A national outbreak of Salmonella serotype Tennessee infections from contaminated peanut butter: a new food vehicle for salmonellosis in the United States.

BACKGROUND: Salmonella serotype Tennessee is a rare cause of the estimated 1 million cases of salmonellosis occurring annually in the United States. In January 2007, we began investigating a nationwide increase in Salmonella Tennessee infections. METHODS: We defined a case as Salmonella Tennessee infection in a patient whose isolate demonstrated 1 of 3 closely related pulsed-field gel electrophoresis patterns and whose illness began during the period 1 August 2006 through 31 July 2007. We conducted a case-control study in 22 states and performed laboratory testing of foods and environmental samples. RESULTS: We identified 715 cases in 48 states; 37% of isolates were from urine specimens. Illness was associated with consuming peanut butter more than once a week (matched odds ratio [mOR], 3.5 [95% confidence interval {95% CI}, 1.4-9.9]), consuming Brand X peanut butter (mOR, 12.1 [95% CI, 3.6-66.3]), and consuming Brand Y peanut butter (mOR, 9.1 [95% CI, 1.0-433]). Brands X and Y were produced in 1 plant, which ceased production and recalled products on 14 February 2007. Laboratories isolated outbreak strains of Salmonella Tennessee from 34 Brands X and Y peanut butter jars and 2 plant environmental samples. CONCLUSIONS: This large, widespread outbreak of salmonellosis is the first linked to peanut butter in the United States; a nationwide recall resulted in outbreak control. Environmental contamination in the peanut butter plant likely caused this outbreak. This outbreak highlights the risk of salmonellosis from heat-processed foods of nonanimal origin previously felt to be low risk for Salmonella contamination.

Outbreak of Salmonella Wandsworth and Typhimurium infections in infants and toddlers traced to a commercial vegetable-coated snack food.

OBJECTIVE: Human outbreaks of Salmonella infection have been attributed to a variety of food vehicles. Processed snack foods are increasingly consumed by children. In May 2007, state and local health departments and the Centers for Disease Control and Prevention investigated human infections from Salmonella Wandsworth, an extremely rare serotype. MATERIALS AND METHODS: Serotyping and pulsed-field gel electrophoresis were used to identify outbreak-associated illnesses. Food history questionnaires and open-ended interviews were used to generate exposure hypotheses. A nationwide case-control study was conducted to epidemiologically implicate a source. Public health laboratories cultured implicated product from patient homes and retail stores. RESULTS: Sixty-nine patients from 23 states were identified; 93% were aged 10 months to 3 years. Eighty-one percent of child patients had bloody diarrhea; 6 were hospitalized. No deaths were reported. The case-control study strongly associated illness with a commercial puffed vegetable-coated ready-to-eat snack food (mOR = 23.3, P = 0.0001), leading to a nationwide recall. Parents of 92% of interviewed case-children reported that children consumed the food during the week before their illness began; 43% reported daily consumption. Salmonella Wandsworth, 3 additional Salmonella serotypes and Chronobacter (formerly Enterobacter) sakazaki were all cultured from this product, leading to the identification of 18 human outbreak-related Salmonella Typhimurium illnesses. CONCLUSIONS: This report documents a nationwide outbreak associated with a commercial processed ready-to-eat snack food. Cases occurred primarily in infants and toddlers, many of whom frequently consumed the food. Measures are needed to ensure that ingredients added to ready-to-eat foods after the final lethal processing step are free of pathogens.