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Dr Bob Whitaker, PMA: You are probably thinking that is an odd title unless you have been monitoring the Blue Bell ice cream recall in recent weeks. Blue Bell hit the news back in mid-March when they recalled ice cream products from one of their production lines owing to contamination with Listeria monocytogenes (Lm). Flashing forward to the end of April, Blue Bell has recalled all of its products currently in the market made at all of its facilities due to potential contamination with Lm. It turns out that arriving at where this case is today has been the result of a long and complex, multi-state outbreak investigation that may reach back as far as 2010. There are currently 10 people sickened by this incident across four states (Arizona, Kansas, Oklahoma, and Texas) with three deaths (all in Kansas). All of the victims were elderly and had other underlying health issues and were hospitalized before developing listeriosis.

While this is a tragedy that we can all relate to, you may still be asking, what does this have to do with produce? A few more pertinent facts might help: When public health officials assess the risk a specific food might present if contaminated with Lm, they look at whether that food would support the growth of Lm (if it were present), the contamination level or “dose,” how the food might be used (cooked, eaten fresh, etc.), and the demographic of the people likely to consume the food. Ice cream would not be considered a food that would support the growth of Lm since it is frozen. So, I guess it might be logical to jump to the conclusion that the dose level must have been very high to make these folks ill and to cause death. From everything I have heard, the dose level in the ice cream is very low, well short of the 100 CFU/g Codex tolerance that we have all come to know. Further, this case represents a unique research opportunity for the U.S. Food and Drug Administration (FDA) as they have an abundance of samples to test; it is a palletized, frozen product that they can work through and analyze to determine the dose levels and characterize the Lm strains that are present. Since the victims were all in the hospital to begin with, FDA can also determine how much of this ice cream was consumed and determine each patient’s exposure to the pathogen.

Read the full article at the PMA website