This is Steve Ember with the VOA Special English Agriculture Report.

Researchers say extra vitamin E fed to turkeys appears to help control infections from listeria. People who eat foods that contain this bacteria can get listeriosis.

This disease is especially dangerous to pregnant women, newborn babies and people with weakened defenses. The United States has more than 2000 cases of listeriosis each year. 500 people die from it.

Some cases have been linked to poultry products that have not been cooked enough. The researchers found that vitamin E improved the ability of turkeys to fight the growth of listeria. The findings could help other meat industries as well.

Irene Wesley led the study for the United States Department of Agriculture. Researchers from Iowa State University and the University of Arkansas also took part. The findings appeared in Poultry Science magazine earlier this year.

Vitamin E is found in oils from vegetables, grains and animals. It helps protect some kinds of fatty acids that are necessary for healthy cells. Vitamin E helps prevent oxygen from combining with these fats to cause damage to cells.

Turkeys need vitamin E for normal development. But the scientists added extra amounts to the diet of two groups of turkeys. The birds were one day old. Two other groups were not given any extra vitamin E. After six weeks, the researchers infected all the young turkeys with listeria. The scientists then tested the birds for the presence of the bacteria over a period of time.

The results showed that the birds that received extra vitamin E did not get infected as often as the others. The birds that received the largest amount had the lowest number of infections.

The scientists say vitamin E has a similar effect on chickens. They say chickens and turkeys that receive added vitamin E develop more infection-fighting cells called lymphocytes. The increased number of these cells appears to also help protect against other diseases that can be carried by birds.

Earlier tests at Iowa State showed that extra amounts of vitamin E can improve the quality of meat as well, and keep it fresh longer.

The scientists continue tests. They want to see if vitamin E can stop other dangerous bacteria that can enter food. They are testing it against salmonella and campylobacter.

This VOA Special English Agriculture Report was written by Mario Ritter. This is Steve Ember.