US Appeals Court Rejects Expert Witness Challenges for Cherry‑Picking Data

Failing to account for the source of each patient's illness in an E. coli O157:H7 outbreak does not mean the expert witnesses ignored evidence or cherry-picked their data, a US district court has found, and a US appellate court has affirmed in not excluding the expert epidemiologists' testimony.

In Cargill Meat Solutions Corp. v. Greater Omaha Packing Co., Inc., 8th U.S. Circuit Court of Appeals, Apr 5 2016, Cargill sued Greater Omaha for damages after about 54 people became ill in 2007 from its frozen American Chef's Selection Angus Beef Patties which were tainted with E. coli O157:H7, a virulent strain of the pathogen that can cause severe illness and even death.

In October 2007, Cargill recalled 845,000 pounds of ground beef linked to the illnesses and paid out over $25 million in settlements with those infected. Cargill claimed that Greater Omaha sold it raw beef trim tainted with the E. coli 0157:H7, which Cargill then used in its recalled ground beef.

To support its claim, Cargill identified as expert witnesses Angie Siemens, PhD, then Cargill's Vice President of Technical Services and its recall coordinator, and two expert epidemiologists, professors of epidemiology Lee Harrison, MD, and Randall Singer, PhD.

Greater Omaha argued that it was not the source of the contamination and moved in limine to exclude all of Cargill's expert witnesses. Greater Omaha asserted that Harrison and Singer had cherry-picked the cases used to link it to the tainted beef, ignoring cases in Ohio with the same E. coli 0157:H7. It argued Siemens should be excluded because she was not an epidemiologist.

The US Department of Agriculture's Food Safety and Inspection Service (FSIS) had initially notified Cargill of the E. coli O157:H7 outbreak. Cargill determined that the contaminated beef was produced at its Butler, Wisconsin plant, and Siemens went there to work with FSIS officials on the recall.

Cargill had used "raw materials" from suppliers in the US and Uruguay in its production of the contaminated Angus Beef Patties, and Siemens had notified the USDA that "… it is not possible to implicate a specific supplier without first observing a pattern of potential contamination."

The Centers for Disease Control and Prevention (CDC) created a list of 54 patients infected with same strain of E. coli O157:H7 as that found in the contaminated beef. The amount of food history for each patient varied, as well as the level of genetic subtyping (DNA fingerprinting) of the bacteria, pulsed-field gel electrophoresis (PFGE) and multiple locus variable-number tandem repeat analysis (MLVA).

Traceback investigations from the patient to the source of the contaminated meat were done by Harrison and Singer for all 54 patients. They opined that the E. coli O157:H7 likely originated from the same source. They traced back infections in Hawaii, Missouri, and New York to Greater Omaha meat that was produced at the same time and late sold to a meat distributor, a grocery store and another meat processing company, in addition to the cases linked to Cargill.

Greater Omaha claimed that Harrison and Singer ignored all the other cases of E. coli O157:H7, noting specifically the Ohio cases. The district court noted that it cited no scientific literature or expert testimony to support its argument that Cargill's experts' methodology was flawed.

Harrison and Singer testified that traceback investigations can be difficult because people often cannot remember what they ate before they became ill, and in the Ohio cases MLVA testing had not been done by the sate, testing which is able to discriminate among E. coli O157:H7 better than PFGE testing, as "… cases that derive from different sources can have indistinguishable PFGE patterns."

The district court rejected Greater Omaha's argument that Harrison and Singer had cherry-picked their data. The appellate court agreed.

Greater Omaha argued as well that Siemens' testimony should have been excluded because she was not an epidemiologist, that she merely restated the opinions of the other experts." The district court found, however, that Siemens had investigated the source of the E. coli O157:H7 at the outbreak and had concluded that Greater Omaha was the source of the contamination. The appellate court agreed.

Although Cargill paid out more than $25 million in settlements, the jury, for unknown reasons, awarded Cargill only $9 million in damages.

Fully cook those frozen beef patties.