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Epidemiologic Notes and Reports Salmonella heidelberg Outbreak at a Convention -- New Mexico

Of approximately 1,000 persons attending a convention October 6-8, 1985, in Santa Fe, New Mexico, 91 reported a diarrheal illness with onset of symptoms between 10 a.m., October 7, and 11 p.m., October 12. Salmonella heidelberg, sensitive to all antibiotics tested, was isolated from the stools of five attendees. Three persons were hospitalized. The ill attendees reported spending over $11,000 on medical costs and lost 117 days of work.

A telephone survey of 76 convention attendees living in New Mexico showed that, of four meals consumed at the convention, only the breakfast of October 7 was significantly associated with illness (p 0.002).

In a subsequent mail survey of the approximately 550 convention attendees who ate the breakfast, the only food significantly associated with illness among the 60% who responded was eggs. All of 91 ill attendees ate the eggs, compared with 189 (92%) of 206 well attendees (p = 0.01). Eggs served at the meal were not available for culture; other eggs from the same distributor were culture-negative for Salmonella. The eggs had been cracked and stored in tall 2-gallon containers in a walk-in refrigerator the evening before the breakfast. They were then cooked in batches in a steamer in the morning. Several attendees commented that the eggs seemed "runny."

Of the staff who worked at the breakfast, three reported illness compatible with salmonellosis with onset during the same period as the conventioneers, and all three had eaten the eggs. S. heidelberg was isolated from the stools of two staff members who did not handle food but had eaten the eggs. Reported by P Weisse, E Libbey, MD, St. Vincent's Hospital, Santa Fe, L Nims, MS, P Gutierrez, MS, New Mexico Scientific Laboratory Div, T Madrid, MPA, N Weber, MS, C Voorhees, V Crocco, C Hules, S Hill, Environmental Improvement Div, TM Ray, R Gurule, F Ortiz, District II Health Office, M Eidson, DVM, CM Sewell, DrPH, S Castle, MPH, P Hayes, Office of Epidemiology, HF Hull, MD, State Epidemiologist, New Mexico Health and Environment Dept; Div of Field Svcs, Epidemiology Program Office, CDC.

Editorial Note

Editorial Note: In the 1960s, eggs were responsible for a large proportion of salmonellosis outbreaks. With improvements in egg processing and quality control, egg-related outbreaks decreased dramatically in the 1970s (1). However, as this outbreak illustrates, egg-related illness remains an important public health concern. Pathogens may proliferate in eggs or in other food refrigerated in large containers, since the center of the container may be inadequately cooled (2). In this outbreak, the fact that many well attendees also ate eggs suggests that only some egg containers were contaminated, that only some eggs were cooked sufficiently to kill the bacteria, or that susceptibility to infection may have varied among the attendees.

For the 10-year period 1973-1982, 11 outbreaks of salmonellosis due to eggs were reported to CDC's Foodborne Disease Surveillance System. Of the 307 ill people in these outbreaks, 45 (15%) were hospitalized, and nine (3%) died (3). S. heidelberg has been frequently associated with poultry, accounting for 29% of Salmonella isolates from poultry submitted to the U.S. Department of Agriculture in 1982 (4).


  1. Cohen ML, Blake PA. Trends in foodborne salmonellosis outbreaks: 1963-1975. J Food Protection 1977;40:798-800.

  2. Bryan FL. Foodborne diseases in the United States associated with meat and poultry. J Food Protection 1980;43:140-50.

  3. CDC. Unpublished data.

  4. CDC. 1982 Salmonella surveillance. Atlanta, Georgia: Centers for Disease Control.

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