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Tahitian Fruit Could Extend Meat Shelf Life

For many consumers, color can be the deciding factor when purchasing meat or poultry at the grocery store.  Slightly brown or faded meat may appear to have been sitting on the shelf for too long.

However, color changes are quite normal even for fresh products, maintains the USDA’s Food Safety and Inspection Service (FSIS), which says it is a common misconception that slightly discolored meat is no longer fresh or safe to eat.

Ground beef, for instance, can show signs of discoloration, or brownness, in as little as 36 hours. It is only when discoloration appears in conjunction with an off odor and/or a slimy surface that FSIS warns consumers not to use the meat.

Despite efforts by FSIS, as well as the meat industry, to raise awareness that fading or darkening of meat does not affect its safety, consumers remain hesitant to purchase meat unless it bears the familiar, bright red hue.  Research shows that if meat has 30 percent or more discoloration, consumers will not purchase it.  As a result of this mindset, retail stores experience millions of dollars in lost profits each year.

A recent study performed at the University of Arkansas’ Department of Animal Science may have uncovered a key ingredient that would prevent discoloration thereby extending the shelf-life of meat in retail outlets.

In September 2009, Nathan Tapp, then an animal science major at the University of Arkansas, began a series of research trials using the pulp of a Tahitian fruit called noni (Morinda citrifolia) in ground beef patties. He discovered that the noni pulp, when combined with ground beef, prevented the rapid discoloration that typically occurs.

FSIS explains that when meat is fresh and protected from contact with air, it exhibits a purple-red color that comes from myoglobin, a protein found in muscle tissue and one of the two key pigments responsible for the color of meat. When exposed to air, myoglobin forms the pigment, oxymyoglobin, which gives meat an attractive cherry-red color.

Over time, the continued contact of myoglobin and oxymyoglobin with oxygen, coupled with exposure to bright grocery store lighting, will naturally lead to the formation of metmyoglobin, a pigment that turns meat an unappealing shade of brownish-red or grey. Some scientists have analogized this transformation to the oxidation process of certain metals, or rust.

Jason Apple and Janeal Yancey, Tapp’s supervisors during the course of his research, explained that the antioxidant qualities of noni acted to inhibit this oxidation process in meat. Tapp’s experiments showed that noni pulp effectively enhanced the color stability of the meat, allowing it to remain red after four days.

By experimenting with varying concentrations of noni pulp within the ground beef patties, Tapp determined that a concentration of 5 percent noni by weight within a typical burger could increase its shelf life by at least one to two days.

These findings come at time when there has been a great public outcry over another, more controversial color stabilizer: carbon monoxide. Often associated with the exhaust from an automobile’s tailpipe, many consumers were outraged that this gas was being used in packaging to maintain meat’s red color.

In the earlier part of the decade, consumer advocacy groups urged FDA and USDA to ban the use of carbon monoxide. Alternatively, consumers argued that they should at least have the right to know whether a package of meat was treated with carbon monoxide. At the same time, lobbyists for the meat packing industry fiercely opposed  the ban and the push for labeling requirements.

In an attempt to quell these concerns, FSIS responded to the public with information that the levels of carbon monoxide being used in packaging is harmless to humans. Moreover, carbon monoxide was deemed to be a “fixative” rather than an “additive” since the gas does not impart a color to the meat, but simply maintains its naturally occurring color and dissipates upon opening the package.

Although carbon monoxide currently remains on the FSIS list of safe and suitable ingredients that may be used in specified concentrations in the production of meat, the meat packaging industry is looking ahead toward new technologies that can take the place of carbon monoxide. For this reason, Tapp’s research could prove to one day be the future of meat packaging.

In an interview with Food Safety News, however, Apple and Yancey expressed that a study exploring the effects of noni pulp in ground beef was never intended. Yancey, a program technician at the University of Arkansas, recounted that the Tahitian Noni International originally contacted professors within the Department of Animal Science in 2006 to perform behavioral studies on cattle that had been fed noni pulp.

The product had previously been used in behavioral studies with rodeo horses. Those studies showed that when fed to horses, noni pulp functioned as a calming agent.

In commissioning this study, Yancey indicated that the Tahitian Noni International had hoped the University’s research would show that noni pulp produced a similar calming effect in cattle in order to market the product to both the livestock industry and rodeo circuit. Although the studies in cattle revealed that noni improved weight gain and overall health, there was no indication that the fruit calmed the animals.

Left with buckets of noni pulp in the Department’s laboratory and ground beef that had been donated by Tyson Foods, Yancey considered what effects the noni might have in hamburger patty. It was at that point that Yancey passed the project along to Tapp for further development.

Since Tapp’s discovery, he has gained regional and national attention. In February, he won the southern section of the American Society of Animal Science undergraduate research competition and presented his research in Orlando. He was also awarded the American Meat Science Association’s Undergraduate Achievement Award.

In addition, the Department is currently in the process of seeking a patent on the noni pulp as a food ingredient from the University Patent Committee.

Yet despite the recent acclaim, Apple, a full time professor at the University of Arkansas, noted that there are still a few kinks that need to be worked out before noni pulp could be used in the meat packaging industry. For instance,  ripe noni is considered to have a quite pungent, and to some, even an unpleasant taste and odor. “The taste is not necessarily a deal broker though,” Apple continued.

In the upcoming months, they plan to consult with culinary experts and perform a series of taste tests to get around the flavor issue. Apple and Yancey are both confident that with further testing and guidance from consumer panels, they will be able to minimize the flavor of the noni pulp in the meat.

Apple stated that another step in the research will be to confer with a food safety expert. Presently, Apple said that noni pulp “is FDA approved for human consumption and is approved in the EU as a human dietary supplement.” He anticipates that the product will most likely be safe for consumption since the pureed noni pulp is pasteurized before combining it with ground beef, no related allergen issues have been discovered, and digestion problems occur only when noni is consumed in large quantities.

There remains some uncertainty regarding the cost effectiveness of using noni in ground beef on an industry-wise scale as well as the potential labeling requirements that meat packers will face if and when noni is introduced into the market. Notwithstanding those unanswered questions, however, Apple maintains that the important bottomline is that “noni has the capacity to lengthen the shelf life of meat, which can mean millions of dollars in savings to the retail meat industry.”

Tapp has since graduated from the University of Arkansas with a bachelor’s degree in animal science and an agribusiness minor. He is now pursuing a master’s degree in meat science at Texas Tech University.

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