Calf’s liver should be pale and pinkish in color; beef liver is darker and has a stronger taste and odor. Pork liver has the strongest flavor; chicken liver has the mildest. Liver should have a bright color with a moist but not slimy surface and a fresh smell. Beef, pork, lamb, and poultry hearts tend to be tough; younger hearts are more tender. Hearts should have a fresh smell and red color—not brown or gray. Veal or lamb kidneys should be firm, pink or pale red rather than purple, and should not have a uric acid smell. Calves liver should be a deep rose color, not red or purple. Look for kidneys that are evenly colored and do not have dry or dull spots. Beef, pork, and lamb brains should be firm, plump, and pinkish-white. Veal, beef, lamb, and pork sweetbreads should be plump, firm, and white. Tripe should be pale white.