“No illnesses have been reported to date.” How many times have we read a food recall notice posted on either the FDA or FSIS websites by the companies recalling the product with that self-serving statement? I would say most of the time.

In the past few months the CDC has reported three outbreaks – one Salmonella outbreak and two Listeria outbreaks that have used Whole Genome Sequencing to connect ill people to tainted product. Perhaps “No illnesses have been reported to date” is a statement of the past trumped by science.

So, what is the science?

State and CDC Public health investigators have used the PulseNet system to identify cases of illness that were part of and outbreak for nearly two decades. PulseNet, the national subtyping network of public health and food regulatory agency laboratories coordinated by CDC, receives from state laboratories DNA “fingerprints” of bacteria obtained through diagnostic testing using Pulsed-field Gel Electrophoresis (PFGE).

Multiple Locus Variable-number Tandem Repeat Analysis (MLVA) is another technique used by scientists to generate a DNA fingerprint for a bacterial isolate. Scientists usually perform MLVA after PFGA to find out more specific details about the type of bacteria that may be causing an outbreak.

Whole Genome Sequencing, is a newer, more highly discriminatory subtyping method, that has been used to define the following outbreaks:

  • Oasis Brands Inc., Cheese Recalls and Investigation of Human Listeriosis Cases – One person became ill in September 2013 and two persons who became ill in June and August 2014. These three ill persons were reported from three states: New York (1), Tennessee (1), and Texas (1). All ill persons were hospitalized. One death was reported in Tennessee. One illness was related to a pregnancy and was diagnosed in a newborn.

“No illnesses have been reported to date,” may well be a statement of the past.