The team, led by scientists from the University of Manchester in the UK, found that the bacteria use a two-step process to pass the body's natural defenses.
In the process of trying to expel the bacteria, the body generates high levels of intestinal acid. While that acid can help kill the bacteria, it also causes the release of calcium, which the bacteria can use to protect themselves.
According to the study published in the journal Nature Microbiology, the bacteria form 'hibernating spores' that can lie dormant in the gut. They then wait until the acid levels drop and the calcium levels increase before reawakening and becoming pathogenic.
"This discovery provides new hope that we can develop an alternative preventative strategy to target this bacteria," said Julian Cox, the lead author of the study. "Developing vaccines presents many problems so this kind of preventative approach could be the key to tackling such infections."
Food-borne infections such as Salmonella and E. coli are a major public health problem, with over 600 million affected worldwide each year.
One in five people will develop a food-borne infection each year, leading to hospitalization in 10-30% of cases and death in 1-5%.
Food poisoning is particularly dangerous for infants and young children, with infants under 1 year old 20-150 times more likely to die from a food-borne infection than older children and adults.
Symptoms often develop 1-2 days after the bacteria enters the gut, but they can start in as little as a few hours and take as long as 3-4 weeks.
Symptoms often include diarrhea, vomiting, fever, stomach cramps and feeling sick. Symptoms usually last 1-2 days, but can last for up to a week.
