Cheese cutting at the UConn Creamery. Credit: Jason Sheldon/UConn Photo
Key points:
- Researchers examined the ability of a protective culture—Hafnia alvei B16—in the prevention of infection by Salmonella.
- According to the findings, Hafnia alvei B16 reduced Salmonella’s ability to invade human intestinal cells by nearly 90%.
- The study also found differences in gene expression and how the two serovars responded to the protective culture in milk.
A new study published by University of Connecticut researchers builds upon our understanding of the ability of a protective culture called Hafnia alvei B16 to prevent infection by two Salmonella serovars, a grouping within the Salmonella enterica species. The serovars studied are common culprits in foodborne illness outbreaks and are resistant to multiple antibiotics.
Presently, most of the protective cultures on the market target gram-positive bacteria rather than gram-negative ones. gram-positive protective cultures are most effective against gram-positive pathogens, meaning there is a need for effective protective cultures against gram-negative pathogens, like E.coli and Salmonella.
In the study, published in Food Microbiology, the team found the Hafnia alvei worked differently than other protective cultures. Most cultures produce antimicrobial metabolites that stop the growth of competing bacteria. Meanwhile, when Hafnia alvei’s metabolites were added to a pathogenic culture, it didn’t stop their growth as expected. But, when the entire Hafnia alvei bacterium was in the presence of E. coli or Salmonella, it did. This told the team it was inhibiting the pathogen’s growth through some other mechanism.
D’Amico’s lab found that growth in the presence of Hafnia alvei decreased the expression of virulence genes in Salmonella and reduced the pathogen’s ability to invade human intestinal cells by nearly 90%.
The same study found differences in how the serovars responded to the protective culture in milk, which may impede the culture’s ability on a global level.