Traditionally, the key policy issues for the agricultural and food sector have focused on prices and quantities. For example, one of the major stated purposes of the 1990 farm bill is "to ensure consumers an abundance of food and fiber at reasonable prices." Now, however, assuring the quality of the food supply is taking on greater importance. Quality assurance encompasses the management (and often reduction) of foodborne human health risks arising from multiple sources: microbiological pathogens (e.g., E. coli), nutritional risks (e.g., too much fat in the diet), pesticide and animal drug residues, and naturally occurring and environmental toxicants. Quality assurance is set also in the context that consumption of some foods may help in disease prevention. Consumers' increased awareness of relationships between food safety, diet, and personal health have led them to make quality characteristics more central to their food choices. Producers and processors have a stake in providing safer and higher quality products in order to attract these consumers, to protect themselves from possible liability attached to inferior quality products, and to comply with government regulations. Meanwhile, introduction of new production and processing technologies as well as increases in international trade are altering the mix of foods whose quality must be assured.