Soy can be used as an antibacterial agent to fight food-borne illnesses, University of Guelph study finds

Researchers at the University of Guelph have discovered soy can naturally protect people from food-borne illnesses like listeria, and does it better than synthetic-based agents that are currently widely used in the food industry.

Soybean derivative can tell good bacteria from the bad, researchers find

Components in soybeans appear to stop or slow the growth of bacteria that cause food-borne illnesses, such as listeria, new research from the University of Guelph has shown.

Soy has essential amino acids, protein and is a good source of fiber and calcium.

But, it turns out, soy also has the ability to naturally protect people from food-borne illnesses like listeria.

A new study from the University of Guelph has found soy can limit the growth of some bacteria, such as listeria and pseudomonas, and it does it better than chemical-based agents.

"Current synthetic-based, chemical-based anti-microbial agents kill bacteria indiscriminately, whether they are pathogenic or beneficial," researcher Suresh Neethirajan said.

The body – and in particular, the intestines – need good bacteria to properly process the food we eat.

The compounds in soybeans, however, do not kill off all bacteria, just the bad ones, Neethirajan said.

Natural way to curb bacteria

Soybean derivatives are already used in a variety of products including canned foods, cooking oils, meat alternatives, cheeses, ice cream and baked goods. 

Neethirajan, an engineering professor and director of the BioNano Laboratory at the university, said those with soy allergies need not worry about soy being used to prevent bacteria growth.

He said their method isolates the active component of the soybean from the protein that causes allergic reactions. The soy isoflavones that are chemically similar to estrogen are also weeded out.

What is left is a compound that naturally stops the bad bacteria.

Suresh Neethirajan is an engineering professor and the director of the BioNano Laboratory at the University of Guelph. (University of Guelph)

Neethirajan said the problem with the synthetic additives that are currently used is that they can cause health problems.

"You do need good bacteria, beneficial bacteria, in our intestines to be able to properly process the food we eat, so that's why a lot of antibiotic food preservatives, which are made of synthetic chemicals, have ... side effects such as stomach cramps, diarrhea, bloating, gas," he said.

"Because of the selective specificity [by soy] towards inhibiting the pathogenic bacteria compared to beneficial bacteria, it will eliminate some of the health issues associated with the current synthetic-based food preservatives."

Different varieties, different results

The research isn't just good news for those concerned about the additives to their food – it may also be a boon for soybean producers.

Neethirajan is now working to identify which varieties of soybeans are best at preventing bacteria from growing.

"That way we could help the producers of soybeans to choose which varieties they want to grow towards specific end applications," he said.

He is also working on a method to extract the specific components that involves "using water at very high pressure to be able to separate these … specific components, so it's very environmentally friendly from the manufacturing perspective."

Neethirajan's study will appear in the July edition of the journal Biochemistry and Biophysics Reports.

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