Most Cases of Salmonella Infections Come from Chicken and Vegetables, A New Study Finds. But Don’t Throw Out the Chicken Soup Just Yet!

A recent study cites chicken and vegetables as the most common source of Salmonella infections in the United States. The study also explores the reason most illnesses are not connected to known outbreaks. They blame outdated analytical methods.

Whole genome sequencing and machine learning techniques can perform these tasks with more robust results. This approach is what led researchers to the aforementioned conclusion.

Salmonella Infections

Salmonella bacterial infections are a leading cause of foodborne illness and related hospitalizations in the United States. In fact, the Centers for Disease Control and Prevention (CDC) estimates that Salmonella infections are responsible for 1.35 million illnesses each year. And while food is a common source of Salmonella illness, only about 5% of those infections are traced back to a known outbreak.

This complicates tracing individual infections to a specific source.

Common sources of Salmonella infections include food, drinking water, environmental sources (soil, water, etc.), contact with animals, and other infected people.

That leaves a lot of options with little to go on.

And so, a study was formed.

The Study

The study, “Attribution of Salmonella enterica to Food Sources by Using Whole-Genome Sequencing Data,” was recently published in the CDC’s journal, Emerging Infectious Diseases. Authors include scientists from the CDC, the U.S. Food and Drug Administration (FDA), and the United States Department of Agriculture (USDA).

These scientists compiled a dataset of nearly 20,000 Salmonella samples from food and animal sources, along with existing data about the samples.

The majority of the samples were from domestic sources, but some imported products were included. This was considered to make it “broadly representative of domestic food sources.”

This data was used to “teach” the program what Salmonella samples were attributed to each food.

Researchers used 6,470 Salmonella samples from human infections where the source was unknown (and no international travel history).

Random Forest Learning Algorithm

They put genetic data from samples into a software called SPAdes and used what is called “Random Forest machine learning algorithm.” This method is a play on the term “decision tree” where answers to each question poses another question until a final decision is made.

The Random Forest method involves many of these single decisions trees, but the results combine into a single answer.

An effective method for this type of consideration.

Using this data, the model predicted infection sources for human cases with >50% probability. For those that the model was not “certain” of, the case was placed in the “unknown source” category.

Results

Of the 18,661 food samples, chicken and vegetables were the highest attributable foods.

Chicken 31%

Vegetables 13%

Turkey 12%

Pork 11%

When looking at human cases, the model attributed 46% of Salmonella infections to chicken and 27% to vegetables.

Further driving home the increased risk of chicken and vegetables.

Where Does It Go from Here?

The study proved the effectiveness of whole genome sequencing combined with a Random Forest machine learning algorithm to accurately identify food sources of Salmonella infections in the US. With chicken and vegetables identified as the primary contributors of these infections, potential “targeted regulatory and public health strategies” could help prevent or catch contamination events early.

“This genomic approach offers significant improvements over traditional methods,” said study authors. This information can provide “detailed insights crucial for food safety policy, routine surveillance, and outbreak management.”

Contributors indicate that further research should include increased sample diversity and geographic representation. They suggested that non-food sources, like animal samples, could strengthen the model’s precision.

How Bad Are Salmonella Infections?

Salmonella infection symptoms can begin anywhere from six hours to six days after exposure.

Most people experience diarrhea, fever, and stomach cramps that last about a week (four to seven days).

Higher Risk Groups

Certain groups of people have conditions or susceptibilities that make them more likely to become sick if exposed, and experience more severe symptoms if infected.

Those more vulnerable to Salmonella infection include:

• Children under 5 years of age
• Infants (children under 12 months of age) that are not breast fed
• People taking certain medications such as stomach acid reducers

Those more likely to experience sever symptoms include:

• Infants
• Older adults (65 years and older)
• People with a weakened immune system

While most people do not need medical intervention and are not prescribed antibiotic treatment, those in the higher risk group are more likely to receive treatment.

In some cases, complications may arise from infection.

Salmonella Complications

Most of the time Salmonella bacteria are limited to the intestinal tract. But in some cases, bacteria can breach the intestinal wall and enter the bloodstream. When this happens, bacteria may infect the urinary tract, blood, bones, joints, and even the nervous system.

Common Salmonella complications include bacteremia, irritable bowel syndrome, and reactive arthritis that can affect other parts of the body.

Does This Mean We Should Avoid Chicken Soup?

While chicken and vegetables were the biggest sources of Salmonella infections identified in the study, that doesn’t mean you should avoid those ingredients altogether. Whether apart or combined in a soup, there are things you can do to help protect yourself from foodborne illness.

Wash Your Hands

This is always the top of the list. Clean hands help prevent spreading germs. Use warm soapy water and wash your hands before you begin cooking, before you eat, and anytime you handle or come in contact with raw meat or something potentially contaminated.

Wash Your Veggies

Always wash your fruits and vegetables. A good rinse or scrub (for harder skinned produce) can remove potential germs and chemicals before they make it into your meal.

Cook to Safe Minimum Internal Temperature

Heat is an effective way to kill germs. Follow the USDA’s minimum internal temperature chart to ensure that you cook food effectively hot enough to kill those lurking germs. Always use a food thermometer for an accurate reading.

Have You Fallen Sick from a Salmonella Outbreak?

If you have been impacted by a Salmonella outbreak and wish to make a legal claim, The Lange Law Firm, PLLC has a Salmonella lawyer that can help.

The Lange Law Firm, PLLC has successfully represented cases just like yours and won millions of dollars in food poisoning and products liabilities lawsuits.

Reach out by calling (833) 330-3663 or send us an email for a free, no obligation consultation to go over the details of your situation with you.

Don’t wait. Call today to get the justice you deserve.

By: Heather Van Tassell (contributing writer, non-lawyer)