When you walk through the meat section of a supermarket, you might have noticed that the meat, especially beef, has a bright red, fresh and healthy looking, appearance. Is this natural? Or is there some science behind it? Let’s break it down for anyone interested in the “red mystery” of supermarket meats.
The Color of Fresh Meat
To start, it’s essential to understand the natural color of meat. The primary protein in meat muscles, myoglobin, determines its color. Depending on how much oxygen is available, myoglobin can take different forms:
- Oxymyoglobin: Gives meat a bright red color. This form develops when myoglobin combines with oxygen from the atmosphere.
- Deoxymyoglobin: Without oxygen, meat appears purplish-red. If you’ve ever seen vacuum-sealed beef, this is the color you might notice.
- Metmyoglobin: If meat sits around too long, it may turn to a brownish color, which isn’t very appealing. This form happens when myoglobin oxidizes.
Now, given that consumers associate bright red meat with freshness and quality, supermarkets are interested in ensuring the meat stays nice and red while on display. Here’s how they do it:
- Modified Atmosphere Packaging (MAP): This technology involves changing the mix of gases inside meat packaging. By increasing the amount of oxygen – sometimes up to 80% – the bright red oxymyoglobin form of the meat is promoted. This keeps the meat looking fresh for a more extended period.
- Clear Plastic Packaging: Ever noticed how meat is often presented in transparent plastic trays? This design isn’t just aesthetic. The clear packaging allows oxygen to penetrate and interact with the meat, maintaining its bright red appearance. However, it’s worth noting that if meat stays in this environment for too long, it can turn brown as the myoglobin oxidizes.
- Fresh Cuts: Before displaying meat, supermarket employees might trim off any browned edges, revealing a fresh and bright red layer beneath.
What Gases are used in Modified Atmosphere Packaging?
Oxygen (O2): This is the primary gas responsible for maintaining the bright red color of meats. A high concentration of oxygen (often around 60-80%) promotes the formation of oxymyoglobin, the molecule that gives fresh meat its red hue.
Carbon Dioxide (CO2): CO2 effectively inhibits the growth of bacteria and other spoilage organisms. It can extend the shelf life of the product. However, too much CO2 can adversely affect the color and flavor of the meat, so it’s usually used in combination with other gases in a balanced mix.
Nitrogen (N2): Nitrogen is an inert gas, meaning it doesn’t typically react with meat or with other substances. In MAP, nitrogen is often used as a filler to replace the air within a package, preventing the pack from collapsing and helping to push out other gases that might promote spoilage.
Carbon Monoxide (CO): This gas is a bit more controversial but is used in some places to maintain the red color of meat. Carbon monoxide binds with myoglobin to produce carboxy myoglobin, a bright red complex that can make meat look fresher than it might be. Due to health concerns and its potential to mislead consumers about freshness, the use of carbon monoxide in meat packaging is restricted in some countries.
Hopefully the US Doesn’t Allow Cabon Monoxide in Our Meat Packaging?
Sadly, if does. The FDA has approved carbon monoxide for use in meat packaging in the USA. Carbon monoxide is used as a preservative in packaging for beef, pork, and raw tuna. It is also used in modified atmosphere packaging (MAP) to maintain food quality.
Is Red Always Better?
Though bright red meat often indicates freshness, color alone shouldn’t be the sole factor in determining meat quality. Other indicators like the use-by date, smell, texture, and overall appearance play crucial roles. Furthermore, some meats naturally have different color ranges. For example, venison or bison may be darker than typical beef.
The radiant red hue of supermarket meat is a dance between natural biology and human intervention. While the color can indicate freshness, always look at multiple factors when choosing your meats, keeping in mind that the manufactuer and retailer want you to think the product is super nice and fresh.
The color of meat depends on myoglobin – Michigan State University
Carbon Monoxide in Meat and Fish Packaging – National Library of Medicine