Lettuce growers and salad chains are embarking on a consumer education push to share that their products are safe amid a cyclospora outbreak that has sickened thousands of people across the U.S.Gotham Greens, which was founded in New York, recently took to social media to say that its products are grown in controlled greenhouses and therefore not affected by the outbreak. Meanwhile, Little Leaf Farms, which is based in Massachusetts and also uses controlled greenhouses, has published several Instagram videos with its CEO, explaining why its lettuce is OK to eat. And fast-casual chain Sweetgreen published an open letter from its founders, saying, “Our food has not been identified in connection with the current cyclospora outbreak.”

Companies hope this messaging will reassure consumers wondering what they can and cannot eat as news of the parasite dominates headlines. The U.S. has received reports of more than 4,173 laboratory-confirmed cases of cyclosporiasis (the illness caused by the parasite cyclospora) since May 1. Some of these cases have been linked to iceberg lettuce in nine states, per the CDC, although there has been mixed messaging from health officials on whether the supplier Taylor Farms is responsible.