An update on our warning about products containing peanut butter: Five hundred people have now become ill after eating products containing peanut butter contaminated with salmonella–including more than 100 children under the age of five. And, it now turns out, the plant that produced the peanut butter knew it had a salmonella problem and went on selling the contaminated products anyway.

Don’t eat another peanut butter cookie, cake, or anything else that has peanut butter as an ingredient. That’s the advice of federal health officials, who are investigating a nationwide outbreak of salmonella that has so far sickened 470, hospitalized at least 90, and killed as many as six people.