regarding animal wellbeing). Direct effects of any abnormalities in patterns of gene expression on food safety are unknown. However, because stress from these developmental problems might result in shedding of pathogens in fecal material, resulting in a higher load of undesirable microbes on the carcass, the food safety of products, such as veal, from young somatic cell cloned animals, might indirectly present a food safety concern. As a somatic cell clone develops and nuclear reprogramming is completed, patterns of gene expression would approach those of a non-engineered individual. Indeed, the health and wellbeing of somatic cell clones approximated those of normal individuals as they advance into the juvenile stage. For example, somatic cell cloned cattle reportedly were physiologically, immunologically, and behaviorally normal, and exhibited puberty at the expected age, with high rates of conception upon artificial insemination (Lanza et al., 2001). Two of these individuals have given birth to calves that seem phenotypically normal. There are to date no published comparative analytical data assessing the composition of meat and milk products of somatic cell clones, their offspring, and conventionally bred individuals (although several studies are in progress; Bishop, personal communication, 2002). However, the committee found it difficult to characterize the level of concern without further supporting evidence regarding food product composition. Currently, there is no evidence that food products derived from adult somatic cell clones or their progeny pose a hazard (i.e., there is no evidence that they present a food safety concern).
A number of types of genetically engineered animals will be developed primarily for food, and others will be developed primarily for producing non-food materials such as pharmaceuticals, vaccines, fibers, and other high value products. The principles for assessing the safety of food from genetically engineered animals are qualitatively the same as for non-engineered animals, but animals genetically engineered for non-food products might present additional concerns relating to the nature of the products that they generate. As for all foods or food products, those from genetically engineered animals should be evaluated for agents—chemical or biologic—which affect the safety of the food for the human consumer.
Animals used for xenotransplantation are not considered safe for human consumption and are excluded from the food chain by current regulations (see Chapter 7 for information on food animal regulations). Their exclusion is based primarily on concerns about persistent tissue residues of agents used to anaesthetize the animal prior to harvesting the tissues and organs. If there were any possibility that such animals might be rendered and considered for further processing into useful human food or medical products, concerns about