Lasting longer, safely
Nov. 3, 2015
Shelf-life extenders can positively impact a company's profitability.
The Food and Agriculture Organization (FAO) of the United Nations estimates that about one-third of the food produced globally for human consumption – approximately 1.3 billion tons every year – is lost or wasted. This is an excess in an age where almost a billion people go hungry. It also represents a waste of the labor, water, energy, land and other inputs that went into producing that food.
Food loss and food waste may be accidental or intentional, but ultimately leads to less food available. In the meat and poultry industry, one of the greatest forms of loss occurs when product spoils and therefore must be discarded. Spoilage can be visual as well as sensory.
“Ensuring adequate shelf life helps the industry reduce markdowns and discards,” says Poulson Joseph, lead scientist and team leader for meat and poultry-antioxidants at Kalsec in Kalamazoo, Mich.
Shelf life can be extended through the use of ingredient technology, as well as proper product handling throughout the supply chain, processing and packaging. These must be used together for maximum benefit, as shelf-life extenders can positively impact a company’s profitability.
They also contribute to a company’s sustainability efforts by reducing food waste. That’s because purchase depends heavily on shelf-life being optimized. The best example is red meat.
“Consumers shy away from red meats if they start to lose their bright red appearance,” says Tom Rourke, senior business development manager at Corbion Purac in Lenexa, Kan. “Although meat starting to brown is still perfectly safe and hasn’t lost any flavor, most people won’t buy it. This makes fresh red meats an ideal candidate for shelf-life extending ingredients.
“Shelf-life-extending ingredients are also very valuable in cooked, sliced meats, which may be stored for several days after opening,” he says. “In these circumstances, the protective effects of the packaging have been lost, so avoiding off-odors and discoloration while continuing to protect against spoilage microorganisms with shelf-life extenders is an attractive proposition.”
Shelf-life-extending ingredients typically improve the keeping quality of foods, according to Joseph. In the case of meat products, there is often an emphasis on the prevention of spoilage bacteria growth while simultaneously ensuring that quality attributes such as flavor, color and texture are maintained.
Rourke adds, “Shelf-life extenders in ready-to-eat (RTE) meat products generally reduce the growth of lactic acid bacteria and other psychrotrophic spoilage bacteria. Normally, these bacteria do not cause illness, but do have a negative effect on product appearance, odor, texture and flavor. Many antimicrobials that are added to processed meat products protect against pathogens and spoilage organisms.”
Formulators should seek out ingredient systems that provide maximum benefits and protection. With RTE products, these systems and usage levels are often product specific.
“As the rising cost of meat production continues to narrow profit margins, it’s crucial for processors to make the best choice when it comes to processing solutions,” says Courtney Schwartz, senior marketing communications manager at Kemin Food Technologies in Des Moines, Iowa. “Manufacturers are looking for solutions to keep meat and poultry products fresher and safer for an extended period of time. They need ingredient solutions that protect a product’s color, flavor and delay microbial spoilage.”
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Highly perishable food segment
Shelf-life extending ingredients are important for cooked, sliced meats since they are usually stored for days. (Photo: Corbion Purac)
Fresh or cooked, meat and poultry products are highly perishable with their shelf-life depending on a variety of factors, including raw material quality, composition, processing, packaging and distribution channel management. When choosing a shelf-life extending ingredient system, one must consider the application, the ingredient’s purpose, the finished product’s target shelf-life and label claims.
For example, fresh meat and poultry products are nutrient-dense substrates with high water activity, making them a target for microbial growth. With fresh products, addressing microbial spoilage is paramount.
“Different types of spoilage bacteria may proliferate, depending on possible contamination during any step of processing and environmental conditions during storage of the unfinished meat product,” Schwartz says.
Oxidation must be addressed in both fresh and cooked products, but the impact of oxidation varies by product. This is because oxidative changes include color deterioration and fatty acid breakdown, both of which negatively impact the sensory attributes of meat and poultry products.
“Meat proteins, specifically myoglobin, undergo oxidative changes during storage and retail display, resulting in meat discoloration in fresh meat products,” Joseph says.
Fatty acid breakdown is more prevalent in cooked meats, as heat initiates the breakdown of polyunsaturated fatty acids (PUFA) present in such products. These fats are highly susceptible to oxidation, which produces unwanted flavor changes in the final product.
For example, oxidation can produce what has become known as warmed-over flavor (WOF), which is odors and flavors commonly described as stale, cardboard-like, painty or rancid. WOF has long been recognized as one of the primary causes of quality deterioration in cooked, refrigerated and pre-cooked frozen meat products.
“WOF is unacceptable to consumers whether they are purchasing pre-cooked meats to be reheated at home, prime rib sandwiches made from yesterday’s prime rib in a restaurant, or heating up leftover pot roast from Sunday dinner,” according to Mary Susan Brewer, professor emerita, department of food science and human nutrition at the Univ. of Illinois in Urbana-Champaign, in a report for the National Pork Board. “As consumer demand for table-ready, reheatable entree items has increased, so have the WOF problem-solving efforts.”
The most common solution is the addition of antioxidants, which protect PUFA from oxidation by sacrificing themselves to the oxidation process. Artificial preservatives such as butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT) and tertiary butylhydroquinone (TBHQ) function as antioxidants and have long been the standard to ensure an economically sensible shelf-life for fully cooked and packaged meat products.
The acetic acid in buffered vinegar has been shown to inhibit L. monocytogenes in hot dogs and other meats. (Photo: Corbion Purac)
These ingredients are still widely used, but many processors are exploring the growing number of more label-friendly options in the marketplace.
This includes tocopherols, a class of vitamin E with powerful antioxidative properties. They have long been used as a natural shelf-life extender in many products and have application in raw meat. Inclusion can be cleanly identified on ingredient statements as vitamin E or mixed tocopherols, usually with a parenthetical explanation of being added to main freshness, so as not to be confused with inclusion for fortification or nutrition profile enhancement.
There are also a number of plant-based extracts that function as antioxidants. Many are identified simply as “natural flavors” on ingredient statements.
Rosemary and green tea extracts are the most recognized for their ability to conserve the appearance, taste and quality of raw and cooked meat products, both refrigerated and frozen. Carefully selected plant breeds enable production of the most potent extracts. Suppliers blend the extracts into the most effective combination for a specific application and desired shelf life.
“These versatile, natural solutions are label-friendly alternatives to traditional tocopherols or conventional synthetic antioxidants commonly used in the industry,” Schwartz says.
At the molecular level, rosemary extract and green tea extract have similar functionality. Their active components exhibit chain-breaking antioxidant activity. The main difference is that green tea extract has a lower negative flavor contribution to the final product. Thus, using a lower level of rosemary extract in combination with green tea extract allows the manufacturer to increase the natural plant extract usage rate, often resulting in an extract blend that performs better than using rosemary alone.
Acerola extract is also proving to be a useful antioxidant in meat and poultry. Extracted from the namesake wild plant grown in tropical and subtropical regions, acerola extract boasts high levels of antioxidant vitamin C.
“Our acerola extract blends delay both lipid and myoglobin oxidation, thereby delaying the onset of color loss and maintaining the desirable color and quality of meat products,” Schwartz says. “When used in combination with rosemary and green tea extracts, acerola is more effective at delaying discoloration than either extract alone.”
The naturally occurring antioxidants and organic acids – mostly quinic and malic – in plums have also been shown to assist with reducing WOF and extending meat and poultry shelf life, according to Tom Leahy, spokesman for Sunsweet Growers in Yuba City, Calif.
He cites the example of a company using plum juice concentrate to extend the shelf life of a honey-brined turkey breast from 14 to 35 days. It does this while improving flavor and consumer appeal, improving moisture retention, obtaining better yield and improving texture.
An emerging plant extract for shelf-life extension in meat and poultry is natural licorice extract. It has been shown to delay the effects commonly associated with oxidation.
Antioxidants are only effective when used properly. This means they must be added to the system before oxidative deterioration of PUFA begins. Oxidation is a chain-reaction process and soon after it begins, there is no turning back for the fat. The fat remains in a continuous cyclical oxidative degradation process that only ends upon termination, which can occur when an antioxidant enters the scenario. But at this point, any degradation that has occurred is permanent. The fat cannot repair itself. If objectionable flavors and odors have developed, they will remain.
“The right antioxidant must be added as early as possible in the process of producing meat and poultry products,” Joseph says. “For ground products, the ingredients are incorporated as direct addition often to the coarse grind. For whole muscle meats, ingredients are added in the brine/marinade that is used for vacuum tumbling or injection-enhancement.”
Antimicrobials, too, must be added early to prevent undesirable spoilage bacteria as well as pathogens from growing.
Purac offers a lactate with diacetate that gets incorporated into the brine added to processed meat products. “It reduces water activity and lowers bacterial metabolism, increasing shelf life by 50 to 100 percent, without adversely effecting product pH, color or texture,” Rourke says. “Data reveals it also inhibits Listeria growth in RTE products for 90 to 120 days.”
Purac offers vinegars, cultured sugars and cultured sugar/vinegar blends that function as natural antimicrobials. “Vinegar is effective against several meat pathogens and most spoilage organisms,” Rourke says. “The active ingredient in vinegar is acetic acid. The art is to buffer the acid adequately so it will not denature meat proteins or reduce product pH. The addition of cultured (corn) sugar to buffered vinegar provides increased effectiveness against meat pathogens and spoilage organisms.”
The company recently introduced an ingredient that combines vinegar and jasmine tea extract. It is typically used at around 1 percent in fresh sausage and ground meats to help extend shelf-life.
“It provides a complete freshness package,” Rourke says. Studies show it extends refrigerated color stability by two to three days, while also controlling fat oxidation to ensure flavor stability.
“We offer liquid buffered vinegar to inhibit bacterial growth and extend the shelf-life of meat and poultry products,” Schwartz says. The acetic acid in buffered vinegar has been shown to effectively inhibit L. monocytogenes in various meat cuts, including raw uncured turkey, cured ham and enhanced pork loin, as well as ready-to-eat deli meats, hot dogs and other smoked and fresh sausages.
“It does this without negatively impacting the texture or flavor of the finished product,” Schwartz says. It can be labeled simply “vinegar.”
Rourke concludes, “Longer shelf life is beneficial in all aspects of the food industry. It enables manufacturers and brand owners to make their products available in more locations and can reduce transport and logistics costs because their foods can be in the supply chain longer and be transported in slower and less expensive ways.
“Retailers can reduce the frequency of their re-ordering and re-stocking,” he says. “And at the consumer end of the supply chain, food waste is reduced because it takes longer to spoil and has later ‘use by’ dates.”