In May of 2018, PulseNet, the national molecular subtyping network for enteric pathogens, detected a multistate cluster of illnesses caused by an uncommon molecular subtype of Salmonella serovar Mbandaka. A case was defined as an illness in a person infected with the outbreak strain of Salmonella Mbandaka with illness onset on or after 3 March 2018 and before 1 September 2018. One-hundred thirty-six cases from 36 states were identified; 35 hospitalisations and no deaths were reported. Ill people ranged in age from <1 year to 95 years (median: 57 years). When standardised questionnaires did not generate a strong hypothesis, opened-ended interviews were performed. Sixty-three of 84 (75%) ultimately reported consuming or possibly consuming a specific sweetened puffed wheat cereal in the week before illness onset. Environmental sampling performed at the cereal manufacturing facility yielded the outbreak strain. The outbreak strain was also isolated from open cereal samples from ill people's homes and from a sealed retail sample. Due to these findings, the brand owner of the product issued a voluntary recall of the cereal on 14 June 2018. Additional investigation of the manufacturing facility identified persistent environmental contamination with Salmonella Mbandaka that was closely genetically related to other isolates in the outbreak. This investigation highlights the ability of Salmonella to survive in low-moisture environments, and the potential for prolonged outbreaks linked to products with long shelf lives and large distribution areas.

BACKGROUND: In September 2012, the Centers for Disease Control and Prevention (CDC), U.S. Food and Drug Administration (FDA), and state and local partners investigated an outbreak of Salmonella enterica serovar Bredeney linked to peanut butter (PB). METHODS: A case was defined as infection with the outbreak strain of Salmonella Bredeney between June 1, 2012 and October 31, 2012. Food exposure questionnaires were analyzed by the CDC to determine the food vehicle. The FDA reviewed production information from Retail Chain A's sole supplier of PB, Company A. The PB samples collected from case-patients and Company A were tested for Salmonella. Results. Forty-two case-patients from 20 states were identified. Of 33 case-patients from whom food exposure information was obtained, 25 (76%) shopped at Retail Chain A and 25 (100%) purchased Company A PB. Three state health departments isolated the outbreak strain from opened jars of PB collected from case-patients. The FDA investigators identified multiple deficiencies in current Good Manufacturing Practices (cGMPs) in Company A's manufacturing facility and determined that internal controls were insufficient to prevent shipment of contaminated product. The FDA isolated the outbreak strain of Salmonella Bredeney from implicated product collected at the firm and the environment of the firm's food production facility. CONCLUSIONS: Timely laboratory, investigational, and epidemiologic data led to the voluntary recall of PB by Company A. The FDA suspended Company A's food facility registration, prohibiting the firm from introducing food into interstate commerce. This outbreak underscores the need for effective preventive controls, including robust internal environmental monitoring programs, appropriate action in response to contamination findings, and an improved understanding of food safety at the managerial and corporate levels.

BACKGROUND: Shiga toxin-producing Escherichia coli (STEC) O157:H7 is the causal agent for more than 96,000 cases of diarrheal illness and 3,200 infection-attributable hospitalizations annually in the United States. MATERIALS AND METHODS: We defined a confirmed case as a compatible illness in a person with the outbreak strain during 10/07/2011-11/30/2011. Investigation included hypothesis generation, a case-control study utilizing geographically-matched controls, and a case series investigation. Environmental inspections and tracebacks were conducted. RESULTS: We identified 58 cases in 10 states; 67% were hospitalized and 6.4% developed hemolytic uremic syndrome. Any romaine consumption was significantly associated with illness (matched Odds Ratio (mOR) = 10.0, 95% Confidence Interval (CI) = 2.1-97.0). Grocery Store Chain A salad bar was significantly associated with illness (mOR = 18.9, 95% CI = 4.5-176.8). Two separate traceback investigations for romaine lettuce converged on Farm A. Case series results indicate that cases (64.9%) were more likely than the FoodNet population (47%) to eat romaine lettuce (p-value = 0.013); 61.3% of cases reported consuming romaine lettuce from the Grocery Store Chain A salad bar. CONCLUSIONS: This multistate outbreak of STEC O157:H7 infections was associated with consumption of romaine lettuce. Traceback analysis determined that a single common lot of romaine lettuce harvested from Farm A was used to supply Grocery Store Chain A and a university campus linked to a case with the outbreak strain. An investigation at Farm A did not identify the source of contamination. Improved ability to trace produce from the growing fields to the point of consumption will allow more timely prevention and control measures to be implemented.