Meat foods form an important source of proteins and other nutrients for more than half the population in the world. They are obtained mostly from farm raised animals like beef, lamb, sheep, pork, poultry, turkey, veal etc, each having its own characteristics liked by different consumers. Organized farms with tight control and technology intensive operations are supposed to keep the animals disease free, well fed with scientifically formulated animal feeds and slaughter them under humane conditions as per international guidelines. Traditional free grazing is practically non-existent to day, replaced by the much maligned"factory farming" which is amenable to large production of meat with rigid quality and safety parameters to ensure the protection of health of the consumer from food borne diseases.
Traditionally animals are still slaughtered in many developing countries in municipal abattoirs and the dressed carcass in fresh condition is hung from hooks in thousands of small retail kiosks for selling the cuts to consumers on the spot. The fresh meat is generally cooked same day though some keep them in the refrigerator for a day or two. In contrast the organized meat industry uses better slaughter house facilities and process the carcass in well protected processing units for freezing and retailing. Export consignments, in frozen condition have to meet strict hygienic and sanitary over seeing to ensure that they conform to buyers' specifications. Global trade in frozen meat foods form a substantial portion of food business.
In many western countries processed meat cuts are well protected from light, oxygen and other spoilage factors and retailed through super markets with well controlled refrigerated modified atmosphere packs (MAP) and equipped with efficient frozen storage and display facilities. While fresh cuts are universally preferred, the processing and distribution compulsions make it difficult to deliver the products same day. Meat preserved under MAP and cold conditions can be as old as a week when the consumer lays his hands on them in the super market shelves while frozen versions have comparatively longer life in commercial freezers.
Cured meat with nitrites exhibits bright color but these products are not gaining acceptance because of presence of salt and other chemicals used in the curing solution. With the advent of modern technology fresh meat products with attractive color and other desirable quality features have replaced the traditional ones. Color is the single most important factor that attracts a consumer and different sources of meat have varying hues of red color typical of them. Beef cuts are cherry red in color, lamb dark cherry red, pork grayish pink and veal pale pink. As the color imparted by the pigment myoglobin is not stable in presence light, UV rays and oxygen under ambient conditions, meat processors take sufficient care to preserve the desired color through controlled processing conditions. Under adverse conditions both Myoglobin and Oxymyoglobin, the pigments that impart color are converted to Metmyoglobin with a brownish red hue not considered the hall mark of fresh meat. Color stabilization is generally achieved through lower temperatures, MAP conditions and well protective packing materials.
Current practice is to use MAP system with high oxygen content, about 80% of the gas mixture so that the bright red meat color is preserved under refrigerated temperatures. However high oxygen levels can also increase the incidence of oxidative changes in the meat generating off flavors, marring the over all quality of the product. Recent discovery that the desirable color in ground beef can be maintained by incorporating about 200 mg per kg tannic acid has opened up new opportunities to offer better products to the consumers as per their expectations. Use of polyphenols like tannic acid allowed for use under the GRAS regime prevents lipid oxidation while allowing oxygen to stay in the MAP at levels as high as 80% desirable for maintaining the optimum quality. Tannic acid polyphenols have been reported to have superior radical scavenging and shield the product from lipid oxidation activities in fish also and their use in ground meat preparations should offer same advantages.