WASHINGTON – Federal health officials renewed warnings Wednesday that raw or even lightly cooked sprouts can cause serious food poisoning.

The Food and Drug Administration for years has warned Americans not to eat raw alfalfa, clover and other sprouts after hundreds of reports of salmonella and E. coli infections. The FDA reissued its warning because of a late-summer E. coli outbreak in California caused by alfalfa sprouts.

While the young, elderly and people with weak immune systems are most prone to serious infections when exposed to salmonella or E. coli, the food-poisoning germs can cause diarrhea, nausea, abdominal cramping and fever for several days even in healthy people.

The FDA said homegrown sprouts should not be presumed safe because many outbreaks have been attributed to contaminated seed.