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.