By Andi Anderson
Listeria monocytogenes is one of the most dangerous bacterial foodborne pathogens in the United States, and pregnant individuals face a much higher risk than the general population.
Each year, around 1,250 people develop listeriosis, and the illness leads to high hospitalization and fatality rates.
Pregnancy‑related cases make up 14% of all infections, and when the bacteria reach the fetus, stillbirth occurs in roughly 25% of those cases. Despite these serious risks, most food safety models have not been designed with pregnant people in mind.
A new study from Michigan State University, led by Dr. Jade Mitchell, addresses this gap. Her team analyzed animal studies involving guinea pigs and gerbils, two species that share important biological traits with humans.
By studying how these animals responded to specific doses of Listeria bacteria during pregnancy, the researchers created two improved models—one predicting maternal infection and one predicting stillbirth.
The study found that fetal brain infection is a more reliable indicator of stillbirth risk than stillbirth data alone. Researchers observed brain infection in every stillborn fetus examined but found none in pregnancies that resulted in healthy births.
This consistent pattern helped them create a more accurate model by combining multiple datasets.
Dr. Mitchell emphasized the importance of these findings, stating, “Public health agencies should use population-specific models like these when developing food safety guidance rather than applying generic population estimates.” She added that precise risk assessment tools will help improve policies as Listeria outbreaks continue to occur.
The authors also stress that pregnancy involves unique biological, behavioral and medical factors. This means pregnant individuals should not be grouped into general categories such as “immunocompromised” when creating food safety guidelines.
The Food and Drug Administration recommends that pregnant people avoid high‑risk foods such as unpasteurized cheeses, raw sprouts, deli meats and smoked seafood unless thoroughly heated. Listeria is unusual because it can grow in refrigerated conditions, making proper food handling especially important.
The study’s co‑authors include recent MSU graduates Carly Gomez and Tyler Stump, who contributed to this important advancement in public health research.
Photo Credit: livingimages
Categories: Michigan, Rural Lifestyle