Physical and chemical treatments have been investigated for the treatment to remove biofilms. This thesis examines the problem of the removal and prevention of biofilms by: (i) using a water jet to determine biofilm stability and (ii) testing the effect of β-phenylethylamine (PEA) on growth and biofilm amounts. Three dimensional structures of biofilms vary in different genetic backgrounds of E. coli, we wanted to see whether changes in structures were paralleled by differences in stability of the biofilm. The water jet apparatus was used to test biofilm stability of E. coli mutants. Alteration of the cell surface structures was detrimental to biofilm stability, while alterations in metabolism had less effect on stability. PEA (0 to 50 mg/mL) was applied to bacterial strains to see the effects on growth and biofilm amounts. PEA had an inhibitory effect on growth and biofilm amounts of some bacterial strains tested.