreak within six days from delivery of the first set of isolates to the lab.

In 1998, at the request of the Georgia State Department of Health, Dr. Samadpour conducted a forensic reexamination of an outbreak of E. coli O157, known as the White Water outbreak in Atlanta, Georgia. Using PFGE, the Center for Disease Control had linked the outbreak to Bauer Meat Company. The closure of the facility and linkage to illnesses of more than 20 children resulted in the owner of the company committing suicide (https://washingtonmonthly.com/2001/01/01/beef-wars/). Dr. Samadpour clearly showed that there was no connection between the outbreak and Bauer Meat Company.

Since then, Dr. Samadpour has been involved in most major outbreaks and recalls in the US. IEH has developed extensive expertise in forensic reexamination of outbreaks and participates in outbreak investigations on behalf of client companies. IEH has the additional advantage of additional knowledge of agricultural production, food manufacturing, distribution, retailing, food service operation, and food trade. Participation of IEH in the investigations results in added confidence and faster decision making by the food companies. Additionally, in instances where epidemiology is not clear or is on the wrong track, IEH is known to bring in scientific evidence to redirect the course of the outbreak investigation. IEH also participates in epidemiological investigations by state health departments by providing free services which include analysis of food and environmental samples, PFGE analysis of outbreak strains (human, food, environmental), whole genome sequencing, and design of environmental and food sampling plans for outbreak investigation.

IEH provides the following services to assist client companies and epidemiologists:

  • Epidemiological investigation

  • Food Recall Center Database

    • Compiles data from 39 sources (28 members of the EU, 6 FDA sources, 2 USDA sources, Australia, Japan and Canada)

    • Enables searching by country, date, source, company name, products effected, and reason for recall

    • Categorized by specific pathogens and allergens

    • If the recall notice is from an online database, a direct link to the full recall is provided

  • Molecular epidemiology capabilities:

    • IEH has one of the largest PFGE databases worldwide and can perform PFGE analysis of hundreds of samples a day.

    • Alternative genetic fingerprinting methods: Ribotyping, Micro Restriction Fingerprinting, RAPD

    • Whole genome sequencing and its application in epidemiology

    • Bioinformatics

  • Application of testing of food and environmental samples in epidemiological investigations. IEH has expedited several outbreak investigations by finding the outbreak strain in foods or in the production environment. This has allowed the client companies to proactively implement public health measures and prevent expansion of outbreaks.

  • Seroepidemiology: IEH has successfully used seroepidemiology to eliminate thousands of cases from class action lawsuits against food companies. These were instances where thousands of claimants with no verified history of infection (medical diagnosis and/or culture confirmed case) had filled claims against companies which were involved in outbreaks.

  • Root cause analysis of outbreaks.

  • Design and implementation of new food safety systems to reduce the chance of another food safety failure.