Salmonella enterica bacteria become more virulent and therefore better at causing disease in the micrograity environment of space.
Salmonella 101: What you need to know
01:09 - Source: CNN
CNN  — 

A salmonella outbreak caused by onions is expanding and has infected 640 people from 43 states. At least 85 of them have been hospitalized, the Centers for Disease Control and Prevention said.

“If you don’t know where your onions are from, don’t eat, serve, or sell them or any food prepared with them,” the CDC said Friday.

The Food and Drug Administration has warned consumers not to eat onions from Thomson International Inc. The advice applies to red, white, yellow, and sweet onions.

Some of the onions were sold at stores including Walmart, Kroger, Fred Meyer, Publix, Giant Eagle, Food Lion, and H-E-B, under a variety of brand names, the CDC said.

Several companies have recalled onions and foods made with recalled onions like chicken salad, macaroni salad, fajita stir-fry, pizza and diced raw onions, including Taylor Farms and Giant Eagle.

The CDC said people should check their homes for the recalled products and throw away the affected items.

“Do not eat them or try to cook the onions or other food to make it safe,” the CDC said.

Signs of salmonella infection include diarrhea, fever and stomach cramps between six hours and six days after exposure to the bacteria, the CDC said. People are usually sick for between four and seven days. Those under age 5, those over 65 and people with weakened immune systems are more likely to experience severe illness.

In some cases, the infection can spread from the intestines to other parts of the body and require hospitalization.

The CDC is urging anyone with symptoms of salmonella poisoning to contact a doctor, write down what they ate the week before they became sick, report the illness to the health department and communicate with health investigators about their illness.

Infections have been reported in Arizona, California, Colorado, Florida, Indiana, Illinois, Idaho, Iowa, Kansas, Kentucky, Maine, Maryland, Minnesota, Missouri, Montana, Nebraska, Nevada, New York, North Carolina, North Dakota, Ohio, Oregon, Pennsylvania, South Carolina, Tennessee, Texas, Utah, Virginia, Wisconsin and Wyoming.

A complete list of affected states is on the CDC’s website.