Color and oxidative rancidity were determined for chilled (3 ‫ע‬ 2ЊC) and frozen (Ϫ17 ‫ע‬ 3ЊC) boneless pork chops packaged in vacuum or air and irradiated to an absorbed dose of 0, 1.5 or 2.5 kGy (chilled) or 0, 2.5 or 3.85 kGy (frozen) of electron beam or cobalt 60 irradiation. Irradiation of vacuum-packaged chops produced redder, more stable (color and rancidity) product. More pronounced oxidative rancidity and less stable display color were noted for samples irradiated in aerobic packaging. Irradiation source had varying but limited effects on color and rancidity. Optimum packaging conditions can control color and rancidity changes in boneless chops, thereby enabling irradiation to be a useful intervention technology.

The effects of two doses (2.0 and 3.5 kGy) of nonradioactive irradiation on color and oxidative properties were determined and compared to nonirradiated controls for frozen, raw and precooked, ground beef patties with 10 and 22% fat packaged in vacuum and aerobically. Irradiated raw patties were initially darker and less red than controls, but color of control and irradiated samples became more similar during display. Irradiation increased external redness in precooked patties that were vacuum‐packaged. Aerobic packaging, in combination with irradiation, increased lipid oxidation and discoloration, whereas vacuum‐packaged patties displayed for up to 21 days had minimal changes in color and lipid oxidation. Irradiation versus the controls significantly reduced bacterial counts.

The effects of two doses (2.0 and 3.5 kGy) of nonradioactive irradiation on flavor, texture and aroma were compared to nonirradiated controls for (1)frozen raw and precooked, ground beef patties with 10 and 22% fat packaged in vacuum or aerobically: (2) frozen, vacuum-packaged, boneless beef steaks; and(3) chilled, vacuum-packaged, boneless, beef steaks that were repackaged in an oxygen-permeable film (PVC) after 14 days of storage. Samples were evaluated by a highly trained descriptive panel for fifteen sensory attributes for ground beef patties and eighteen sensory attributes for whole muscle beef. Irradiation had minimal effects on flavor, texture, and aroma offrozen, raw andprecooked, ground beef patties: frozen boneless beef steaks; and vacuum-packaged, chilled, boneless, beef steaks. Reintroduction of oxygen to irradiated beef by repackaging into PVCfilm after vacuum aging increased liver-like (at 3.5 kGy) and toughness (at 2.0 kGy) attributes and slightly decreased beef identity and browned/roasted flavor notes (at 2.0 kGy.) ' Contribution No. 97-31-J from the Kansas Agricultural Experiment Station. Send correspondence to

Flavor, texture, and aroma were determined for chilled (3 ‫ע‬ 2ЊC) and frozen (Ϫ17 ‫ע‬ 3ЊC) boneless pork chops packaged in vacuum or air and exposed to an absorbed dose of 0, 1.5, or 2.5 kGy (chilled) or 0, 2.5, or 3.85 kGy (frozen) of electron beam and cobalt 60 irradiation. Irradiation (≤3.85 kGy) had minimal effects on aroma, flavor, and textural attributes in chilled and frozen boneless pork chops. Irradiation source had limited effects and packaging type had the greatest influence. Consumers reported no difference (PϾ0.05) between irradiated (2.5 kGy cobalt 60 irradiated, chilled, vacuum-packaged, boneless, pork chops) and control samples for overall acceptance, meatiness, freshness, tenderness and juiciness.

The effects of two doses (2.0 and 3.5 kG'y) of nonradioactive irradiation on color and oxidative properties were determined and compared to nonirradiated controls for frozen and chilled vacuum‐packaged boneless beef steaks. The chilled steaks were repackaged in oxygen‐permeable film 14 days after irradiation. Irradiation up to 3.5 kGy had minimal effects on color and oxidative rancidity and significantly reduced bacterial counts of frozen and chilled, vacuum‐packaged, beef steaks stored and/or displayed for up to 28 days. Irradiated steaks that were rewrapped in permeable film were microbially acceptable at 5 days of display and had more color stabiliry than the controls. Although no differences in TBA numbers between dose levels were observed for chilled steaks rewrapped in permeable film, these steaks had a TBA number of 2.1 after 5 days of retail display compared to 0.2 for vacuum‐packaged steaks displayed for 14 days.