At least 979 people have been infected in a salmonella outbreak linked to onions sold at stores including Walmart, Kroger, and Trader Joe's

• A salmonella outbreak linked to onions has infected at least 979 people in the US and Canada, according to health officials.
• Thomson International recalled onions that had been shipped to all 50 states in early August.
• The Thomson International recall sparked other recalls of products that may have used contaminated onions, including cheese dips, salsas, and prepared foods.

A salmonella outbreak linked to onions has infected at least 979 people in the US and Canada.

Canadian health officials said on Friday that there have been 339 cases of salmonella linked to onions from Bakersfield, California-based supplier Thomson International. As of Friday, 48 people had been hospitalized.

There have been 640 confirmed salmonella cases linked to the outbreak in the US, according to the Centers for Disease Control and Prevention. Some 85 people had been hospitalized.

Thomson International announced in early August that it was recalling red, yellow, sweet yellow, and white onions shipped since May 1 because of potential salmonella contamination. In the days since, the Thomson International recall sparked a series of recalls by other suppliers and retailers.

Some grocery chains have announced their own recalls

Giant Eagle recalled onions and other prepared foods that may have been contaminated in the outbreak. The recall affected the chain's Onion 52 brand, as well as salads, pizzas, and sandwiches. The full list of recalled prepared foods can be found here.

Publix recalled red onions packaged by Del Monte Fresh Produce sold in bulk bins in stores in Alabama, Georgia, North Carolina, South Carolina, Tennessee, and Virginia. The recall did not apply to stores in Florida.

Progressive Produce LLC issued a recall of certain red and yellow onions sold in West Coast Trader Joe's and Ralph's locations. The recall includes red onions sold at Trader Joe's stores in Arizona, California, Nevada, and Utah, sold under the brand name Pacific Gold. The distributor's recall also affected yellow onions sold in California Ralph's stores.

Other potentially contaminated products have been recalled

Taylor Foods recalled some prepackaged foods, due to contamination concerns. The recall affected certain prepared foods sold at grocery stores including Walmart and Kroger. A full list of all recalled Taylor Farms products can be found here.

Spokane Produce Inc. issued a recall for salsa products that used onions that had been recalled. The recalled salsas included the brand's "Saddlin' Up Salsa" and "Salsa Verde," with a full list of Spokane Produce's recalled products available here.

Last week, a number of retailers recalled cheese dips that used potentially contaminated onions. The recalls affected dozens of cheese dips and spreads sold between May 15 and August 6 at Kroger, Fred Meyer, Fry's Food Stores, and Smith's Food and Drug. Many of the recalled items are Murray's, Jarslberg, and deli cheese dips.

'When in doubt, throw them out'

Thomson International's original recall included onions that are sold under a variety of brand names, including:

• Thomson Premium
• TLC Thomson International
• Tender Loving Care
• El Competitor
• Hartley's Best
• Onions 52
• Majestic
• Imperial Fresh
• Kroger
• Utah Onions
• Food Lion

As a result of the variety of brand names, it may be difficult to identify which onions are impacted by the recall. The FDA recommends disposing of onions if you cannot identify if they were shipped from Thomson International.

"If you do not know where your onions came from follow the advice 'when in doubt, throw them out,'" food safety lawyer Bill Marler told Business Insider.