Method for extending shelf-life and prevention of discoloration of meat

Abstract

The current invention covers an improved meat-packaging procedure and machine for packaging meat cuts for long-term storage at temperatures of between 28° and 32° F. The process includes sealing meat cuts within a master bag containing oxygen scavenger materials capable of reducing the residual oxygen content of the atmosphere within the bag to 0 ppm within 24 hours of sealing. Gas is injected into the master bag to form a nitrogen-rich storage environment of at least 50% nitrogen. A small amount of carbon monoxide gas (0.1% to 5%) is preferred for the storage environment, as this helps to preserve the red coloration of meat under long-term storage conditions. The over-wrap of the meat trays can be perforated so that gas exchange occurs within the master bag between the interior and exterior of the meat tray to absorb the residual oxygen inside the meat trays. For meat trays containing meat with poor color stability, oxygen scavengers are preferably placed within the meat trays. For cuts with good color stability, the oxygen scavengers may be placed outside the meat trays. Meat can be stored by this system for up to 15 weeks and up to nine days of retail display life.

Description

BACKGROUND OF THE INVENTION [0001] Meat production and packaging is well known in the industry. Traditionally, once a primal cut of meat has been made, it is placed in a package containing ambient air and the lidding material is fed from a roll and over the tray covering the meat cut. The tray edges are typically sealed to form the finished product. However, since the air allows the meat to become discolored due to the onset of metmyoglobin, the meat normally undergoes vacuum skin packaging in order to maintain freshness and reduce spoilage of the meat cut. [0002] The conventional vacuum packaging process normally does not allow the meat cut to exhibit a deep red pigment desired by retailers and consumers. Subsequently, once these vacuum-packed meat cuts reach the supermarkets or meat distribution centers, the primal cuts are cut into smaller cuts. These smaller cuts are then repackaged or displayed in a case for sale. In a very short time, the meat cuts lose the desired red color a...

AI Technical Summary

Benefits of technology

[0029] Another advantage of the present invention is that a retailer is capable of unpackaging a days' supply of fresh meat cuts at a time. The master package is protected from oxygen exposure until the seal is released and the individual packages are placed in the retail case. In essence, the shelf life clock does not begin ticking until the fresh meat is placed in the retail case. For central packaging operations, by utilizing the master packages, the shrinking of meat cuts due to handling, transportation and temperature fluctuations is greatly reduced to virtually zero shrinkage.

[0030] The main advantage of the invention is the zero-oxygen system gas environment in the master bag stops the formation of metmyoglobin, the agent that causes fresh meat to become discolored. By stopping metmyoglobins formation, the metmyoglobin reducing activity (MRA) of the meat muscle is retained. Because the oxygen concentration in the master bag is zero ppm, metmyoglobin cannot form and the discoloration process never occurs. Further, under the zero-oxygen system, only lactic acid and other slow growing anaerobic bacteria will grow; and the growth of faster growing aerobic bacteria causing rapid spoilage is restricted.

[0031] Shelf-life in the retail case is increased by one to seven additional days, depending upon the type of meat cut. The present packaging system preserves the enzymatic activities of meat-muscle that maintains the bright cherry red color of each meat cut, the retail display life of the meat is extended dramatically. The addition of carbon monoxide as part of the gas mixture environment also helps preserve the reddish color of the meat as a layer of carbon monoxymyoglobin is formed on the meat surface,

[0032] The apparatus used in the invention will automatically package meat trays into a single master bag containing oxygen scavengers with appropriate oxygen absorption capacity to reduce the half-life of oxygen inside the master bags and meat packages to between 0.6 and 2.0 hours. The master bags are formed around the meat trays and the ambient air is flushed from the bag. The bag is then injected with the desired gas mixture environment that is preferably 100% nitrogen or nitrogen rich (>50%) with the balance a mixture of other gases, preferably carbon monoxide and carbon dioxide. Some small quantity of carbon monoxide (≧0.1%) is preferred. The master bags can then be stored for several weeks at freezing or below freezing temperatures (28°-32° F.) until needed for placing into a retail display for several days before meat discoloration occurs.

Problems solved by technology

This achieves extremely long shelf-life for storage of retail-ready meat cuts.

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