In May 2021, state and local public health agencies in Washington and the Washington State Department of Agriculture (WSDA) investigated an outbreak of Shiga Toxin E. coli (STEC). The outbreak was assigned the CDC outbreak number 2105WAEXH-1.
A confirmed outbreak case was defined as a person infected with E. coli O157:H7 who matched the outbreak strain by whole-genome sequencing (WGS) within 0-3 alleles, or a person infected with E. coli O103 who matched the second outbreak strain by WGS within 0-1 alleles and had a symptom onset or isolation date on or after December 27, 2020. A probable outbreak case was defined as a clinically compatible case, epi-linked to a confirmed case. A suspect outbreak case was defined as any clinically compatible case with STEC of unknown serotype and a stx 2+, stx1- profile, with post-diarrhea hemolytic uremic syndrome (HUS), and a known exposure to Pure Eire Dairy yogurt.
A total of 26 ill cases were identified in this outbreak. This total included 17 laboratory confirmed cases of E. coliO157:H7 reported by six local health jurisdictions in Washington state (n=14) and Arizona (n=3). There were 9 probable cases in Washington state (n=8) and Arizona (n=1). Washington patients resided in Benton, Clark, King, Grant, Snohomish, and Walla Walla counties. Cases in Arizona occurred among family members who hosted relatives from Moses Lake, Washington in the week before symptom onset. Ill children of the visiting Washington family and children of the Arizona family were babysat together.
Illness onset dates ranged from December 27, 2020, to May 27, 2021. Two patients were co-infected with E. coliO157:H7 and E. coli O103:H11. All isolates (both strains) were highly related, within 0-3 alleles by WGS. Case patients ranged in age from 1 to 71 years. Ten confirmed cases and 7 probable cases were nine years old or younger. Eleven people were hospitalized (10 confirmed cases, 1 probable case) and 5 developed HUS (4 confirmed cases, 1 probable case). No one died.
Early in the investigation, epidemiologists determined that foods consumed by many of the case patients were purchased at PCC, a grocery chain located in western Washington. Organic produce items were consumed by several cases, which triggered an extensive traceback investigation. Strawberries, avocados, and leafy greens were traced back to three distributors. However, there was little or no repacking done by the distributing firms, and these items were widely sold at other grocery chains. Investigators theorized that there would be more cases geographically dispersed throughout Washington and elsewhere if produce was the source of the outbreak. Additional customer purchase histories and interviews with patients and their families revealed that PCC Market Brand yogurt was consumed by all the early cases. Investigators refocused their attention to traceback and trace forward of the yogurt.
PCC Market Brand yogurt was produced by Pure Eire Dairy in Othello, Washington. Ninety percent of the product produced was PCC labeled. Ten percent was distributed to other stores, cafes, and CSAs. Thirteen of 14 primary, outbreak-associated cases consumed Pure Eire Dairy products. Ten consumed PCC brand yogurt, two consumed Pure Eire milk, and one consumed Pure Eire labeled yogurt. It was unclear if the fourteenth case consumed Pure Eire yogurt, although the case was cared for by a relative who had purchased Pure Eire yogurt at Yolk’s Fresh Market. The relative was unsure if the case consumed it.
On May 14, Pure Eire Dairy initiated a voluntary recall of its products. The next day, the Washington Department of Health issued a public health alert dissuading public consumption of Pure Eire Dairy yogurt products. Pure Eire Dairy later ceased production of all products. On May 17, 2021, Washington State Department of Agriculture (WSDA) investigators conducted a site visit to Pure Eire on May 17, 2021. They collected 40 environmental samples focusing on the yogurt process. On May 18, investigators returned to the dairy and collected 15 finished, pasteurized milk samples from commerce. WSDA Microbiology did not isolate STEC in any of the yogurt samples or pasteurized milk samples.
On May 25, 2021, WSDA provided Pure Eire Dairy with a written list of observations noted during the on-site investigation. Observations pertained to facility construction, condensation, process separation, equipment storage and design, packaging material storage and exterior facility grounds. Employee practices and adequacy of sanitation could not be assessed as the firm was not in production at the time of the on-site investigation. Specifically, the WSDA noted the following.
- The milk production plant was not maintained in a way to facilitate adequate cleaning and sanitation of the environment by allowing standing water to accumulate. Exposed aggregate and pooled water were observed on the floor in the yogurt machine room and on the floor near the vat pasteurizers.
- The milk production plant was not maintained in a way to minimize peeling paint and rust which limits adequate cleaning and sanitation. Rust and peeling paint were observed on the edges of the ceiling vent in the middle of the pasteurizer room, on the edge of the doors leading to the washroom from the pasteurizer room and the gray electrical box between the two chart recorders had bubbling and peeling paint in the pasteurizer room.
- The milk production plant was not constructed and maintained in a way to minimize condensation. Condensation drip was observed falling from ceiling panels in the walk-in cooler for the whey drain room. Condensation was also observed on the door to the walk-in cooler in the whey draining room, on the ceiling of the walk-in cooler in the mixing room and pasteurizer ceiling.
- There was inadequate separation between the cow milking barn and milk processing plant and storage areas.
- The milking production plant was not maintained in a clean and sanitary condition. Numerous flies were noted throughout the interior of the milk plant and equipment room. The third yogurt hanging rack drain pan stored on the west side of the whey-draining walk-in cooler had green mold-like substance. Yellow and white residue was observed in the drain pans of the yogurt hanging racks stored on the east side of the whey draining walk-in cooler. There was pooled water, yellow-brown residue (apparent manure) and dirt noted on the floor in the equipment room. The equipment room is the common entrance to the milk processing plant and the milking parlor.
- Surplus equipment was stored in the processing area.
- Equipment and utensils were not constructed or maintained in a way that allowed for adequate cleaning.
- Food contact packaging material was not segregated in a way to ensure it was clean, protected from contamination and suitable for processing.
- The boots on the rotating agitator shafts placed above the lid for pasteurization vats 1&2 in the pasteurizing room did not rotate with the shafts so as to provide protection and shielding from a potential source of contamination into each vat.
- During equipment testing, the vat pasteurizer leak detect valve was not operating as designed.
- The exterior ground of the milk production plan was not maintained in a condition that protected against contamination of food. Milk crates were being stored outside directly against the south side of the milk processing plant, providing pest harborage in this area. Pallets of glass bottles were stored outside open to the environment behind the milk processing plant. A mouse was observed running underneath the pallets of open glass containers during the inspection.
In early June, WSDA returned to the dairy several times to collect more samples (well water, glycol, and finished fluid milk), test the vat pasteurizer, and to verify that corrective measures had been implemented. All samples tested negative for STEC.
On June 7, Pure Eire Dairy resumed fluid milk production with primary distribution in Eastern Washington, as well ice-cream mix production. In mid-June, the dairy notified regulators that they wanted to resume yogurt production, although they withdrew that request on June 25.
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If you or a family member became ill with an E. coli infection or HUS after consuming food and you’re interested in pursuing a legal claim, contact the Marler Clark E. coli attorneys for a free case evaluation.