Low-oxygen packaging of fresh meat with carbon monoxide
Packaging of fresh meat with carbon monoxide offers several advantages over aerobic packaging according to a White Paper from the American Meat Science Association.
The paper, authored by Daren Cornforth of Utah State University and Melvin Hunt of Kansas State University, reviews research about this packaging technology and compares it to high-oxygen modified atmosphere packaging and PVC film packaging.
Carbon monoxide (CO) packaging would assuage consumer concerns over meat quality and offers several advantages over aerobic packaging such as red color stability, better flavor acceptability, decreased spoilage and increased tenderness.
Despite these advantages, there is a concern that CO is harmful to the gas' ability of displacing oxygen from the hemoglobin and reduces the oxygen-carrying capacity of blood cells.
Another concern is that CO will give the meat a persistent red colour even after bacterial numbers have reached spoilage level. This could cause consumers to purchase meat that appeared fresh, but was in fact spoiled.
Effect of Packaging Method on Shelf Life
Due to Polyvinyl chloride's (PVC) inhibitory effects of carbon dioxide (CO2) on bacterial growth, both high-oxygen and CO MAP can provide longer shelf life for fresh meats.
Even so, good sanitation practises are required to minimise product contamination, and to minimise bacterial growth, products have to be kept chilled at all times.
Temperature control is also important during storage regardless of packaging method, as CO-MAP is inhibitory to bacteria at a temperature below 10 deg C.
Fresh meat in CO-MAP will eventually spoil. This emphasises the importance that a consumer should keep to the meat's dating system on the label.
Recent Studies on CO Use with Fresh Meats
In Norway's retailing red meat, low CO packaging process had grown to 60 percent. Noting the commercial success and safety of the Norwegian process, the US had a renewed interest in fresh meat packaging using CO.
Both previous and recent studies of pretreated meat showed that duration of red colour stability was affected by process conditions. The red colour of CO-treated meats gradually changed to a discoloured brown when cuts were stored under aerobic conditions whereas meats stored in a CO-MAP environment maintained their red colour for extended periods.
CO Use in Seafood, Fruits and Vegetables
Tasteless smoke was produced by burning wood or sawdust in a smoke generation followed by filtration to remove particulate matter and taste components.
Seafood would be placed in a cold chamber flooded with tasteless smoke, and stored for sometime to gain a preservative effect.
For more than 70 years, filtered smoke had been used on raw fish at cold temperatures. Fish had been both hot and cold smoked for generations, and salmon had been smoked with filtered smoke in Europe and North America for decades.
Salmon was treated with filtered smoke to preserve its colour and texture, and to impart a light smoke taste. Tasteless smoke is a filtered version of the same smoke used in salmon smoke houses for decades.
To prevent browning in packed lettuce, CO use has been licensed in the US. CO is also included in the modified atmospheres of marines transport containers for commodities, in part to kill pests.
Regulatory Status of MAP Gases
From regulatory standpoint, MAP gases are processing aids, not food additives. As such, their uses are not listed on the label ingredient statement.
Currently, consumers are not informed by the packaging regarding use of CO, CO2 and elevated oxygen levels. Options available to better inform consumers on food processes and treatments include mandatory or voluntary listing of compounds used as processing aids. The consumers can also be educated by the industry, media, and retail outlets.
These issues are currently being discussed by both food regulatory agencies and consumers because of the complications involved.
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Source: American Meat Science Association