"The groundwork of all happiness is health." - Leigh Hunt

Heat, humidity, salmonella: unfortunately all of them go together

September 4, 2024 – The World gets hotterand the air becomes more humid. And that's an ideal recipe for more people to get sick from contaminated food Salmonella and other bacteria.

Jeri Barak, PhD, a professor within the department of plant pathology on the University of Wisconsin-Madison, said there can be “increasing periods of high humidity” as climate change continues to affect our planet, leading to more frequent and frequent consequences will result in quite a few cases of bacteria infected plants.

This can include the regular products you purchase at your local food market. If produce is infected, why should we eat it? According to Barak, avoiding infection will not be easy, and seemingly healthy plants present in stores could contain salmonella.

“Healthy plants can suffer from water stagnation” as heavy rains grow to be more frequent with climate change, she said. “Even though the plant is healthy, salmonella can penetrate the plant’s apoplast – the interior of the leaf – where it is protected from ultraviolet light.”

Barak led a study published in Applied and Environmental Microbiology It found that the number of Americans becoming sick from food-borne bacteria – already 1.2 million per year – will increase due to climate change.

The data reported in the study – along with previous research by the study authors – examines how plant disease and host infection by a plant pathogen can influence the survival and persistence of Salmonella on or in plants.

The study found that increasing humidity – a result of a warmer atmosphere due to climate change – increases the ability of salmonella to survive in raw materials. The study also found that high humidity could help other bacteria that live in the guts of animals and humans – such as: E.coli and Yersinia, along with Salmonella – survive in grain fields and cause infections.

A salmonella infection can cause diarrhea and stomach pain. The bacterium is found in the intestines of animals and is usually transmitted to humans through the consumption of food contaminated with animal feces.

In the event of a sudden infection, a sufficient amount of the bacteria is able to overcome the defenses of your stomach acid and immune system. The bacteria invade and destroy the cells lining the intestinal tract, preventing the body from absorbing water as well, leading to stomach cramps. The water then leaves your body in the form of diarrhea.

Although the thought of salmonella When people conjure up images of raw, infected meat or chicken, the most common way to become infected is by eating contaminated fresh produce. Salmonella can also survive on many different agricultural crops and remain in the soil for long periods of time.

Creating the perfect environment for plant diseases

Efforts to control salmonella in the field or before food reaches consumers have been mixed.

Sterilization methods to stop germs from multiplying include ultraviolet (UV) light. However, because they are protected when they enter the water-logged leaf, their growth is not blocked by UV radiation.

A common threat to leafy green production is Avoid Xanthomonas hortorum pva bacterium that causes spots on lettuce, a disease that affects the quality and yield of lettuce. Sometimes they can be seen as small dead spots on lettuce leaves a few days after infection, which later coalesce into larger spots.

Bacterial leaf spot was first described in 1918 after an outbreak in lettuce fields in South Carolina and threatens lettuce production worldwide. Several outbreaks have occurred over the last century, prompting researchers to study and better understand the interaction between this pathogen and plants.

In this latest study, researchers sought to determine whether the ability of Salmonella to survive in food is affected by humidity or by the timing of bacterial leaf spot progression.

The researchers found that bacterial leaf spot infection can affect the success of Salmonella in the plant. If the bacterial leaf spot infection occurs too early, the plant's defenses slow down the spread of salmonella. If the infection occurs too late, the plant is so heavily infected that salmonella no longer has much room to grow and survive.

It is a fascinating, complex, yet troubling interplay between host and pathogen that threatens food security not only in the United States but worldwide.

Impact of climate change on food security

Other commonly consumed foods around the world – particularly rice – may be affected by climate change. Successful rice cultivation depends in part on its resistance to possible bacterial diseases that could affect the crop. As better conditions are created around the world for the increase in bacterial plant diseases, production problems and deteriorating growing conditions arise, leading to price increases and supply shortages.

“Food prices could rise due to climate factors,” Barak said. “There is less food available… Some countries rely on imported food, and producing countries may decide not to export that food because they want to keep it for their own populations.”

Areas that once produced food may no longer be viable due to climate change, especially in tropical or subtropical areas. The climate will simply no longer be suitable for food production and will endanger food security.

Reducing the risk of foodborne illness

Higher rates of plant disease are a risk factor for contamination with human pathogens such as Salmonella.

Plants can be bred for resistance to these diseases.

“Most of the time we breed for resistance when the diseases cause significant crop yield losses, but we take it one step further… a foodborne illness risk factor,” Barak said. “Controlling food waste and breeding plants to resist plant pathogens could be one way to increase food safety.”

The agricultural industry often overuses antibiotics and chemicals against bacteria that contaminate food or animal feed. This can cause bacteria to become resistant to antibiotics over time. This is a growing concern for microbiologists and infectious disease specialists around the world, as new and safer solutions are urgently needed before all our usual weapons against bacteria – mainly antibiotics – become useless.

In fact, this has been observed for years. Many in the field of microbiology I warned against an antimicrobial resistance crisis, the principal reason behind which is the misuse and overuse of antibiotics in animals and plants. In theory, this might worsen as climate change increases the chance of foodborne illness and requires even greater use of antimicrobials in our food production.

Although Barak said she hasn't seen any evidence of antibiotic-resistant strains in Salmonella to this point Bacteria, she and her team analyzed data collected by the CDC over the past 10 years National Center for Emerging and Zoonotic Infectious Diseases. They focused on illnesses, hospitalizations and deaths from salmonella outbreaks.

They found a “significant increase in hospitalizations among people who became ill from consuming plant-based products” in comparison with those that consumed meat products, she said. “Whether it’s lettuce or nuts or seeds or alfalfa sprouts.”