Key Takeaways

• Most salmonella illnesses are caused by a few very dangerous strains of the bacteria
• One of the most common strains, Salmonella Kentucky, causes fewer than 1% of illnesses in humans
• Three other strains cause as many as four out of five cases of Salmonella food poisoning, researchers found

WEDNESDAY, July 17, 2024 (HealthDay News) -- Most salmonella outbreaks linked to poultry are caused by just a few strains of the diarrhea-causing bacteria, a new study finds.

There are more than 2,600 different types of salmonella bacteria, but only three strains are most likely to cause illness in humans, researchers report.

Interestingly, one of the most common types found in U.S. chicken -- Salmonella Kentucky -- causes less than 1% of human cases of illness, researchers said.

On the other hand, 69% to 83% of illnesses were caused by the salmonella strains Enteritidis, Infantis or Typhimurium, according to a report published recently in the Journal of Food Protection.

These results support a new tack being taken by the U.S. Department of Agriculture (USDA) to shift its tracking and detecting to the most dangerous salmonella strains, said researcher Matt Stasiewicz, an associate professor of food science and human nutrition at the University of Illinois Urbana-Champaign.

“Over the last 20 years, the poultry industry has done a really good job of lowering the frequency of salmonella in poultry,” Stasiewicz said in a university news release. “However, the number of people who are getting sick from these pathogens hasn’t declined.”

“The U.S. Department of Agriculture is considering changes to how they regulate salmonella based on level and serotype [strain], and our research supports those efforts,” Stasiewicz added.

Salmonella bacteria cause about 1.3 million infections, 26,500 hospitalizations and 420 deaths in the United States every year, according to the U.S. Centers for Disease Control and Prevention.

The Healthy People 2030 initiative calls for reducing salmonella infections to fewer than 11.5 per 100,000 cases per year. To reach this goal, illnesses must drop by 25% by the end of the decade, the USDA says.

The analysis of USDA data revealed there are about two Salmonella cases for every 1 million servings of chicken consumed in the U.S., researchers report.

In all scenarios, the risk of salmonella poisoning was concentrated in a few chicken products carrying high levels of highly infectious types of the bacteria, results show.

The next step is to figure out how to specifically target these nasty salmonella strains, the researchers said.

Different potential approaches include using statistics to monitor salmonella cases in poultry processing, holding batches of poultry products until they’ve been thoroughly tested or vaccinating chickens against the worst strains, researchers said.

“These findings support the USDA’s initiative to shift regulation towards high-level, high-risk contamination events rather than frequency of detection,” Stasiewicz said. “I hope this will help consumers understand it's a good strategy that’s designed to protect public health.”

“The layperson could think the new regulations are letting the industry off the hook, because they only target specific pathogens and allow contaminated chicken to get through production,” Stasiewicz said. “But it makes sense to focus on the strains that are actually making people sick.”

More information

The U.S. Centers for Disease Control and Prevention has more about salmonella.

SOURCE: University of Illinois Urbana-Champaign, news release, July 15, 2024

What This Means For You

To prevent salmonella infection, people should wash their hands after handling raw poultry, make sure poultry and meat is cooked well, and wash vegetables and fruits thoroughly before eating them.