- Bacteria-killing compound discovered in Nem Chua, a fermented pork snack
- Toxic to bacteria but safe for humans, it’s a natural alternative to artificial food preservatives
- New study reveals ideal growth conditions to potentially make the bacteria-killer at industrial scales
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.
Now researchers at RMIT have shown how this natural bacteria-killing compound could be used to keep food fresh for longer.
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 affect millions each year and can be life threatening for pregnant women, older people and those who are immunocompromised.
Co-lead researcher Professor Oliver Jones said 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.”
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.
The team, led by Professor Andrew Smith (now at Griffith University) and Dr Bee May, discovered a new type of bacteria-killing compound in Nem Chua.
Plantacyclin B21AG is 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.
The problem is most bacteriocins only work against one or two types of bacteria and they are not very stable in different environmental conditions.
Only one - Nisin, which came to market in the 1960s - is currently licensed for use as a food preservative, in a market estimated to be worth more than $US513 million in 2020, but this compound is temperature and pH sensitive limiting its use.