Method for producing milk with a lowered bacterial content

A method for treating raw milk to produce treated milk having a lower bacterial content than the raw milk, in which raw milk is first divided by centrifugal separation into a fraction consisting of cream and a fraction consisting of skim milk, comprising the further steps of:

• (a) subjecting the skim milk fraction to microfiltration by passing the skim milk fraction through a microfilter having a retaining membrane surface, the pores in said microfilter having an average diameter of at least about 0.8.mu. and less than about 2.0.mu., to yield a permeate which consists of skim milk with a lower fat globular, protein and bacterial content than the skim milk fraction, in which the microfiltration is carried out by directing the skim milk through a circulation path comprising the microfilter, at which the skim milk is directed to flow in a cross-flow filtration path, which is generally parallel with the retaining membrane surface during the microfiltration, (b) separating from the retaining membrane surface a retentate which consists of skim milk with a higher fat globular, protein and bacterial content than the skim milk fraction, (c) sterilizing the retentate, and (d) separately recovering the retentate, permeate and cream fractions.