Common food additive holds key to slowing down E. coli bacteria

Lawrence Goodwyn

Researchers recently found that polysorbate 80, a common food additive, renders E. coli bacteria harmless.

Alfredo Torres, UT Medical Branch Galveston researcher and UT alumnus, and Chris Waters, professor of microbiology and molecular genetics at Michigan State University, discovered that polysorbate prevents the spread of toxins of a pathogenic strain of E. coli. This specific strain was involved in a serious outbreak in Germany in 2011 that affected almost 4,000 people and caused 53 deaths. This additive stops the spread of toxins by disrupting the bacterial biofilm.

Torres said biofilms are colonies of bacteria that grow when existing cells combine with them and can attach to human intestines. E. coli can form biofilms in the intestine, where it releases a pathogenic compound called the Shiga toxin. Waters said that once the Shiga toxin enters the bloodstream it can cause kidney failure, resulting in hospitalization and even death.

“Our hypothesis is that once the E. coli gets into the biofilms, it makes more of the shiga toxin.” Waters said. “Once you add polysorbate, it breaks up the biofilm. The bacteria is still there, but it’s not making as much Shiga toxin so it becomes harmless.” 

Torres said the polysorbate 80 works by breaking up these E. coli biofilms in the intestines.

“Imagine this, if you are using soap or some detergent, essentially what polysorbate does is break up the aggregate [biofilms] like a soap,” Torres said. 

Torres said that the specific strain of E. coli he studied had such a widespread breakout in Germany because it could continuously form biofilms in the intestines and release harmful Shiga toxins. 

The Shiga toxin has also been found in American outbreaks but was easier to contain than the strain in Germany in 2011, which both persisted in the gut and also had the Shiga toxin, making it ”the worst of both worlds,” Torres said. 

Polysorbate 80 allows the host to maintain the current conditions of its intestinal microenvironment, unlike antibiotics, which can destroy all bacterial life, leaving the host with depleted gut health. 

“The exciting part of this study is not just the fact that we inhibited the bacteria, but the fact that we observed that the [deactivated E.coli], once in the intestine, doesn’t destroy anything,” Torres said.   

According to Torres, even small amounts of the food additive could slow down the hazardous effects of E. coli poisoning in humans. He said the polysorbate works because it can be administered before the bacteria causes any harm.

“The rationale behind this is once the bacteria gets in the intestine, and before it starts delivering the toxin or during the process, we can start delivering this [additive],” Torres said. 

The researchers said they still have work to do before polysorbate can be used for the public as a technique to slow down E. coli growth. 

The use of polysorbate 80 may not require any FDA approval because it’s already a legal food additive. Torres said the next step is to explore methods of administering polysorbate and find the optimal dosage for humans.