Growth medium, type of inert surface and storage temperature are important determinants of biofilm formation (Hood and Zottola,1995). In the present study, in an effort to simulate soiling substrates encountered in beef fabrication, fat-lean homogenate (liquid residue) and ground beef (solid residue) were utilized to evaluate adherence/attachment and subsequent biofilm formation of a six-strain composite of E. coli O157:H7 to stainless steel and HPDE