Abstract. We show that if the restriction of the Lascar equivalence relation to a KP-strong type is non-trivial, then it is non-smooth (when viewed as a Borel equivalence relation on an appropriate space of types).
An outbreak of Salmonella enterica serotype Agona infections associated with nationwide distribution of cereal from Company X was identified in April 2008. This outbreak was detected using PulseNet, the national molecular subtyping network for foodborne disease surveillance, which coincided with Company X's voluntary recall of unsweetened puffed rice and wheat cereals after routine product sampling yielded Salmonella Agona. A case patient was defined as being infected with the outbreak strain of Salmonella Agona, with illness onset from 1 January through 1 July 2008. Case patients were interviewed using a standard questionnaire, and the proportion of ill persons who reported eating Company X puffed rice cereal was compared with Company X's market share data using binomial testing. The Minnesota Department of Agriculture inspected the cereal production facility and collected both product and environmental swab samples. Routine surveillance identified 33 case patients in 17 states. Of 32 patients interviewed, 24 (83%) reported eating Company X puffed rice cereal. Company X puffed rice cereal represented 0.063% of the total ready-to-eat dry cereal market share in the United States at the time of the investigation. Binomial testing suggested that the proportion of exposed case patients would not likely occur by chance (P < 0.0001). Of 17 cereal samples collected from case patient homes for laboratory testing, 2 (12%) yielded Salmonella Agona indistinguishable from the outbreak strain. Twelve environmental swabs and nine product samples from the cereal plant yielded the outbreak strain of Salmonella Agona. Company X cereal was implicated in a similar outbreak of Salmonella Agona infection in 1998 with the same outbreak strain linked to the same production facility. We hypothesize that a recent construction project at this facility created an open wall near the cereal production area allowing reintroduction of Salmonella Agona into the product, highlighting the resilience of Salmonella in dry food production environments.
Contaminated peanut butter and peanut products caused a nationwide salmonellosis outbreak. Ingredient-driven outbreaks are challenging to detect and may lead to widespread contamination of numerous food products.
We show that there is a Borel graph on a standard Borel space of Borel chromatic number three that admits a Borel homomorphism to every analytic graph on a standard Borel space of Borel chromatic number at least three. Moreover, we characterize the Borel graphs on standard Borel spaces of vertex-degree at most two with this property and show that the analogous result for digraphs fails.
In August 2010, the Minnesota Department of Agriculture and Minnesota Department of Health investigated an outbreak of six cases of Salmonella Newport infection occurring in northwestern Minnesota, which identified fresh blueberries as the cause. Initially, traditional traceback methods involving the review of invoices and bills of lading were used to attempt to identify the source of the outbreak. When these methods failed, novel traceback methods were used. Specifically, supplier-specific 12-digit Global Trade Item Numbers (GTINs) and shopper-card information were used to identify a single blueberry grower linked to cases, corroborating the results of a case-control study in which consuming fresh blueberries was statistically associated with illness (5 of 5 cases versus 8 of 19 controls, matched odds ratio [MOR] undefined, P = 0.02). Consuming fresh blueberries from retailer A was also statistically associated with illness (3 of 3 cases versus 3 of 18 controls, MOR undefined, P = 0.03). Based on initially incomplete evidence in this investigation, the invoices pointed to wholesaler A and grower A, based on first-in-first-out product rotation. However, when point-of-sale data were analyzed and linked to shopper-card information, a common GTIN was identified. This information led to an on-site record evaluation at retailer A, and the discovery of additional records at this location documented the supply chain from grower B to wholesaler C to retailer A, shifting the focus of the investigation from grower A to grower B. This investigation demonstrates the emerging concepts of Critical Tracking Events (CTEs) and Key Data Elements (KDE) related to food product tracing. The use of these shopper-cased data and the event data that were queried by investigators demonstrates the potential utility of consciously designed CTEs and KDEs at critical points in the supply chain to better facilitate product tracing.
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