Tomatoes could help fight off bacterial infections in your gut, a new study has found.

One of the world's most widely consumed vegetables (or perhaps fruit?), they are packed with antioxidants, vitamins, and other compounds – two of which scientists at Cornell University in the US have identified for their potent bacteria-killing properties in a series of cell experiments.

The research team, led by Cornell microbiologist Jeongmin Song, was interested in Salmonella, a genus of enteric bacteria that invade the intestine, often causing food poisoning.

Specifically, the team focused on one typhoidal serotype of Salmonella, Salmonella enterica Typhi, which lives only in humans and causes typhoid fever when it slips into the bloodstream from the gut and spreads through the body.

Like other foodborne pathogens, proper food handling and storage along with access to antibiotics can help people avoid food poisoning from Salmonella.

However, typhoid fever remains a big public health problem in many parts of the world where people don't have access to clean water, sanitation, or typhoid vaccines. It spreads person-to-person via contaminated food and water, and children are at highest risk.

In 2016, the world's first outbreak of extensively drug-resistant typhoid swept across Pakistan, and eight years later, infectious disease experts still fear it could seed regional or global outbreaks if not controlled.

Malnutrition is also common in Pakistan, and other countries throughout Asia, Africa, Latin America and the Caribbean. A 2023 study of 64 countries found that almost half of children under 2 years didn't consume any fruits or vegetables in their diet.

"Our main goal in this study was to find out if tomato and tomato juice can kill enteric pathogens, including Salmonella Typhi, and if so, what qualities they have that make them work," explains Song.

Lab-grown cultures of Salmonella Typhi exposed to freshly pulped tomato juice were killed off within 24 hours, and not because of the juice's acidity.

The researchers scanned the genome of tomatoes (Solanum lycopersicum) looking for genes encoding small proteins called peptides that might act as antimicrobial agents.

From four initial candidates, the team identified two antimicrobial peptides that inhibited the growth of Salmonella Typhi and even killed off a strain resistant to ciprofloxacin, the primary antibiotic used to treat typhoid fever.

Lastly, the researchers modeled the shape of their two lead candidate peptides and simulated their interactions with the bacterial cell membranes. As the modeling predicted, the two peptides ruptured Salmonella Typhi's cell membranes in just 45 minutes.

In further experiments, the compounds also killed Salmonella Typhimurium, a strain of non-typhoidal Salmonella that causes non-lethal food poisoning.

Bearing in mind these are just cell experiments, the study findings aren't a reason to go guzzling tomato juice by the gallon; no one type of food is going to work its magic alone.

Rather, the study underscores public health messaging that encourages people to eat tomatoes as part of a balanced diet that includes lots of other fruits and vegetables – provided they are prepared with good food hygiene methods, it might help ward off illness and food poisoning.

But that depends on affordability and access.

The study has been published in Microbiology Spectrum.