Effect of heat treatment of bovine colostrum on bacterial counts, viscosity, and Immunoglobulin G concentration.
A study was conducted to identify the optimal temperature and time at which heat treatment of bovine colostrum would least change viscosity and IgG concentrations yet reduce bacterial count. First-milking colostrum with >50g of immunoglobulins/L (measured by colostrometer) was collected from 30 Holstein cows. Aliquots of colostrum were heated for 0, 30, 60, or 90min at 57, 60, or 63 degrees C in a water bath. Samples were examined for viscosity, IgG(1), and IgG(2) concentrations, standard plate count, coagulase-negative staphylococci, environmental streptococci, coliform, gram-negative noncoliform, Streptococcus agalactiae, and Staphylococcus aureus counts. All heat treatments reduced counts of all bacteria groups measured compared with untreated colostrum samples. Heat treatment at >or=60 degrees C denatured IgG(1) compared with untreated colostrum; however, colostral IgG(2) levels were not reduced when temperature was held at 60 degrees C for <60min. Viscosity was not affected when temperature was held at 60 degrees C for <60min. In this study, heat treatment of bovine colostrum at 60 degrees C for 30 or 60min reduced bacterial count, slightly reduced IgG concentration, and did not affect viscosity.
Elizondo-Salazar
J A
JA
Department of Dairy and Animal Science, The Pennsylvania State University, University Park 16802, USA.
Jayarao
B M
BM
Heinrichs
A J
AJ
D000818:Animals; D018407:Bacterial Physiological Phenomena; D002417:Cattle; D003126:Colostrum / Q000737:chemistry* / Q000382:microbiology*; D003612:Dairying / Q000379:methods*; D005260:Female; D005511:Food Handling / Q000379:methods*; D006358:Hot Temperature; D007074:Immunoglobulin G / Q000032:analysis*; D014783:Viscosity
D007074:Immunoglobulin G