A method for improving the half-life of milk comprising the step of: a) contacting milk with an antibody raised against at least one of the following: i) a molecule required for survival by at least a micro-organism that is responsible for reducing the half-life of milk; ii) a molecule required for growth by at least a micro-organism that is responsible for reducing the half-life of milk; iii) a molecule required for survival by at least a micro-organism that aids other micro-organisms to reduce the half-life of milk; iv) a molecule required for growth by at least a micro-organism that aids other micro-organisms to reduce the half-life of milk.