Beef retailers use a wide variety of packaging to merchandize fresh beef. A general category of packages known as case-ready has increased in numbers over that last few years.
Case-ready simply describes a package sent from the beef processing facility that requires no repackaging in the store before being placed in the meat case. Case-ready packages contain a USDA inspection insignia on the package, which includes the exclusive USDA establishment number assigned to the processor that packaged the beef.
First types of case-ready packaging are available : Modified-atmosphere lidding film package
Modified Atmosphere Barrier Packaging - Modified atmosphere packages house beef products in an environment other than air. Modified atmosphere packages typically are described as rigid plastic trays, which hold the beef product and an absorbent pad, sealed with a clear high-barrier plastic film. During the manufacturing of these packages, a machine will vacuum residual air from the tray and then flush the tray with a modified atmosphere immediately prior to sealing the package with the clear film. The modified atmospheres typically contain purified gases found in air (oxygen, carbon dioxide, nitrogen and/or carbon monoxide) and each gas has a distinct use or purpose. Nitrogen has no effect on meat color or bacteria growth, but is used as a dilutant allowing other gases to be used in proper ratio. Oxygen is used because it causes the bright red color consumers prefer. Carbon dioxide is used to decrease or prohibit the growth of spoilage bacteria. Carbon monoxide was approved for use in 2002 by the FDA and USDA at a level of 0.4% and works with myoglobin to form a strong bond that creates a red color. Carbon monoxide is approved for use in a gas mixture that does not include oxygen and the result is a decrease in oxidation, which creates a stabilizing effect and increases case-life. The most common modified atmospheres consist of 80% oxygen / 20% carbon dioxide or 0.4% carbon monoxide / 30% carbon dioxide / 69.6% nitrogen.