Context: Histamine poisoning occurs when persons ingest fish in which bacteria have converted histidine to histamine, a process that usually can be controlled by storage at low temperatures. From 1994 to 1997, North Carolina averaged 2 cases annually; however, from July 1998 to February 1999, a total of 22 cases of histamine fish poisoning were reported.
Objectives: To examine the increase in histamine case reports, identify risk factors for poisoning, and develop recommendations for prevention.
Design and setting: Case series evaluated in North Carolina from July 1998 to February 1999.
Subjects: Reported case-patients with 2 of the following symptoms within 2 hours of eating tuna: rash, facial flushing, vomiting, diarrhea, dyspnea, a tight feeling in the throat, headache, or a metallic or peppery taste in the mouth.
Results: Twenty cases occurred during 5 outbreaks, and there were 2 single occurrences. Of the 22 persons affected, 19 (86%) sought emergency medical care. All case-patients ate tuna: 18 ate tuna burgers, 2 ate salad containing tuna, and 2 ate filets. Tuna samples (available from 3 outbreaks) had histamine levels above the Food and Drug Administration regulatory level of 50 ppm (levels were between 213 and 3245 ppm). In 19 cases, the tuna used to prepare burgers or salads was frozen and thawed more than once before serving. Violations of recommended temperature controls were identified in 2 of the 5 restaurants, accounting for 14 (64%) cases.
Conclusions: Tuna burgers, a relatively new menu item in restaurants, were associated with an increase in histamine poisoning cases in North Carolina. Tuna ground for burgers can be susceptible to both temperature fluctuations and bacterial contamination.