Scientists discovered that a specific type of helpful bacteria found in yogurt and healthy animal guts can protect you from Salmonella food poisoning. This bacteria, called Lacticaseibacillus rhamnosus P118, works by creating special compounds that boost your body’s natural defenses and reduce harmful bacteria in your digestive system. The research showed that mice given this bacteria were better protected against dangerous Salmonella infections. This finding could lead to new probiotic foods or supplements that help prevent common foodborne illnesses that cause stomach problems.
The Quick Take
- What they studied: Whether a specific helpful bacteria from yogurt could protect against Salmonella, a common bacteria that causes food poisoning and stomach illness
- Who participated: Scientists tested the bacteria on worms (C. elegans) and mice in laboratory settings. The bacteria strain was originally found in fermented yogurts and healthy pig intestines
- Key finding: Mice that received this special bacteria were significantly better protected against Salmonella infections. The bacteria worked by creating compounds called indole metabolites that strengthened the body’s defenses and reduced harmful bacteria in the gut
- What it means for you: This suggests that eating yogurt or foods containing this specific bacteria might help your body fight off Salmonella food poisoning. However, this is early-stage research done in animals, so more human studies are needed before making dietary changes
The Research Details
Researchers started by screening 290 different bacterial strains from yogurts and healthy animal intestines to find the most promising candidates. They tested these bacteria using two methods: traditional lab tests and a special screening process using tiny worms called C. elegans that can get infected with Salmonella. The bacteria that performed best in these initial tests was then studied in mice to see if it could protect against actual Salmonella infections.
The scientists gave mice the beneficial bacteria before exposing them to Salmonella. They then measured how well the mice survived, how much Salmonella bacteria grew in their bodies, and how their gut bacteria changed. They also analyzed the chemical compounds produced in the mice’s digestive systems to understand how the bacteria was working.
This multi-step approach allowed researchers to identify not just whether the bacteria helped, but also to understand the specific mechanisms and chemical pathways involved in the protection.
This research approach is important because it combines multiple testing methods to build confidence in the results. By first screening many candidates, researchers could focus on the most promising bacteria. Using worms as an initial test is faster and cheaper than using mammals, but testing in mice provides results that are more similar to what might happen in humans. Analyzing the chemical compounds produced helps explain exactly how the bacteria protects against infection, which is crucial for developing effective treatments.
The study was published in eLife, a well-respected scientific journal. The researchers used multiple complementary approaches (bacterial screening, worm testing, mouse studies, and chemical analysis) which strengthens confidence in the findings. However, this is laboratory research in animals, not human studies. The specific bacterial strain tested may work differently in human bodies than in mice. The study doesn’t specify exact sample sizes for all experiments, which makes it harder to assess statistical reliability.
What the Results Show
The bacteria strain P118 showed strong protective effects against Salmonella infection in mice. Mice that received this bacteria before Salmonella exposure had significantly better survival rates and lower levels of Salmonella bacteria in their bodies compared to mice that didn’t receive the bacteria.
The bacteria worked through multiple protective mechanisms. First, it directly killed Salmonella bacteria through antibacterial compounds. Second, it prevented Salmonella from invading the intestinal walls and entering the bloodstream. Third, it reduced the inflammatory response (the body’s overreaction to infection) that normally causes the painful symptoms of food poisoning.
When researchers analyzed the gut bacteria in treated mice, they found that P118 reduced the numbers of harmful bacteria species like Salmonella, Anaeroplasma, and Klebsiella while increasing beneficial bacteria. The treated mice also had higher levels of special compounds called indole metabolites in their stool, which appeared to be the key to the bacteria’s protective effects.
These indole metabolites—including compounds with names like indole-3-acrylic acid and 5-hydroxytryptophan—appear to strengthen the intestinal barrier and enhance the immune system’s ability to fight infection.
The research showed that not only the live bacteria helped, but also the liquid in which the bacteria grew (called supernatant) had protective effects. This suggests that the bacteria produces beneficial compounds that can work independently of the living cells themselves. The study also demonstrated that the bacteria helped restore normal gut bacteria balance after Salmonella infection, which is important because food poisoning often disrupts the healthy bacteria community in your digestive system. Additionally, the bacteria reduced the production of inflammatory molecules that cause the painful symptoms of gastroenteritis.
This research builds on existing knowledge that Lactobacillus species (a family of helpful bacteria) can protect against infections. Previous studies showed these bacteria have antibacterial properties, but this research goes deeper by identifying the specific chemical compounds responsible for protection. The finding that indole metabolites are key protective factors is relatively new and adds to our understanding of how probiotics work. This research aligns with growing evidence that the health benefits of probiotics depend on the specific bacterial strain and the compounds it produces, rather than all Lactobacillus species being equally beneficial.
This research was conducted entirely in laboratory animals (worms and mice), not in humans. Results in animals don’t always translate to humans due to differences in digestive systems and immune responses. The study doesn’t specify how many individual mice or worms were tested in each experiment, making it difficult to assess the statistical strength of the findings. The research doesn’t test whether eating yogurt containing this bacteria would have the same protective effects as direct bacterial administration in the lab. It’s also unclear how long the protection would last or whether repeated exposure to the bacteria is necessary. Finally, the study doesn’t examine potential side effects or whether this bacteria might be harmful to people with weakened immune systems.
The Bottom Line
Based on this research, there is promising but not yet conclusive evidence that this specific bacteria strain could help protect against Salmonella food poisoning. Current confidence level: Low to Moderate (early-stage animal research). At this time, standard food safety practices (proper cooking, handwashing, food storage) remain the most reliable ways to prevent food poisoning. If you’re interested in probiotics, choose yogurts with live cultures, but don’t rely on them as your primary food safety strategy. People with severe food poisoning or weakened immune systems should consult healthcare providers rather than self-treating with probiotics.
This research is most relevant to people interested in probiotics, food safety, and digestive health. It may be particularly interesting to those who frequently experience foodborne illness or have compromised immune systems. However, until human studies are completed, this remains a scientific finding rather than a practical recommendation. People with severe immunosuppression should avoid new probiotic supplements without medical approval. Pregnant women, young children, and elderly individuals should consult healthcare providers before trying new probiotics.
If this bacteria were available as a supplement or food additive, protective effects would likely need to build up over time as the bacteria colonizes the digestive system. Based on similar probiotic research, noticeable effects might take 1-4 weeks of consistent use. However, this timeline is speculative since human studies haven’t been conducted yet. The protection would likely only work if the bacteria is present in your system before Salmonella exposure, not as a treatment after infection begins.
Want to Apply This Research?
- Track daily probiotic intake (type, amount, brand) and any digestive symptoms (bloating, gas, bowel regularity, stomach discomfort) using a simple daily log. Rate digestive comfort on a 1-10 scale each day to monitor changes over 4-week periods.
- If using a probiotic app, set a daily reminder to consume a probiotic food or supplement at the same time each day. Log which probiotic product you’re using and note any changes in digestive symptoms or food poisoning incidents. Create a food safety checklist to track proper food handling practices alongside probiotic use.
- Maintain a 12-week log comparing probiotic use with digestive health metrics and any foodborne illness episodes. Track consistency of probiotic consumption (days per week) and correlate with digestive symptoms. Note any changes in stool consistency, frequency, or discomfort. Share this data with a healthcare provider to assess whether probiotics are providing personal benefit.
This research describes laboratory findings in animals and has not been tested in humans. These results do not constitute medical advice or recommendations for treating or preventing food poisoning. Standard food safety practices (proper cooking temperatures, handwashing, and food storage) remain the most effective ways to prevent Salmonella infection. If you experience symptoms of food poisoning (severe diarrhea, high fever, or bloody stools), seek immediate medical attention rather than relying on probiotics. Before starting any new probiotic supplement, especially if you have a weakened immune system, are pregnant, or take medications, consult with your healthcare provider. This article is for educational purposes only and should not replace professional medical advice.