STABILITY OF MEMBRANE-STERILIZED BOVINE IMMUNOGLOBULINS ASEPTICALLY ADDED TO UHT MILK

Lyophilized immunoglobulin (IgG) of 56% purity isolated from Cheddar c heese whey was reconstituted with distilled water to a protein content of 60-70 mg/mL. The solution was membrane-sterilized (0.2 mu m) and a septically injected into cartons of UHT milk. This method could be use d for fortification of UHT products without denaturing IgG. Concentrat ion of IgG remained constant in milk stored at 4, 25 and 35 degrees C over 5 mo. However, when stored at 25 and 35 degrees C, the milk thinn ed probably due to residual enzymes in the IgG solution. D values meas ured between 62 and 80 degrees C for thermal destruction of IgG in UHT milk appeared to confirm shelf life results.