The enzyme xylanase is used by some farmers to accelerate growth in poultry. It is also used in bread making.
A report in New Scientist magazine says Dr Fresie Fernandez, a microbiologist from the University of Bristol, has discovered that the enzyme can dramatically limit numbers of the bacterium Campylobacter jejuni in chicken's guts.
Almost all chickens carry the bacteria without any ill effects.
But if humans eat under-cooked chicken contaminated with the bug, they can become seriously ill.
The bacteria thrive in the slimy mucus that lines the intestines, causing cramps and diarrhoea.
Dr Fernandez and her colleagues fed campylobacter-infected chicks wheat laced with small amounts of xylanase.
In chickens, the enzyme makes the mucous lining of the stomach thinner and less sticky.
This allows nutrients to be absorbed more effectively, helping the birds to grow.
But Dr Fernandez also found that after a month, the number of bugs in the chickens' guts fell by up to 99%.
The researchers suspect that the bugs are flushed from the chickens' systems more quickly when the mucous lining is thinner and more fluid.
Dr Fernandez thinks that chicken farmers could use xylanase as a simple way to make poultry meat much safer to eat without having to use antibiotics.
She said: "I think that all companies should use this."
A spokesman for the Food Standards Agency told BBC News Online: "We would welcome in principle any research into controlling campylobacter in poultry.
"However, proper handling and cooking is still the best way to reduce instances of food poisoning from this bacteria."