Low-Oxygen Packaging of Fresh Meat with Carbon Monoxide: Meat Quality, Microbiology, and Safety
Released January 10, 2008
The American Meat Science Association commissioned this report to bring clarity to the discussion currently taking place within the meat industry and with policy makers and consumers concerning the use of carbon monoxide (CO) as component of fresh meat packaging systems.
Since World War II, Fresh meat was typically packaged using polyvinyl chloride (PVC) film overwrapped trays. More recently, modified atmosphere packaging (MAP) has been developed to extend the retail shelf life of the products. Since 2002, CO has been permitted as a MAP gas for use during distribution in the United States. In 2004, CO was further permitted at low levels as a MAP gas in retail fresh meat packaging. Although use of CO in meat packaging applications is relatively new in the United States, meat products have been exposed to CO as a component of wood smoke for decades. CO also has been used in the United States since the 1970s as a modified atmosphere gas component for shelf life extension of many fresh fruits and vegetables.
Using low levels of CO in MAP systems improves the color stability and flavor of fresh meat with negligible risk of toxicity from the packaging process or consumption of CO-treated meats. The CO-MAP system also prevents premature browning during cooking of the meat, a common problem with some other MAP packaging methods. The CO-MAP packaging system inhibits growth of spoilage and pathogenic bacteria during refrigerated storage and can provide additional protection against bacterial growth after removal from the packaging or if temperature control is temporarily lost during distribution. Evidence also exists that CO-MAP packaging enhances tenderness.
Red color can be maintained in low-CO treated meats that have spoiled, emphasizing the need for adherence to label instructions for product shelf life and the use of odor and overall appearance as spoilage indicators. Overall, inclusion of CO has both advantages and disadvantages that must be thoroughly considered to develop its use as packaging technology benefiting both consumers and the meat industry.