Study identifies genes that allow Salmonella to survive in dry conditions

Dry foods such as peanut butter, spices, or flours are generally considered safe from bacterial contamination because a lack of water does not provide a good environment for most microorganisms to grow.

However, under these conditions Salmonella, a microorganism that can cause severe intestinal illness, becomes more resistant to thermal treatments and more virulent.

A new study “General Response of Salmonella enterica serovar Typhimurium to desiccation: A new role for the virulence factors sopD and sseD in survival” by Ryan Fink, assistant professor, published Nov. 8 in the scientific journal PLOS One seeks to explain this phenomenon by identifying the genes that allow Salmonella to survive in extreme conditions.

Salmonella is the focus of a new study by Ryan Fink, published Nov. 8 in the journal PLOS One. Photo courtesy of Alice Maserati

Fink published the article together with Alice Maserati, Antonio Lourenco, Matthew L. Julius, also a professor at St. Cloud State, and Francisco Diez-Gonzalez.

The study identified two genes, known to be essential for the ability of this bacterium to cause severe illness, that are responsible for the ability to survive desiccation and prolonged dry conditions.

The study compared survival and structural characteristics of regular Salmonella to Salmonella mutated to not have the genes and found that the mutant version does not survive as well because of major changes in its response to desiccation.

Fink and his fellow researchers found that these results offer important new information for addressing food safety concerns.

Fink is an assistant professor of biology at St. Cloud State where he also conducts research on Salmonella as a foodborne pathogen. He holds a Ph.D. from the University of Milan, Italy, where he worked on a research project focused on the molecular and quantitative genetics of corn.

He has been researching Salmonella for more than a decade having worked on microbiological projects at North Carolina State University, the University of Miami and the University of Minnesota.