A combination of microfiltration and high pressure treatment for the elimination of bacteria in bovine colostrum

Bovine colostrum is a unique source for biomolecules and a valuable raw material for the production of nutraceuticals. The highly variable microbial quality of raw colostrum and its thermo-sensitive nature complicate the manufacture of safe and stable colostrum products for human use. A novel combined process comprising microfiltration (MF) and subsequent high pressure processing (HPP) was investigated. Skimmed colostrum contaminated with various bacteria species was subjected to cross-flow MF at pore sizes of 1.4 and 0.8 μm. The MF permeates contained a residual microbial burden that was reduced to undetectable levels by HPP at 400 and 500 MPa for 10 min. Native IgG was reduced to 36–73% (MF + 400 MPa HPP) and 19–30% (MF + 500 MPa HPP) of the original content. In direct application to contaminated colostrum, HPP was shown to be less detrimental to IgG than heat treatment at conditions giving similar microbial reduction efficacy.