According to researchers at RMIT University in Melbourne, Australia, they have shown how a natural bacteria-killing compound in Nem Chua, a fermented pork snack, could be used to keep food fresh for longer.
The fermented pork snack, Nem Chua, is eaten raw but does not cause food poisoning when prepared correctly. This is because friendly bacteria that thrive in the fermented meat make a special compound that destroys more dangerous bacteria.
A team of RMIT researchers was inspired to investigate Nem Chua for its potential antibacterial properties after travelling to Vietnam and observing people eating the raw meat snack without getting sick, despite the hot and humid climate.
They subsequently discovered a new type of bacteria-killing compound in Nem Chua called Plantacyclin B21AG: one of a group of compounds known as bacteriocins, which are produced by bacteria to destroy rival bacterial strains. Bacteriocins form holes in the membranes of target bacteria. This causes the contents of the cell to leak out - effectively killing the bacteria. Only one bacteriocin - Nisin, which came to market in the 1960s - is currently licensed for use as a food preservative, but this compound is temperature and pH sensitive limiting its use.
According to the researchers, the Nem Chua-derived compound is more robust than Nisin and is effective against a wide range of bacteria even after exposure to a range of environments typical in food processing.
It can survive being heated to 90C for 20 minutes and remains stable across high and low pH levels, they said, adding that the compound can also destroy a range of disease-causing organisms commonly found in food including potentially life-threating Listeria, which can survive refrigeration and even freezing.
The discovery could help address the twin global problems of food waste and food-borne illnesses, the researchers said.
Food waste is a global issue that costs around $US680 billion annually in industrialised countries, consumes nearly a quarter of the water used in agriculture and produces 8% of global greenhouse emissions. Food-borne diseases like Listeria or Salmonella, meanwhile, affect millions each year and can be life threatening for pregnant women, older people and those who are immunocompromised.
Potential to produce at scale
Co-lead researcher Professor Oliver Jones added there is potential to make the bacteria-killer at industrial scale to capitalise on changes in consumer habits have led to a greater demand for natural alternatives to artificial food preservatives.
"Scientists have known about these bacteria-killing compounds for many years but the challenge is to produce them in large enough quantities to be used by the food industry," said Jones, Associate Dean of Biosciences and Food Technology at RMIT.
"The Nem Chua compound is colourless, odourless, tasteless and very resilient.
"Through this new research, we've identified the right growth conditions that would enable us to make it in large amounts, potentially at industrial scales.
"With further development, we hope this could be an effective, safe and all-natural solution for both food waste and food-borne disease."
Researchers at RMIT's School of Science have begun experimenting with methods to further purify the compound and are planning to incorporate it into test food products.