If you have diarrhea, fever or stomach cramps, and you recently polished off a chicken salad sandwich, the onions you added might be to blame. Red onions distributed by Thomson International Inc.’s facility in Bakersfield, California, were recalled on August 1 due to possible salmonella contamination. The company also voluntarily recalled yellow, white, and sweet yellow onions shipped from the facility since May 1, for fear of cross contamination.

The infected onions carry salmonella, a bacteria that causes food poisoning. The Centers for Disease Control and Prevention report that there are 869 cases and 116 hospitalizations to date covering 47 states. No one has died. Salmonella is particularly risky for young children or adults over 65. If you have eaten contaminated food, symptoms can appear anywhere from 12 to 72 hours after consumption, and include cramps and diarrhea. The diarrhea can be dangerously dehydrating for some people.

According to Greg Yielding, executive vice president of the National Onion Association, this is, to the best of his knowledge, the first foodborne illness from onions. He explained that onions haven’t been a source of any foodborne illness before, certainly not salmonella. “ They have a skin on them that protects them,” he said in an interview with Medical Daily. “And we never really had this before.” Yielding is holding out for answers. “We’re still waiting for the FDA, for their investigation, to see what caused this, I would suspect cross contamination with something else.”

“[I]f you can’t tell where your onions are from, don’t eat them,” the CDC recommends. “Throw them away.” Onions from Thomson International Inc. were also sold as Thomson Premium, TLC Thomson International, Tender Loving Care, El Competitor, Hartley’s Best, Onions 52, Majestic, Imperial Fresh, Kroger, Utah Onions and Food Lion. If you think you have had contaminated onions in your home or place of business, the CDC also recommends that you wash and sanitize any surfaces that may have come in contact with onions or their packaging. This includes countertops, storage bins, refrigerator drawers, knives and cutting boards.

The CDC lists 8 stores that stocked the potentially contaminated onions. It also lists prepared foods that may contain the onions, including salsa, cheese dips, pizzas, and some pre-prepared food like macaroni salads and chicken salads.

According to the CDC this is the first salmonella outbreak of 2020.

Yielding also explained that other onion growers are being especially diligent, double checking their stock to ensure that onions not from Thomson International Inc. are safe to eat. Onions that have been thoroughly cooked are safe to eat.