Beef semitendinosus (ST) muscles with injected water (3 or 10% of raw muscle weight) and
phosphate (0.3%) were cooked to final internal temperatures of 130 (held at 130 for 121 min),
140 (held at 140 for 12 min), 145, or 155°1\ then sliced at 30, 45, 120, 130, or 145<>P by either
a dull or a sharp slicer. Biceps femoris (BF) muscles had the same treatment but only at 3%
water addition. Controls were uninjected muscles from the opposite side of the carcass. For
ST muscles (all with 0.3% added phosphate), 3% added water resulted in less iridescence than
controls and those containing 10% added water. Iridescence was also lowered by cooking to
130°F (held for 121 min), slicing at 30 ̊F or slicing with a dull slicer blade. Iridescence varied
(P<.05) among muscles from different carcasses under the same cooking and slicing conditions.
BF muscles had much less iridescence than ST muscles. Our results show that processing-cooking-
slicing alterations can help reduce iridescence, especially for the ST (eye of round)
muscle.
