HIGH PRESSURE PROCESSING OF BOVINE COLOSTRUM: IMPACT ON QUALITY, PATHOGENS, AND TRANSFER OF PASSIVE IMMUNITY

摘要

The objectives of this study were to 1) measure the effects of high pressure processing (HPP) on microbial load, viscosity, and immunoglobulin concentration when applied to bovine colostrum as an alternative to thermal pasteurization and 2) determinethe impact of HPP on the transfer of passive immunity to calves.First milking colostrum from 6 Holstein-Friesian cows were inoculated with known concentration of microorganisms and pressure processed at 300 MPa for up to 60 minutes and at 400 MPa for up to 30 minutes. The extent of inactivation of native bacteria, Escherichia coli, Salmonella enterica subsp. enterica serovar Dublin, Mycobacterium avium subsp. paratuberculosis (MAP), bovine herpesvirus type 1, and feline calicivirus (as model for non-enveloped viruses) were determined after processing. Colostrum immunoglobulin G (IgG) content was measured before and after pressure processing. Shear stress and viscosity for each treatment was determined over shear rates encompassing those found during calf feeding and at normal bovine body temperature (38.6°C). Colostrum was then collected from 15 cows and processed at 400MPa for 15 min. Serum IgG concentration was measured and apparent efficiency of absorption was calculated in 15 calves fed 3.8 L of pressure processed colostrum and compared to 15 calves fed heattreated colostrum.