The Listeria monocytogenes outbreak linked to commercially prepared caramel apples (and some plain apples) last fall was a scary time. People don’t usually think of something as innocuous as a caramel apple as being a vehicle for pathogenic bacteria. But fruits and vegetables are often contaminated. In this particular outbreak, at least 35 people in 12 states were sickened, and the illness contributed to at least three of the seven reported deaths.
The outbreak was difficult to solve, since the product was made from several ingredients, including wooden sticks and sprinkles. The Listeria Whole Genome Sequencing (WGS) Project was a big help for government officials in solving the outbreak.
Government scientists used samples from patients, foods, and the environment at Bidart Brothers packing facilities and other food facilities to trace the outbreak. Patient interviews and traceback were the other two tools in the government’s toolkit.
In November 2014, scientists at the CDC discovered that some Listeria infections in the country were genetically related, suggesting an outbreak. WGS was then used to compare the samples and list them in PulseNet, a national network of public health labs to find others. WGS gives scientists a more detailed look at bacteria strains than pulsed field-gel electrophoresis, which determines the bacteria’s DNA fingerprint.
Public health officials then sent a questionnaire to patients to see what they ate before becoming ill. No food appeared as the culprit at first, but then an official in Texas discovered that two people with listeriosis had eaten caramel apples. When other patients were questioned, most said they had eaten caramel apples. The public was informed about the outbreak.
Traceback was then used to find the suppliers of the apples and other ingredients used to make the product. All of the manufacturers used apples from Bidart Brothers in California. The Bidart Brothers facility was inspected. Environmental swabs found the same Listeria strains that made people sick at the Bidart facility. And the outbreak was solved.
PritzkerOlsen filed a lawsuit in behalf of a Minnesota man who was sickened in this outbreak and are representing a woman in New Mexico who was also sickened as well as a family of a man who died in this outbreak. This outbreak represents how quickly contaminated food can make people sick and how the government can work to solve outbreaks and prevent more illnesses.
