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Foodborne Salmonellosis in a Workers' Compound, Saudi Arabia.


In Saudi Arabia and other Gulf states, foreign workers are often provided both housing and food under their contracts. Detection and prevention of foodborne disease in such concentrations of workers is a major concern. On Oct. 15, 1994, we learned of 19 Filipino employees from the same housing compound with acute febrile gastroenteritis, and we began an investigation to determine the cause of the outbreak.


We searched all 59 cabins for residents who between Oct. 11 and Oct. 16, 1994, developed diarrhea (≥ loose stools/24 hours) and fever (case-persons). For each case-person, we selected one control-person at random from the same cabin and interviewed both about foods eaten from Oct. 10 to Oct. 14. Stool cultures were done for all case-persons and all 16 kitchen employees.


We identified 21 cases among 204 professionals (attack rate [AR] = 10%) and 1 case among 1129 laborers (AR = 0.09%). Salmonella group D was isolated from stool of all 22 cases. None of the kitchen staff was sick or had Salmonella in their stool. Illness was associated with eating dinner after 9 p.m. on Oct. 11 and Oct. 12 (p<0.00001) and with eating chicken adobo for the Oct. 11 dinner (odds ratio [OR] = infinity, 95% confidence interval [CI] 3.9-infinity, p<0.0000 [chi-square with Yates correction]). The median period from eating the chicken to the onset of illness was 38 hours. Chicken (210 kg) had been cooked between 2-4 p.m. on the stovetop in two pots. Food preparation surfaces and utensils were rinsed between handling fresh and cooked chicken. After cooking, the chicken was held at 35-40o C and served between 5 p.m. and 10 p.m.


Salmonella, probably introduced on fresh chicken, may have survived inadequate cooking conditions or were introduced after cooking via contaminated utensils. The association with eating after 9 p.m. indicates that Salmonella present after cooking needed to multiply for about 4 hours to reach an infective dose. Health authorities need to ensure that large-volume kitchens for contract workers prepare and store foods at temperatures where bacteria are killed or cannot multiply.