The influence of Morganella morganii isolated from cheese on the formation of biogenic amines was studied in raclette-type cheeses. Three variants were produced. One variant containing a cadaverine- and histamine-forming strain, one variant with a putrescine- and histamine-forming strain, and a variant without M. morganii. After 130 d of ripening, live M. morganii was found in the outer layers but no longer inside the cheese. The cheeses with the cadaverine-forming strain exhibited a decreasing cadaverine gradient from the outside (on average 310 mg kg-1) to the inside (160 mg kg-1). Putrescine was present in the cheeses with the putrescine-forming strain. Its concentration averaged 59 mg kg-1 in all layers. All cheeses with M. morganii contained also histamine with concentration less than 50 mg kg-1. The results reveal new information on the survival of M. morganii as well as its ability to form biogenic amines in cheese.
