PRINCE.EDWARD.ISLAND (CBC) - Kids, the elderly, pregnant women and those with weakened immune systems are advised not to eat raw or undercooked sprouts, federal health officials said Wednesday.

Health Canada and the Canadian Food Inspection Agency sent out the reminder saying sprouts, such as alfalfa and mung sprouts, are a popular and healthy snack and ingredient.

Onion, radish, mustard and broccoli sprouts, not to be confused with the actual plant or vegetable, are also options.

But these sprouts may carry harmful bacteria such as salmonella and E. coli O157:H7, also known as hamburger disease, that can lead to serious illness.

In the fall of 2005, more than 648 cases of salmonella sickness were reported in Ontario, the largest recent outbreak in Canada.

"Children, the elderly, pregnant women and those with weakened immune systems are particularly vulnerable to these bacteria and should not eat any raw sprouts at all," the advisory said.

"They should also avoid eating cooked sprouts unless they can be sure the sprouts have been thoroughly cooked."

Healthy adults who eat sprouts should take precautions, such as:

Symptoms from salmonella usually occur 12 to 36 hours after eating contaminated food, while symptoms from E. coli O157:H7 the strain that killed seven people who drank contaminated water in Walkerton, Ont., in 2000 can occur within two to 10 days. In extreme cases, the strain can also lead to acute kidney failure.

Symptoms of E. coli can include nausea, diarrhea, vomiting, fever and stomach cramps.