The researchers examined the increase in the incidence of histamine fish poisoning and identified the risk factors associated with this. In addition, they developed recommendations for prevention, and reported their findings in the Journal of the American Medical Association.
Cases in North Carolina from July 1998 to February 1999 were evaluated. Subjects included in the study reported two 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.
A total of 22 cases were reported during the study period - 20 cases occurred during 5 outbreaks, and there were 2 single occurrences.
|Violations of temperature recommendations accounted for 64% of cases.
Of the 22 persons affected, 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 3,245 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 64% cases.
Dr Karen Becker, of the Centers for Disease Control and Prevention, Raleigh, North Carolina, said on behalf of the group, "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," she concluded.