Fresh food for years with newly discovered natural preservative

By Dr. Ananya Mandal, MDAug 15 2011

Scientists have discovered a natural preservative capable of destroying a whole class of bacteria, including E.coli and listeria and now food can be made to remain fresh and last for years. There would also be no need to refrigerate produce treated with the preservative, called, bisin, which is produced by harmless bacteria.

The researchers say foods like milk; sausages and sandwiches containing the agent could be on the shelves within three years. Ready meals, opened wine and fresh salad dressing could also be safely consumed long after they were bought, say scientists.

This comes from researchers at Minnesota University in the US who found the substance from a culture of harmless bacteria, Bifodobacterium longum, commonly found in the human gut. It is the first naturally occurring agent identified that attacks so-called gram-negative bacteria such as E.coli, salmonella and listeria.

According to Dan Sullivan, a microbiologist who works at the university, “It seems to be much better than anything which has gone before. It doesn't compromise nutrient quality — we are not adding a chemical, we are adding a natural ingredient.” He and his team have patented the substance in the US.

Bisin is related to nisin, which attacks gram-positive bacteria, and is used in the manufacture of processed cheeses and meats. As such, it is generally recognized as safe and would not have to be pharmacologically tested.

It would however not be able to prevent fruit and vegetables from rotting, however, as they decompose in a different way. Further research is now ongoing, looking at exactly how good it is at stopping bacteria from growing.

This new discovery could reduce the 20 million tonnes of food waste thrown out in the UK every year. British households throw out £5 billion worth of uneaten food a year, a study has revealed.

It will also reduce the number of food poisoning cases. There were 85,000 cases last year. Salmonella was one of the biggest culprits, accounting for around one in eight of those. Up to 500 people die from food poisoning in England and Wales every year.