A compound containing one mole of a free fatty acid and one mole of the ammonium salt of the fatty acid and represented by the structural formula (I):CH3(CH2)xCOOH.CH3(CH2)xCOO−;NH4+ ; ;(I)wherein x is 6, 7 or 8. Bacterial contaminated surfaces may be disinfected or bacteria removed from a bacterial contaminated surface by applying onto the surface a bactericidally effective amount of the compound.