Palmerston North, New Zealand
Palmerston North, New Zealand

Time filter

Source Type

Abernethy G.,Fonterra | Otter D.,Agresearch Ltd. | Otter D.,Previously Fonterra Co operative Group Ltd
Journal of AOAC International | Year: 2010

An AOAC collaborative study was conducted to evaluate an affinity LC procedure for measuring immunoglobulin G (IgG) in selected dairy powders. The powders were extracted with 0.15 M sodium chloride solution and the pH was adjusted to 4.6 to precipitate caseins, which would otherwise lead to an overestimation of IgG. The analyte was then bound to a commercially available Protein G affinity cartridge and selectively eluted with a glycine buffer at pH 2.5. Detection was at 280 nm and quantification was made against a calibration curve prepared from bovine serum IgG. The samples analyzed included the likely matrixes for which this assay will find commercial use, namely, high- and low-protein-content colostrum powders, tablets containing colostrum powder, and some IgG-containing dairy powders; milk protein isolate, whey protein concentrate, and skim milk powder. Eleven laboratories provided data for the study and assayed blind duplicates of six materials. The repeatability RSD values ranged from 2.1 to 4.2% and the reproducibility RSD values ranged from 6.4 to 18.5%. The Protein G method with casein removal has adequate reproducibility for measuring IgG in colostrum-derived powders that are traded on the basis of IgG content as a colostral marker.

Loading Previously Fonterra Co operative Group Ltd collaborators
Loading Previously Fonterra Co operative Group Ltd collaborators