the viability of c. jejuni biofilms growing in different conditions was investigated by conventional plate counts and microscopy after nucleic acid staining. differences were detected for each condition tested. however, total biofilm cells grown at 42°c microaerobically and at 22°c aerobically were not significantly different, which might indicate that c. jejuni biofilms grown in the natural environment might contribute to food contamination. further, it was demonstrated that viable but not culturable (vbnc) cells might exist in c. jejuni biofilms, since both biofilm and planktonic cells in the 22°c aerobic condition had great differences in their cell counts obtained by plate counting and microscopy. protein profiles of c. jejuni biofilms grown in different conditions were also determined and different protein patterns were observed by 1d sds-page. therefore, we concluded that c. jejuni underwent physiological changes when growing in its biofilm mode.