In the process of moving meat producing animals from the production facility to the packing plant, animals are removed from the holding area (coop, pen, barnyard, etc.), moved down a narrow alleyway, and driven through a loading chute onto a livestock trailer. Animals are then transported for a variable number of hours to a packing facility where they are unloaded from the livestock trailer. The meat producing animals then are moved to a scale, weighed, often tattooed or branded, and moved to a holding area (coop, pen, barnyard, etc.). After a rest period of a variable number of hours, the meat producing animals then are moved into the slaughter area. This process of moving meat producing animals usually is quite stressful to them. Many stressed meat producing animals walk slowly, thus getting in the way of other meat producing animals, while some of the stressed meat producing animals exhibit extreme responses resulting in their inability to move or even death.
Moreover, the sensory qualities of the meat from meat producing animals that were stressed prior to slaughter are not as high as they would otherwise have been, all other factors being equal. Typically this is because more of the animal's muscle glycogen is broken down to glucose than with an unstressed animal. Subsequent metabolism of the glucose results in the formation of lactic acid. Lactic acid formation causes the pH of the muscle cell to drop. In living animals, the lactic acid is metabolized, thus causing the pH to return to normal, higher levels. If the excess lactic acid is not removed from the muscle cells, for example because the animal has been slaughtered, or if the bloodstream is not able to handle the excess lactic acid, a generalized acidosis may occur. If severe, acidosis may lead to death of a living animal.
In animals that already are dead (whether of natural causes, stress-induced reactions, or humane slaughter), an excess of lactic acid, if not removed from the cells, will cause the muscle pH to drop, thus causing the meat to taste and look less desirable. The industry-wide average pH of slaughtered meat producing animals is approximately 5.75 after 24 hours ("ultimate pH"). The pH of animals that have experienced a stress reaction shortly before death is typically in the range of 5.3-5.4 or even lower. Many researchers have attempted to increase the pH of animal meat by various methods, and some have used epinephrine.
It is well known in the art that hormones from the adrenal gland can have a strong influence on animal metabolism and homeostasis. Adrenal hormones help animals to cope with stress through a series of reactions that increase circulation and help provide energy to the muscles. Epinephrine is one of the major adrenal hormones. The natural release of epinephrine readies the animal for stressful situations. Epinephrine binds to the muscle cell, and stimulates the breakdown of glycogen into energy rich compounds, allowing the animal's normal metabolism to dissipate the lactic acid before the animal is slaughtered.
No one previously has been able to acclimate a meat producing animal headed for slaughter in an easy, economical, and efficient manner such that the group of animals so acclimated include fewer slow-walkers and prematurely dead animals, and the animals from a group that have been so acclimated yield meat that is consistently of high quality in terms of taste and appearance. No one previously has been able to produce animal meat with a pH consistently higher than 6.3. In an un-treated group of pigs, for example, very few will have a pH higher than 6.3, while many will have a pH in the 5.5 range.
Accordingly, there has been a long-felt need for a solution to this problem. No one has yet developed a commercially viable solution that can be used by farmers and slaughterers. Moreover, the federal Food and Drug Administration has not yet approved the regular use of epinephrine or epinephrine-like drugs in meat producing animals to reduce stress.
An additional benefit of acclimating the meat producing animals prior to the stress-inducing event is that often stress causes livestock (such as pigs, cattle, and poultry, for example) to shed salmonella. By avoiding the stress reaction, the meat produced by the claimed method will be less contaminated with salmonella.