The U.S. Centers for Disease Control and Prevention (CDC) has issued a food safety alert for a multistate outbreak of E. coli and salmonella infections that has sickened 55 people across 15 states, most of whom reported eating alfalfa sprouts before falling ill.

The outbreak has so far resulted in four hospitalizations, and no deaths have been reported, according to the agency.

The affected alfalfa sprouts were produced by Everything Sprouts and sold under the Calco and Everything Sprouts brands at retailers and grocery stores. Customers are advised to throw away or return any of the affected products and to wash any surfaces that may have come into contact with the sprouts.

Sprouts are a recurring source of foodborne illness outbreaks because bacteria can cling to seeds, and the warm, moist conditions used to germinate them allow any germs present to multiply rapidly. The CDC has long advised that children, older adults, pregnant people and those with weakened immune systems avoid eating raw sprouts of any kind, noting that thorough cooking is the only reliable way to kill harmful bacteria they may carry.

Outbreak Investigation

Along with the CDC, public health and regulatory officials in several states and the U.S. Food and Drug Administration (FDA) are investigating the outbreak, which involves three strains of E. coli and one strain of salmonella.

Of those sickened, 46 people were infected with E. coli, seven with salmonella, and two with both. The CDC said that some people were infected with more than one strain of the infections.

Minnesota recorded the majority of illnesses with 21 cases, followed by Wisconsin with 17. Two people were sickened in each of New York, North Dakota, North Carolina and Florida, while one illness was reported in each of Washington, South Dakota, Iowa, Kansas, Indiana, Pennsylvania, Michigan, New Hampshire and South Carolina.

The illnesses began in late May and continued through Aug. 8.

Symptoms and Medical Guidance

E. coli symptoms include stomach cramps, bloody diarrhea and nausea, while salmonella symptoms involve diarrhea, stomach cramps and fever. According to the CDC, E. coli symptoms typically begin three to four days after exposure, while salmonella symptoms usually start six hours to six days after infection and last four to seven days.

The CDC urged people to see a doctor immediately if they experience any of the following:

• Diarrhea and a fever higher than 102 degrees
• Bloody diarrhea
• Diarrhea lasting more than two days
• An inability to keep anything down
• Signs of dehydration, including not urinating much, a dry mouth and throat, and feeling dizzy when standing up

Broader Context

The alfalfa sprouts outbreak comes amid several other food-borne outbreaks reported recently that have been linked to jalapeños, iceberg lettuce, eggs and blueberries.

Health authorities note there is typically a lag between when a person becomes ill and when the case is confirmed and reported, as laboratory testing and patient interviews must be completed, so outbreak investigations of this kind generally unfold across multiple public updates.