When you're vegan, food poisoning slips down your list of concerns. Take care to wash your produce and you should be OK—right? That was the mindset of Anne Sullivan (not her real name). Then she poisoned herself. Sullivan was understandably proud of her vegan diet meals and she loved the way healthy eating made her feel. She knew that she needed to up her protein, so when she found a white bean stew recipe online, Sullivan knew she had to try it. After pre-soaking her beans like the recipe directed, she put them in her slow cooker. "I started them in the morning and left them simmering all day—I thought that was enough," she said. Several hours later, Sullivan lifted the lid: "The beans weren't any larger than before. I thought it was weird they were the same size." She took a bowl with her to her job at the library, which she ate for lunch; she couldn't believe it—the beans were tough and chewy, clearly not done. She was still at work when she began to feel dizzy and faint. "I must have looked awful, too, because my boss told me to go home and get some sleep. I felt like throwing up." She headed for the library couches and took a short nap. "I woke up feeling a bit better, and afterward I went and ate a large meal, which seemed to help with the symptoms." The following day—still unaware of what made her sick—Sullivan served up the stew for herself and her boyfriend. "We had taken a few bites as I was telling him I didn't know what made me sick the day before. All of a sudden he said, What if it's these beans? He looked it up online: Sure enough, we were poisoning ourselves all over again." Don't be caught off-guard: Know the 7 signs of food poisoning before it hits. Sullivan and her boyfriend went out for lunch instead, but before they even got to the restaurant, they both had symptoms. The issue? Uncooked beans contain a naturally occurring toxin called phytohaemagglutinin; cooking reduces levels of the toxin to tolerable levels. But when beans are undercooked, the toxin can be up to five times as potent, causing gastroenteritis, and symptoms like nausea, dizziness, and diarrhea. The critical mistake that Sullivan made was failing to boil the beans for at least ten minutes, according to food experts at Ohio State University. After pre-soaking the beans for at least five hours, drain, rinse, and then boil them. Putting them in a slow cooker without boiling them can actually increase the level of toxins. "I had no idea—I think most people assume beans will cook in a slow cooker. Most recipes seem to assume you're using canned beans, which are fully cooked." As for your slow cooker, don't worry—it won't give you food poisoning. Just make sure to cook your food thoroughly. which is one of the most common slow cooker mistakes people make. "I'm very careful now, I pre-soak and then boil the beans," she says. "If I do add them to my slow cooker, I make sure they're fully cooked first." Knowing that uncooked beans can be toxic is important, but you should also know which food is the number one cause of food poisoning.