Author : Engel, Karl Heinz

Summary : Safety assessment is based on the idea to determine whether an introduced protein is "as safe as" proteins already present in foods. This includes data on: 1) the history of the donor organism used as source for the gene; 2) the expression level of the newly introduced protein in the host plant; 3) the resulting dietary human exposure. A major focus will be on the comparison of the biochemical, physicochemical and immunological properties of the newly introduced proteins to known protein toxins, antinutrients or allergens. The following criteria have to be assessed: 1) structural and functional properties/mode of action; 2) amino acid homology to known mammalian protein toxins; 3) stability under simulated mammalian digestion conditions; 4) toxicity studies. In most cases, the amounts of the newly expressed proteins in the GM plants are so low that their isolation in amounts sufficient for subsequent tests is not feasible. If GM microorganisms are used to produce the protein in higher amounts special care has to be taken in order to establish the chemical and functional equivalence of bacterial and plant protein. The newly introduced proteins in GM plants presently in commerce are degraded under simulated mammalian digestion conditions as rapidly as common plant proteins. Acute oral gavage sudies as well as short tem (28 days) feeding studies did not show any adverse effects.