During November 1997, the Illinois Department of Public Health was notified by a local physician about a possible case of foodborne botulism. This report summarizes the case investigation, which implicated home-pickled eggs as the cause.
On November 23, 1997, a previously healthy 68-year-old man became nauseated, vomited, and complained of abdominal pain. During the next 2 days, he developed diplopia, dysarthria, and respiratory impairment, necessitating hospitalization and mechanical ventilation. Physical examination confirmed multiple cranial nerve abnormalities, including extraocular motor palsy and diffuse flaccid paralysis. Possible botulism was diagnosed, and a one-vial dose of trivalent (types A, B, and E) antibotulinum toxin was administered. A sample of the patient's serum collected before antitoxin administration demonstrated the presence of type B botulinum toxin. A food history revealed no exposures to home-canned products; however, the patient had eaten pickled eggs that he had prepared 7 days before onset of illness; gastrointestinal symptoms began 12 hours after ingestion. The patient recovered after prolonged supportive care.
The pickled eggs were prepared using a recipe that consisted of hard-boiled eggs, commercially prepared beets and hot peppers, and vinegar. The intact hard-boiled eggs were peeled and punctured with toothpicks then combined with the other ingredients in a glass jar that closed with a metal screw-on lid. The mixture was stored at room temperature and occasionally was exposed to sunlight.
Cultures revealed Clostridium botulinum type B, and type B toxin was detected in samples of the pickled egg mixture at CDC's National Botulism Surveillance and Reference Laboratory. C. botulinum was cultured from the pickling liquid, beets, and egg yolk. The concentration of preformed type B toxin was 1000 times greater in the egg yolks than in the pickling liquid and was undetected in the beets. Peppers from the original commercial container contained no detectable toxin, and bacterial cultures of the peppers did not yield C. botulinum. Beets from the original commercial containers were not available. The pH of the pickling liquid was 3.5 (i.e., adequate to prevent C. botulinum germination and toxin formation. However, the pH of the egg yolk was not determined [normal egg yolk pH: 6.8]).
Reported by: G Rifkin, MD, Rockford Memorial Hospital, Rockford; K Sibounheuang, L Peterson, Winnebago County Health Dept, Rockford; K Kelly, C Langkop, D Kauerauf, E Groeschel, B Adam, C Austin, DVM, S Bornstein, MD, Illinois Dept of Public Health. National Botulism Surveillance and Reference Laboratory, Foodborne and Diarrheal Diseases Br, Div of Bacterial and Mycotic Diseases, National Center for Infectious Diseases; and an EIS Officer, CDC.