"It still continues to rise, even though the overall incidence of salmonella in general has fallen," said Richard Raymond, the Agriculture Department undersecretary for food safety. "It's one that we still don't have all the scientific evidence we need to know how best to attack it."

Salmonella sickens at least 40,000 people and kills about 600 every year in the U.S.

Many different salmonella bacteria make people sick, but salmonella enteritidis is one of the most common. It causes fever, stomach cramps and diarrhea, and in vulnerable people, infection can turn deadly by spreading beyond the intestine to the bloodstream.

It used to be that eggs got contaminated with salmonella on the outside, from contact with fecal bacteria. But in recent years, the salmonella enteritidis strain has been found inside intact, disinfected, grade A eggs. This type of germ contaminates eggs inside a hen's ovaries, before shells are even formed.

Now the germ is turning up in broiler chickens, the kind used for meat, according to research by the Agriculture Department published in the December issue of the Emerging Infectious Diseases journal of the Centers for Disease Control and Prevention.

Source: safe-poultry.com