title: A Mexican restaurant-associated outbreak of Salmonella Enteritidis type 34 infections traced to a contaminated egg farm.
abstract: In May 1996, the Georgia Division of Public Health was notified about a cluster of persons with Salmonella Enteritidis (SE) infections in Waycross, Georgia. A matched pair case-control study to determine risk factors for illness found a statistically significant association of SE infection with a history of having eaten at Restaurant A during the 5 days before onset of illness (relative risk = 13 [95% confidence interval (CI) = 3-62, P < 0.01]). In a second case-control study, to determine specific food exposures, consumption of a deep-fried Mexican dish (chile relleno) (4 of 21 cases vs. 0 of 26 controls, odds ratio undefined, 95% CI > 1.46, P = 0.034) was found to be significantly associated with SE infection. An environmental investigation found evidence of suboptimal food storage and cooking temperatures at Restaurant A; cross contamination of foods may have contributed to the low attributable risk identified for chile rellenos. Five of 37 Restaurant A food and environment specimens yielded SE strains. All five positive specimens were from chiles rellenos. Of the seven outbreak-associated strains (six patient isolates and one food isolate from Restaurant A) for which phage typing was conducted, all were phage type 34. A FDA traceback investigation through Restaurant A's single-egg supplier identified the potential source as three interrelated farms in South Carolina. Environmental culture from one of these farms yielded SE phage type 34. As a result of this outbreak, FDA helped institute a statewide egg quality-assurance programme in South Carolina to minimize SE contamination of eggs.
authors.affiliation: Epidemiology and Prevention Branch, Division of Public Health, Georgia Department of Human Resources, Atlanta 30303, USA.
authors.forename: M M
authors.initials: MM
authors.lastname: McNeil
authors.forename: L B
authors.initials: LB
authors.lastname: Sweat
authors.forename: S L
authors.initials: SL
authors.lastname: Carter
authors.forename: C B
authors.initials: CB
authors.lastname: Watson
authors.forename: J T
authors.initials: JT
authors.lastname: Holloway
authors.forename: R
authors.initials: R
authors.lastname: Manning
authors.forename: S F
authors.initials: SF
authors.lastname: Altekruse
authors.forename: P A
authors.initials: PA
authors.lastname: Blake
mesh_terms: D000822:Animal Husbandry; D000818:Animals; D016022:Case-Control Studies; D002645:Chickens; D004196:Disease Outbreaks; D004531:Eggs / Q000382:microbiology*; D005260:Female; D005516:Food Microbiology; D005845:Georgia / Q000453:epidemiology; D006801:Humans; D008297:Male; D011201:Poultry Diseases / Q000382:microbiology; D012147:Restaurants / Q000592:standards; D012480:Salmonella Infections / Q000453:epidemiology* / Q000382:microbiology* / Q000517:prevention & control; D012481:Salmonella Infections, Animal / Q000453:epidemiology / Q000382:microbiology; D012477:Salmonella enteritidis / Q000145:classification / Q000302:isolation & purification*