EPIFLUORESCENCE IMAGE-ANALYSIS AND CULTIVATION OF FOODBORNE BIOFILM BACTERIA GROWN ON STAINLESS-STEEL SURFACES

In this study, biofilm was grown on stainless steel surfaces (AISI 304 ) for 2, 5, and 10 d at 25-degrees-C in slime broth inoculated with th e food spoilage microbes Bacillus subtilis, Listeria monocytogenes, Pe diococcus pentosaceus, and Pseudomonas fragi. The biofilm developing o n steel surfaces were investigated using conventional plating, quantit ative glycocalyx determination, and epifluorescence microscopy with im age analysis. The results showed that B. subtilis and P. fragi could e asily be cultivated after 2 d growth. After a growth period of 10 d, t he cells were difficult to cultivate from the surface, and the growth was detected better by microscopy. L. monocytogenes, on the other hand , could easily be detected by cultivation after 2, 5, and 10 d. The gr eatest amount of slime was produced by P. pentosaceus, as was also sho wn by epifluorescence microscopy.