The demand curve D₁ shifts with a change in any nonprice factor that affects demand. If tomatoes are suspected to be a source of salmonella, consumers will demand fewer tomatoes at any given price and the demand for tomatoes will shift inward, from D₁ to D₂. In contrast, if tomatoes are found to have cancer-fighting properties, the demand for tomatoes will shift outward, from D₁ to D₃.