Trader Joe’s has recalled packaged herbs linked to a multistate salmonella outbreak, the grocery chain announced this week.

The product, Infinite Herbs organic basil, was sold in 2.5-ounce clamshell containers from Feb. 1 to April 6 in 29 states as well as in Washington, D.C., Trader Joe’s said on Wednesday. 

There have been 12 reports in seven states of people infected with salmonella, an organism that can cause serious or fatal illness, according to federal officials. One person was hospitalized.

“Seven of eight cases with information available reported exposure to fresh organic basil purchased from Trader Joe’s before becoming ill,” the Food and Drug Administration said on its website, adding that “traceback data” it had collected determined that Florida-based Infinite Herbs, LLC, had supplied the basil to Trader Joe’s.

Grego Berliavsky, the head of Infinite Herbs, said Wednesday that the company had voluntarily recalled the product. 

“I am heartbroken at the thought that any item we sold may have caused illness or discomfort,” he said in a statement. “We simply will not rest until we can once again be confident in the safety of this product.”

Berliavsky added that customers should check their freezers for the basil.

“Fresh basil naturally wilts and expires after five to seven days, so we are confident that the recalled basil is no longer available for sale,” he wrote. “However, if you have food in your freezer that includes Infinite Herbs organic basil purchased between February 1 and April 6, do not consume it.”

The basil had been sourced from a single farm, which is no longer in production, according to Berliavsky.

“We are working with the farmer to conduct an internal investigation of the food safety practices. Through this investigation, our goal is to determine the cause of this recall and apply measures to prevent it from happening again,” he wrote.

Symptoms of salmonella include diarrhea, fever and stomach cramps, according to the Centers for Disease Control and Prevention. The symptoms usually start 6 hours to 6 days after infection, and while most people recover within a week without antibiotics, some may need medical treatment. The CDC says that children younger than 5, adults 65 and older and individuals with weakened immune systems are more likely to get serious salmonella infections, but anyone who has severe diarrhea, bloody stools, a fever higher than 102 degrees or prolonged vomiting may need antibiotics or to be hospitalized.

Salmonella causes about 1.35 million infections, 26,500 hospitalizations and 420 deaths in the United States every year, according to the CDC. But official counts are likely an underestimate because most people recover without seeking medical help or without a confirmed diagnosis, said Barbara Kowalcyk, an associate professor of exercise and nutrition sciences at the George Washington University Milken Institute School of Public Health.

Infections come from a variety of sources, including consuming contaminated food and water or touching infected animals and their environments.

In rare cases, salmonella or its toxins can enter the bloodstream, causing serious illnesses, death or long-term conditions like arthritis, Kowalcyk said.

“One of the things in food safety that we try to do is make people aware that it’s not just this bad tummy ache,” she said. “There are other health implications.”

Salmonella is not visible and cannot be smelled or tasted, Kowalcyk said. Trader Joe’s instructed customers to discard the packaged basil or to return it for a full refund. 

The FDA said infections have been reported in Florida, Georgia, Minnesota, Missouri, New Jersey, Rhode Island and Wisconsin; the product was also distributed in Alabama, Connecticut, Washington, D.C., Delaware, Iowa, Illinois, Indiana, Kansas, Kentucky, Massachusetts, Maryland, Maine, Michigan, North Carolina, Nebraska, New Hampshire, New York, Ohio, Pennsylvania, South Carolina, Tennessee, Virginia and Vermont.

The news comes a month after another large Trader Joe’s recall involving potential salmonella contamination. In March, the grocer recalled cashews sold in 16 states. No illnesses were reported in that instance. Earlier in March, Trader Joe’s recalled steamed chicken soup dumplings that federal officials said were potentially contaminated with “hard plastic from a permanent marker pen.”