A Purdue University study shows that the bacteria Listeria monocytogenes can live inside the tissue of romaine lettuce, suggesting that conventional post-harvest sanitization practices might not be sufficient to kill the potentially lethal pathogen.
Research led by Amanda Deering, clinical assistant professor in the Department of Food Science, showed that the bacteria could live within lettuce in every stage of the plant growth process, residing inside the plant tissue. L. monocytogenes can gain entry into the plant through cracked seed coats, small tears in root tissue during germination and damaged plant tissue. The researchers found that exposing lettuce to the bacteria could lead to infection of plant tissue in as little as 30 minutes.
“Knowing this can happen, we need to keep it on our radar as we continue to follow good agricultural practices,” Deering said.
When ingested, the bacteria can be deadly to those with vulnerable immune systems, including pregnant women, the elderly, infants, or those with HIV. L. monocytogenes can also cross the placental barrier in pregnant women, which can trigger a miscarriage.
“For immune-compromised consumers, it’s important to remember, that canned or cooked produce is better,” Deering said.
Read more at Purdue News
The paper is available here.