I reckon that there are cases of infection with Listeria in the processing of wool, feathers, lint, hair and other raw materials, animals and birds. http://skywritingservice.com/blog/listeria-important-facts-you-might-dont-know Listeria can get into the human body due to the ingestion of unwashed vegetables and drink water. There are well known cases of human infection with Listeria via the micro-trauma of the skin. It's awful!