Preservatives are commonly used to keep food fresher for longer, but artificial preservatives have gained a bad reputation regarding their negative health effects. Instead, scientists from Nanyang Technological University (NTU) have found a plant-based food preservative that is more effective than artificial preservatives.

The organic preservative comprises naturally occurring substances known as ‘flavonoids’, a diverse group of phytonutrients found in almost all fruits and vegetables. NTU researchers implanted the flavonoid-producing mechanism from plants into baker’s yeast to create flavonoids with strong antimicrobial and antioxidant properties that inhibit bacterial growth.

“This organic food preservative is derived from plants and produced from food-grade microbes, which means that it is 100% natural. It is also more effective than artificial preservatives and does not require any further processing to keep food fresh,” said Professor William Chen, Director of NTU’s Food Science & Technology program.

He explained that flavonoids extracted directly from plants need to be further processed to be antimicrobial, while flavonoids produced from yeast do not require this.

Led by Chen, a team of scientists compared how the organic and artificial preservatives performed using meat and fruit juice samples at room temperature (about 23oC). While it only took six hours for the food samples with artificial preservatives to succumb to bacteria contamination, the organic preservative kept samples fresh for two days without refrigeration.

“This may open new doors in food preservation technologies, providing a low-cost solution for industries, which will in turn encourage a sustainable food production system that can produce healthier food that stays fresh longer.”

This research follows mounting concerns about the effects of artificial preservatives on the body. For example, sodium nitrate and nitrite are used as preservatives and add colour and flavour to processed meats, but they may interfere with thyroid hormone production and have been linked to bowel cancer.

The NTU research team aims to further develop the new food preservative so it can be used in all packaged food products. The findings were published in the journal Food Chemistry.