“Study Reveals Listeria Bacteria Can Hide Inside Tissue Of Romaine Lettuce.”
29 March 2017
Purdue University carried out an experiment on romaine lettuce in which they found Listeria monocytogenes living within the tissues throughout the entire growth period of the lettuce. The point of entry for L. monocytogenes is primarily through compromised seed coats, plant tissues, and roots. Once the bacteria has infected a vulnerable host, it can be deadly and it can also cross placental barriers in pregnant women who may miscarry. Listeria can be found in several types of vegetables as well as meats (i.e. hotdogs and deli meats). A Listeria outbreak in 2011 affecting cantaloupes was the second most deadly food borne outbreak in our nation’s history. Listeriosis symptoms may not appear for a couple months, indicating the infection can have a prolonged incubation period before the infected person realizes they are affected. Researchers at Purdue are looking into ways of detecting damaged seed coats and seedlings in an attempt to control pre-harvest contamination.
In class we have studied the potential virulent tendencies of microbes and how they can affect their hosts in numerous ways. We have also discussed the essential ingredients needed for survivability of microbes such as an electron donor, a carbon source, etc.
What I found most intriguing about this article is the fact that Listeria monocytogenes can persist within the tissues of Romaine Lettuce from the seed coat all the way to harvest 60 days later. While I was in the Army, I was a 68R, Medical Food Inspection Specialist. When I first got out, I worked for the USDA Food Safety and Inspection Service as a Consumer Safety Inspector. Both positions required me to enforce federal regulations in regards to safe food handling, operational, and labeling techniques in order to ensure the safety of consumer subsistence. Listeria happened to be one of the most prevalent bacterial species we would test for in processing plants. While I was working for the FSIS in New Jersey, we had a plant that was notorious for Listeria contamination. Their plant was contaminated with Listeria enough times that my agency eventually shut them down. There are only so many non-compliances a plant can have before they lose.
In all honesty, I didn’t know that L. monocytogenes could persist within plant tissue. The majority of contamination we noted for our lab samples was due to introduction from an external source.
The article was short, but to the point. Any reader would be able to understand the content of the article and would be able to learn a bit more about Listeria. I find that additional resource links such as foodsafety.gov, fsis.usda.gov, and CDC.gov, would be beneficial for someone who is unaware of what Listeria can do, who it can affect, etc.
How could we eventually incorporate better safe food handling practices for Ready-To-Eat foods that may potentially be contaminated with Listeria monocytogenes?