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Epidemiologic Notes and Reports Update: Salmonella enteritidis Infections in the Northeastern United States

New England and the Middle Atlantic region* experienced a fivefold increase in the reported isolation rate of Salmonella enteritidis between 1976 and 1985 (1). Consequently, a regional S. enteritidis Working Group was established in 1986 to coordinate investigations of S. enteritidis outbreaks. Investigations of recent outbreaks and related studies suggest that many S. enteritidis infections in the Northeast are associated with eggs.

Fourteen S. enteritidis outbreaks have been reported to CDC from the Northeast since October 1, 1986. The vehicles of transmission have been identified for 10 of the outbreaks. At least six of these vehicles were either eggs or foods which contained raw or undercooked eggs (homemade eggnog prepared with store-bought eggs, Monte Cristo sandwiches made of sliced cooked meat and cheese on bread dipped in raw egg and grilled, and Caesar salad dressing made with raw eggs). The outbreak-associated eggs were all USDA grade A shell eggs, and, in each instance, the food preparation history suggested the eggs were eaten raw or undercooked. The outbreak-associated eggs were not available for culture. However, in an outbreak associated with riceballs (made with eggs) in September 1986, S. enteritidis was cultured from an egg-breaking machine in the restaurant involved. Reported by: S Schultz, MD, New York City Dept of Health; D Morse, MD, State Epidemiologist, New York Dept of Health. W Parkin, MD, State Epidemiologist, New Jersey Dept of Public Health. GF Grady, MD, State Epidemiologist, Massachusetts Dept of Public Health. EJ Witte, VMD, MPH, State Epidemiologist, Pennsylvania Dept of Health. JL Hadler, MD, MPH, Connecticut Dept of Health Svcs. RL Vogt, MD, State Epidemiologist, Vermont Dept of Health. E Schwartz, MD, State Epidemiologist, New Hampshire Dept of Health and Welfare. KF Gensheimer, MD, State Epidemiologist, Maine Dept of Human Svcs. PR Silverman, PhD, State Epidemiologist, Delaware Dept of Health and Social Svcs. E Israel, MD, State Epidemiologist, Maryland Dept of Health and Mental Hygiene. Div of Field Services, Epidemiology Program Office; Enteric Diseases Br, Div of Bacterial Diseases, Center for Infectious Diseases, CDC.

Editorial Note

Editorial Note: Salmonellosis associated with eggs is not a new problem. Large outbreaks of salmonellosis associated with bulk egg products and cracked shell eggs (2,3) led to the passage of the Egg Products Inspection Act in 1970. This law required pasteurization of all bulk egg products and federally-supervised inspection of shell eggs for "checks" or cracks. Since enactment of this legislation, there have been fewer egg-associated outbreaks of salmonellosis, and CDC has not received any reports of outbreaks associated with bulk egg products (4).

These recent outbreaks suggest that egg-associated S. enteritidis is an emerging public health problem and show the importance of routine serotype-specific surveillance. Eggs can become contaminated with Salmonella in several ways. Fecal soiling may contaminate egg shells, and the internal contents of the egg may occasionally be contaminated by organisms entering through hairline cracks in the shell (5). In addition, if there is an ovarian infection in the hen, an egg yolk may become infected by certain serotypes of Salmonella before the shell is formed (6). It is not known whether S. enteritidis is one such serotype.

As is true for meat, poultry, raw milk, and other raw foods of animal origin, proper handling and cooking of eggs can minimize the risk of salmonellosis. Thorough cooking kills Salmonella. Consumers concerned about the proper handling of egg-containing foods should contact their county extension home economist or call the USDA Meat and Poultry Hotline (800-535-4555). Further research is needed to understand the ecology of Salmonella colonization in poultry and other food-animal species and to determine ways to further reduce the contamination of eggs and other foods derived from animals.

Clinicians are encouraged to report cases of salmonellosis to their state health department. Isolates of Salmonella can be submitted to state laboratories for serotyping to support epidemiologic investigations.


  1. CDC. Increasing rate of Salmonella enteritidis infections in the Northeastern United States. MMWR 1987;36:10-1.

  2. Sanders E, Sweeney FJ Jr, Friedman EA, Boring JR, Randall EL, Polk LD. An outbreak of hospital-associated infections due to Salmonella derby. JAMA 1963;186:984-6.

  3. CDC. Proceedings: national conference on salmonellosis, March 11-13, 1964. Atlanta, Georgia: US Department of Health, Education and Welfare, Public Health Service, 1965; DHEW publication no. (PHS)1262.

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

  5. Board RG. The course of microbial infection of the hen's egg. J Appl Bact 1966;29:319-41.

  6. Snoeyenbos GH. Pullorum disease. In: Hofstad MS, Calnek BW, Helmboldt CF, Reid WM, Yoder HW Jr, eds. Diseases of poultry. 7th ed. Ames, Iowa: Iowa State University Press, 1978:80-100. *Defined by the U.S. Bureau of the Census as New Jersey, New York, and Pennsylvania.

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