Plant Proteins May Reduce E. Coli on Food

Plant proteins are not only popular as a vegetarian-source of protein used in many food and drink products such as cereals, they are also being investigated for their antimicrobial properties. Given that E. coli is one of the leading causes of bacterial infections worldwide, this type of research is important.

A new study published in the Proceedings of the National Academy of Sciences showed certain genetically engineered (GE) plants high in colicins—non-antibiotic antimicrobial proteins produced by E. coli strains that kill or inhibit the growth of other E. coli strains—may be able to reduce E. coli bacteria on food.

In the current study, the researchers demonstrated very high levels of colicin expression (up to 3 g/kg of fresh biomass) in tobacco and edible plants, such as spinach and leafy beets. They applied these colicins to meat “spiked with E. coli" to kill the bacteria, and in doing so, they identified a mixture of two colicins that can efficiently kill all major disease-causing strains of E. coli. The researchers sprayed E. coli-laced pork steaks with a mixture of two types of colicins, at 4 mg of colicin per kg of meat, and found significant reductions in E. coli after just an hour.

They concluded: “Plant-produced colicins could be effectively used for the broad control of pathogenic E. coli in both plant- and animal-based food products and, in the United States, colicins could be approved using the generally recognized as safe (GRAS) regulatory approval pathway."

As IFT also reported: “The cost of the new method is less than the traditional methods used to treat meat, which often involve heat or organic acids. In addition, they believe the process is superior because, unlike these traditional treatments, colicins don’t affect the quality and taste of the meat."