Northeast Iowa health officials now know why several hundred people got sick after eating free Thanksgiving Day dinners in Black Hawk County. Health officials are blaming the illness outbreak on bad turkey served at two separate meal sites in the Cedar Valley. Nearly 400 people who ate holiday dinners at Cedar Heights Presbyterian Church in Cedar Falls and Ryder Integrated Logistics in Waterloo got sick after eating the free meals. Black Hawk County environmental health manager Mark Linda says preliminary tests from a sample of turkey served at both meal sites showed positive signs of two different forms of bacteria, with levels high enough to cause illness. Both meals were catered by a local Hy-Vee food store, which cooperated fully in the investigation. Linda says bacteria was found in one sample of a home-delivered meal, but could have been introduced to the food after it was delivered by Hy-Vee. Inspectors made several visits to the store after the illnesses were reported, but their findings haven’t yet been made public.