The US Centers for Disease Control and Prevention (CDC) and the Food and Drug Administration (FDA) are investigating an outbreak of Listeria monocytogenes infections associated with certain Blue Bell brand ice cream products.
Five cases have been included in the outbreak investigation to date, all in the state of Kansas and all patients in the same hospital when they became ill between January 2014 and January 2015. Three of the cases have since died. It is suspected that the infection was acquired in the hospital and whole genome sequencing showed that Listeria isolates from four of the cases were closely related.
The investigation has established a link with Blue Bell brand ice cream. Four of the patients affected consumed milkshakes made with Blue Bell “Scoops” ice cream before becoming ill. Samples of Blue Bell ice cream, including the Scoops product, tested by health officials in South Carolina and Texas were found to be contaminated with Listeria monocytogenes. Three strains isolated from the ice cream had genetic fingerprints indistinguishable from strains isolated from patients.
The ice cream manufacturer, Blue Bell Creameries in Texas, has withdrawn 10 products from the market and has closed the production line on which they were made. However, CDC is concerned that people may still have contaminated ice cream in home freezers and is advising the public not to eat it.
More information about the outbreak investigation can be found here.