International outbreak of Salmonella Oranienburg due to German chocolate.
BACKGROUND
This report describes a large international chocolate-associated Salmonella outbreak originating from Germany.


METHODS
We conducted epidemiologic investigations including a case-control study, and food safety investigations. Salmonella (S.) Oranienburg isolates were subtyped by the use of pulsed-field gel electrophoresis (PFGE).


RESULTS
From 1 October 2001 through 24 March 2002, an estimated excess of 439 S. Oranienburg notifications was registered in Germany. Simultaneously, an increase in S. Oranienburg infections was noted in other European countries in the Enter-net surveillance network. In a multistate matched case-control study in Germany, daily consumption of chocolate (matched odds ratio [MOR]: 4.8; 95% confidence interval [CI]: 1.3-26.5), having shopped at a large chain of discount grocery stores (MOR: 4.2; CI: 1.2-23.0), and consumption of chocolate purchased there (MOR: 5.0; CI: 1.1-47.0) were associated with illness. Subsequently, two brands from the same company, one exclusively produced for that chain, tested positive for S. Oranienburg. In two other European countries and in Canada chocolate from company A was ascertained that also contained S. Oranienburg. Isolates from humans and from chocolates had indistinguishable PFGE profiles. No source or point of contamination was identified. Epidemiological identification of chocolate as a vehicle of infections required two months, and was facilitated by proxy measures.


CONCLUSIONS
Despite the use of improved production technologies, the chocolate industry continues to carry a small risk of manufacturing Salmonella-containing products. Particularly in diffuse outbreak-settings, clear associations with surrogates of exposure should suffice to trigger public health action. Networks such as Enter-net have become invaluable for facilitating rapid and appropriate management of international outbreaks.
Werber
Dirk
D
Department of Infectious Disease Epidemiology, Robert Koch-Institut, Berlin, Germany. Dirk.Werber@nphs.wales.nhs.uk
Dreesman
Johannes
J
Feil
Fabian
F
van Treeck
Ulrich
U
Fell
Gerhard
G
Ethelberg
Steen
S
Hauri
Anja M
AM
Roggentin
Peter
P
Prager
Rita
R
Fisher
Ian S T
IS
Behnke
Susanne C
SC
Bartelt
Edda
E
Weise
Ekkehard
E
Ellis
Andrea
A
Siitonen
Anja
A
Andersson
Yvonne
Y
Tschäpe
Helmut
H
Kramer
Michael H
MH
Ammon
Andrea
A
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002099:Cacao / Q000382:microbiology*; D002170:Canada / Q000453:epidemiology; D002182:Candy / Q000382:microbiology*; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D004196:Disease Outbreaks; D016521:Electrophoresis, Gel, Pulsed-Field / Q000379:methods; D005060:Europe / Q000453:epidemiology; D005260:Female; D005516:Food Microbiology; D005858:Germany / Q000453:epidemiology; D006801:Humans; D007223:Infant; D008297:Male; D008875:Middle Aged; D012307:Risk Factors; D012475:Salmonella / Q000235:genetics / Q000302:isolation & purification*; D012478:Salmonella Food Poisoning / Q000453:epidemiology / Q000382:microbiology*