Seattle – King County Public Health investigated an outbreak of probable scombroid poisoning with nausea, diarrhea, and flushed face associated with All Water Seafood & Oyster Bar in the Loews Hotel 1000 in Seattle.

Since November 4, 2019, 3 people from one meal party reported becoming ill after eating cooked tuna from All Water Seafood & Oyster Bar on November 4, 2019.

Environmental Health investigators visited the restaurant on November 6, 2019. Investigators did not find any food safety concerns at the restaurant related to preparation or refrigeration of tuna. No tuna from the same batch that was served to the ill meal party remained at the time of the investigation. The restaurant voluntarily discarded all prepared tuna.

We reported this outbreak to the U.S. Food and Drug Administration (FDA) to investigate the source of the tuna to make sure appropriate storage and handling of tuna is happening before distribution to restaurants and other food establishments.

There are no laboratory tests to diagnose scombroid in people. Testing can be done on food, however samples of the tuna were not available. Symptoms experienced by the ill people are suggestive of scombroid.

FDA and state health authorities are investigating incidents of scombrotoxin fish poisoning linked to yellowfin tuna, also sometimes called ahi tuna. As a result of this investigation, FDA has placed Truong Phu Xanh Co, LTD of Vietnam on Import Alert, which provides information to FDA field staff that they may detain the firm’s yellowfin tuna without physical examination. Detained product will not enter the United States unless the importer proves that it meets U.S. food safety standards.

FDA asked for the supplier of yellowfin tuna associated with most of the illnesses, Truong Phu Xanh Co., LTD of Vietnam, to initiate a voluntary recall of all of its imported yellowfin tuna with production dates from January 2019 to the present. At this time, the firm has not recalled any product.

As part of the investigation, FDA evaluated the firm’s Hazard Analysis and Critical Control Point (HACCP) Plans. A HACCP Plan details a firm’s management system to address food safety through the analysis and control of biological, chemical, and physical hazards. Since FDA’s evaluation of this plan identified deficiencies, we asked for Truong Phu Xanh Co., LTD of Vietnam to initiate a voluntary recall of all of its imported yellowfin tuna with production dates from January 2019 to the present.

The investigation has identified 47 illnesses of scombrotoxin fish poisoning that occurred between August 8, 2019 and October 15, 2019.

Throughout the investigation, FDA and states have also been collecting product samples for testing. Scombrotoxin fish poisoning occurs when fish begin to spoil, resulting in increased histamine levels. Therefore, product samples cannot be linked to case patient samples through Whole Genome Sequencing (WGS) or Pulsed-Field Gel Electrophoresis (PFGE) analysis like for other foodborne illnesses, e.g., Salmonella or Listeria. Instead, samples are tested for decomposition and/or histamine levels. Multiple samples have been collected and analyzed, with positive results for decomposition or high histamine levels in products imported from Truong Phu Xanh Co., LTD.

FDA and state partners collected epidemiologic and traceback information for reported illnesses. As additional epidemiologic and traceback information was collected, FDA and state partners were able to work with companies throughout the supply chain to voluntarily recall implicated product. While recalls were conducted at various points in the supply chain, there may be additional product still on the market that could cause illness.

Ultimately, the coordinated investigation was able to identify Truong Phu Xanh Co., LTD as the common supplier of tuna that was likely consumed by most of the ill people.

Because scombrotoxin fish poisoning causes temporary or medically reversible adverse health consequences this incident did not meet the threshold for the use of FDA’s mandatory recall authority.

It has been determined that the source of the tuna for the illnesses announced by Seattle-King County Public Health Department is not related to Truong Phu Xanh Co., LTD.