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.
References
CDC. Increasing rate of Salmonella enteritidis infections in
the
Northeastern United States. MMWR 1987;36:10-1.
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.
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.
Board RG. The course of microbial infection of the hen's egg.
J
Appl Bact 1966;29:319-41.
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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