A Salmonella outbreak that has been puzzling health officials has officially been linked to red onions from a company based in California.

According to CBS News, the FDA has announced that Thomson International Inc., located in Bakersfield, California, was likely the source of an outbreak of the illness in recent weeks. Due to the link to red onions, all varieties that could have been contaminated are being recalled, including white, yellow and sweet onions. While the official statement from the FDA warns that consumers, retailers and restaurants should not eat, sell or serve onions from the company, it did not specify where consumers may need to watch to see if their onions are supplied by Thomson.

The outbreak had previously baffled the Centers for Disease Control and Prevention, with the outbreak reportedly affecting hundreds in over 23 states, including Idaho, South Dakota, North Dakota, Arizona, Virginia, Florida, Nebraska, Maine, Oregon and Utah. That number, CBS reports, has since grown to over 30 states, with 396 people sickened and nearly 60 hospitalized since the outbreak began in July.

It is believed this same outbreak has also spread to Canada, which is launching its own investigation.

This outbreak is the second to affect the United States in recent weeks, with another linked to backyard poultry operations also identified. That particular outbreak is believed to have sickened 938 people in 48 states, leading 151 to be hospitalized and causing one death, ABC News Raleigh reports. That outbreak began in May.

Symptoms of Salmonella include diarrhea, fever and stomach cramps, and can occur anywhere between six hours and six days following exposure to the bacteria. Symptoms usually last between four and seven days.

salmonella outbreak in 23 states says CDC salmonella outbreak in 23 states says CDC Photo: WikiImages - Pixabay