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.

1 . A packaging system for minimizing meat discoloration comprising: 
 a retail meat tray comprised of a tray with one or more oxygen scavenger sachets and an absorbent pad over-wrapped with a gas permeable plastic-based film permitting atmosphere exchange between the interior and exterior of the meat tray, said oxygen scavenger sachets containing an iron-based oxygen absorbing material self-activated in an atmosphere of greater than 70% relative humidity;    a sealed master bag containing at least one retail meat tray, said master bag flushed prior to sealing to remove oxygenated air from the interior of the bag to obtain an initial atmosphere equal to or less than 5% oxygen and injected with an oxygen-free, inert gas comprised of greater than 50% inert gas; and    an oxygen absorption capacity of the oxygen scavenger sachets sufficient to achieve a half-life for the 5% residual oxygen of equal to or less than 2.0 hours and reach a zero oxygen storage atmosphere within 24 hours of sealing said master bag.    
     
     
         2 . The packaging system for minimizing meat discoloration of  claim 1 , wherein the oxygen scavenger sachets comprise: 
 a porous bag with an active surface area of between 4 to 64 square inches and porosity levels ranging from 20 to 120 gurly per second;    chemical granules ranging from 0.001 mm to 1.5 mm in diameter; and    a total weight of absorbing chemical of between 1 gram to 300 grams.    
     
     
         3 . The packaging system for minimizing meat discoloration of  claim 2 , wherein the chemical granules comprise: 
 less than 25% iron;    less than 35% carbon;    less than 20% vermiculite;    less than 10% de-ionized water; and    less than 10% NaCl salt.    
     
     
         4 . The packaging system for minimizing meat discoloration of  claim 3 , wherein the chemical granules comprise less than 10% zeolites.  
     
     
         5 . The packaging system for minimizing meat discoloration of  claim 1 , wherein all the oxygen scavenger sachets sealed within the master bag obtain an absorption capacity of at least 10 mL per pound of meat.  
     
     
         6 . The packaging system for minimizing meat discoloration of  claim 1 , wherein the injected gas comprises nitrogen as the inert gas.  
     
     
         7 . The packaging system for minimizing meat discoloration of  claim 1 , wherein the injected gas comprises less than 5% carbon monoxide.  
     
     
         8 . The packaging system for minimizing meat discoloration of  claim 1 , wherein the injected gas comprises: 
 greater than 50% inert gas;    less than 5% carbon monoxide; and    carbon dioxide.    
     
     
         9 . The packaging system for minimizing meat discoloration of  claim 1 , wherein the master bag comprises oxygen scavengers placed outside the meat trays.  
     
     
         10 . A method for packaging meat to minimize meat discoloration from formation of metmyoglobin comprising the steps of: 
 packing a master bag with at least one retail meat tray or a primal or sub-primal cut of meat, said master bag constructed of a material exhibiting gas permeability for oxygen of less than 10 mL/m 2 /24 hours at 23° C. and including oxygen scavenger material self-activated in an atmosphere of greater than 70% relative humidity to reduce the oxygen half-life within said master bag to two hours or less after sealing, achieve a zero oxygen storage atmosphere within 24 hours after sealing, and able to function at a temperature range of between 28° and 40° F.;    flushing said master bag with a non-oxygen gas to reduce the residual oxygen level within said master bag to 5% or less and injecting an oxygen-free gas mixture containing carbon monoxide into the bag prior to sealing said master bag; and    storing said master bag at a temperature of between 28° and 32° F.    
     
     
         11 . The method for packaging meat to minimize meat discoloration from formation of metmyoglobin of  claim 10 , further comprising the step of: 
 packing retail cuts of meat in a retail meat tray comprising a tray with an oxygen scavenger contained in a porous sachet and an absorbent pad over-wrapped with a gas permeable plastic-based film perforated by one or more holes.    
     
     
         12 . The method for packaging meat to minimize meat discoloration from formation of metmyoglobin of  claim 11 , wherein the meat tray is arranged in the order of the oxygen scavenger sachet on the bottom, the absorbent pad in the middle, and the meat on top.  
     
     
         13 . The method for packaging meat to minimize meat discoloration from formation of metmyoglobin of  claim 11 , wherein the meat tray is arranged in the order of the absorbent pad on the bottom, oxygen scavenger sachet in the middle, and the meat on top.  
     
     
         14 . The method for packaging meat to minimize meat discoloration from formation of metmyoglobin of  claim 10 , further comprising the step of: 
 injecting a gas mixture into the master bag comprised of between 0.1% and 5% carbon monoxide, between 35% and 39% carbon dioxide, and between 56% and 64.9% nitrogen.    
     
     
         15 . The method for packaging meat to minimize meat discoloration from formation of metmyoglobin of  claim 10 , further comprising the step of: 
 injecting a gas mixture into the bag comprising between 0.1% and 5% carbon monoxide and between 50% and 99.9% nitrogen.    
     
     
         16 . The method for packaging meat to minimize meat discoloration from formation of metmyoglobin of  claim 10 , further comprising the step of: 
 providing oxygen scavengers sealed in the master bag with a total absorption capacity of between 10 mL and 1000 mL of oxygen per pound of meat inside the master bag.    
     
     
         17 . The method for packaging meat to minimize meat discoloration from formation of metmyoglobin of  claim 10 , wherein the oxygen scavengers comprise: 
 between 15% to 20% iron;    between 20% to 25% carbon;    between 10% and 15% vermiculite;    between 5% and 10% de-ionized water;    between 5% and 10% NaCl salt; and    between 0% and 10% zeolites.    
     
     
         18 . A method for packaging meat for long-term storage, comprising: 
 packaging meat cuts, inside or outside of a retail meat tray, inside a sealed master bag used for storage and transport;    flushing oxygenated air from the master bag to obtain an initial atmosphere containing less than 5% residual oxygen;    injecting into said master bag a nitrogen gas rich mixture of greater than or equal to 50% nitrogen and further comprising between 0.1% and 5% carbon monoxide;    sealing said master bag, which contains oxygen scavengers for absorbing the residual oxygen with an absorption capacity of between 10 mL and 1000 mL per pound of meat sealed within the master bag and sufficient for a residual oxygen half-life of less than or equal to 2.0 hours that reduces the residual oxygen level to 0 ppm within 24 hours of sealing; and    storing said master bag at a temperature of between 28°-32° F.    
     
     
         19 . The method for packaging meat for long-term storage of  claim 18 , wherein the oxygen scavenger comprises: 
 less than 25% iron;    less than 35% carbon;    less than 20% vermiculite;    less than 10% de-ionized water; and    less than 10% NaCl salt.    
     
     
         20 . The method for packaging meat for long-term storage of  claim 18 , wherein the oxygen scavenger comprises: 
 between 15% to 20% iron;    between 20% to 25% carbon;    between 10% and 15% vermiculite;    between 5% and 10% de-ionized water;    between 5% and 10% NaCl salt; and    between 0% and 10% zeolites.    
     
     
         21 . A method for packaging meat in a zero-oxygen storage environment, comprising: 
 packaging meat cuts on meat tray having a gas-impermeable film sealed over the top of the meat tray;    sealing said meat tray in a high nitrogen gas rich environment minimizing trapped oxygen to no more than 5% residual oxygen;    sealing within said meat tray an oxygen scavenger for absorbing residual oxygen with an absorption capacity of between 10 mL and 1000 mL per pound of meat sealed within the meat tray and sufficient for a residual oxygen half-life of less than or equal to 2.0 hours that obtains a zero-oxygen storage environment within 24 hours of sealing; and    storing said meat tray at a temperature of between 28°-32° F.    
     
     
         22 . The method for packaging meat in a zero-oxygen storage environment of  claim 21 , wherein the meat tray further comprises an absorbent pad sealed within.  
     
     
         23 . The method for packaging meat in a zero-oxygen storage environment of  claim 21 , wherein the nitrogen gas rich environment is 100% nitrogen.  
     
     
         24 . The method for packaging meat in a zero-oxygen storage environment of  claim 21 , wherein the nitrogen gas rich environment comprises: 
 at least 50% nitrogen;    between 0.1% and 5% carbon monoxide; and    carbon dioxide.