KEY POINTS:
Germ warfare could be brought into play to protect people from food poisoning.
Researchers at the Institute of Environmental Science and Research are studying friendly viruses that attack common food-poisoning bugs such as salmonella.
They hope to reduce the need for preservatives and other chemicals used to keep salami and many other kinds of foods bug free.
New Zealand is estimated to have well over 100,000 cases of food-based infectious disease each year, costing the country more than $55 million.
ESR scientists have isolated several new kinds of viruses - called "phages" - which infect salmonella and E. coli, both bacteria.
Phages have been found in numerous foods and even the mouth: anywhere bacteria is found, phages are thought to be present as well.
"It's what you can regard as a mutual arms race," ESR senior scientist Andrew Hudson said last night. "The bacteria will mutate to resist phages and phages will counter-mutate to attack the resistant ones."
Dr Hudson and colleagues in Christchurch have done preliminary experiments showing that some phages are able to control harmful bacteria in food.
"Basically if you can get enough phages stuck to the outside of the bacterial cell, because they have mechanisms for making holes in cell walls, they can kill the cells," he said.
The ESR phage research programme has been under way for four years, but it could take many more to produce commercial phage food-safety treatments.
Dr Hudson said a treatment to control listeria - another food-poisoning bacteria - was available in Europe and had been approved for use in the United States. US researchers had also tested phages to control salmonella on apples and melons.
Many scientific hurdles needed to be overcome before phages could become a viable food-safety treatment.
"There's still a lot of work to go and consumers may not like having phages in their foods."
Some see phages as a clean, green alternative to chemical treatments.
Alison White, co-convener of the Safe Food Campaign, welcomed the research and said: "It sounds promising, especially if we can do without questionable chemical preservatives in our food and hopefully without adverse consequences."
