Sweet buttermilk and Listeria infection in rats
What it found
Sweet buttermilk powder reduced Listeria bacteria settling in the gut and spreading to organs in rats.
It did not protect against Salmonella.
What they found
Animal and lab studies
Less Listeria in rat guts
Rats fed sweet buttermilk had fewer Listeria bacteria in their faeces and in several parts of their gut compared with rats fed skimmed milk. This means less of the pathogen settled in the intestines.
Less spread to organs
Fewer Listeria bacteria reached the spleen and liver in rats eating sweet buttermilk. This suggests the bacteria were less able to move from the gut into other body tissues.
Stronger stomach killing power
Stomach contents from rats fed sweet buttermilk killed more Listeria in lab tests than stomach contents from skimmed milk-fed rats. This extra killing power was not caused by higher acidity or by fatty acids released during digestion.
Blocks bacterial sticking
In lab tests, sweet buttermilk powder stopped Listeria from binding to red blood cells and to human gut cells better than skimmed milk powder did. The authors think this blocking action is the main reason the rats had less infection.
Studies in people and animals
No effect on Salmonella
Sweet buttermilk did not change how much Salmonella appeared in rat faeces. In lab tests using human gut cells, it also did not reduce Salmonella sticking to those cells.
What the authors conclude
- They conclude that sweet buttermilk powder protects rats against Listeria infection, probably by stopping the bacteria from sticking to the gut lining.
- They note that the exact milk fat membrane compound responsible for this protection is still unknown.
- They advise that more research is needed to find out which specific components do the work and exactly how they prevent infection.
How it was done
Food-borne gut infections remain a common problem, and pathogens are becoming harder to treat with antibiotics. The authors wanted to see if components of the milk fat membrane found in sweet buttermilk could fight infection in living animals, since most earlier work was done only in lab tests.
Male rats were fed diets based on either skimmed milk powder or sweet buttermilk powder for 14 days. After that, groups of eight rats per diet were given either Listeria or Salmonella bacteria by mouth. The researchers then measured how much bacteria settled in the gut and spread to organs like the liver and spleen over the following days.
What it can’t tell you
- These experiments were done in rats, so they cannot show what happens in people who eat buttermilk.
- The study tested an infection model rather than everyday food safety, so the results may not apply to normal dietary habits.
- Lab tests showing bacteria failing to stick to cells might not fully reflect how a living human gut behaves.
The paper
- Title
- Sweet buttermilk intake reduces colonisation and translocation of Listeria monocytogenes in rats by inhibiting mucosal pathogen adherence
- Type
- Study
- Evidence
- Studies in people · animals · lab
- Summarised from
- Full text
- Cite
- Sprong RC, Hulstein MF, Lambers TT, van der Meer R (2012). Sweet buttermilk intake reduces colonisation and translocation of Listeria monocytogenes in rats by inhibiting mucosal pathogen adherence. The British journal of nutrition. doi:10.1017/S0007114512000165Free full textPubMed 22370235DOI
Summary written 30 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error