The present invention provides a method for producing a less-painful immunogenic composition of a hydrophobic protein in a pharmaceutically acceptable carrier suitable for administering to a mammal, comprising the steps of (a) solubilizing said hydrophobic protein with a zwitterionic detergent to make a first composition; (b) altering said first composition, such that the altered composition produces a reduction in pain as measured in the rat footpad model as compared to said first composition.