Temporal equivalence between test species and humans: General toxicity issues

The question of whether temporal equivalence can be established between tes t species and humans and be useful in the safety assessment of food additiv es has puzzled risk assessors throughout decades. The basic biological elem ents in any mammalian species, including humans, such as homeostasis, basal metabolism and body size/surface area, reproduction features, the timing o f cellular proliferation, and, aging and health as well as the relation bet ween aging and the diet are essential in this discussion. It is concluded t hat exposure studies covering selected segments of the total lifetime of an y animal species cannot replace lifetime studies in the same animal species in the routine safety testing of food additives, but they may in many case s turn out to become the pivotal study for the entire safety assessment.