DETECTION OF RECOMBINANT CHYMOSINS IN CALF RENNET BY ENZYME-LINKED-IMMUNOSORBENT-ASSAY

The presence and the origin of recombinant chymosin can be detected in milk-clotting enzyme solutions by antigen coat plate-enzyme-linked im munosorbent assay (ACP-ELISA) or sandwich ELISA. The method is based o n the detection of contaminant proteins derived from microorganisms or from the culture medium, which are always present in fermentation-pro duced chymosin solutions. The specific polyclonal antibodies obtained from the sera cf rabbit and hen permitted identification of the contam inant proteins in the commercial solutions. A simple dilution of the s ample is sufficient to detect the addition of 0.5% Chymogen (Hansen) o r Maxiren (Gist-Brocades) and 2.5% Chymax (Pfizer) in calf rennet.