1. Field of the Invention
The present invention relates to the field of animal processing to provide meat food products. More specifically, it relates to methods for reducing leakage of and contamination by matter form the rectum vent of an animal by obstructing the rectum vent.
2. Discussion of the Related Art
Public attention has recently been focused on the microbiological safety of commercially processed meat. Although this country's meat supply has remained consistently safe for many years, with a low incidence of microbial contamination causing illness, governmental agencies responsible for regulation and on-site inspection of commercial meat processing appear to be moving towards a policy of zero tolerance for microbial contamination. Accordingly, sources of contamination, including sources of food-borne pathogens and food-spoilage microbes, and the effects of current processing on contamination have come under scrutiny.
Generally, the origin of microbial contamination in raw meat, such as raw poultry, is the live animal; not the processing facility. The number of microbes found in a retail product is heavily influenced by the microbiological condition of the live animal, which is usually reared in close proximity with many of its kind, making transmission of potentially pathogenic and spoilage microorganisms possible.
The fecal micro flora of animals for slaughter is by far the predominant source of zoonotic microbes such as Campylobacter and Salmonella. Therefore, it is a desideratum for an effective method for reducing gross fecal leakage and contamination during processing.
Modern commercial animal processing generally is a multi-step process employing semi-automated apparatus for transporting an animal sequentially through different, and preferably, physically isolated processing stations to minimize contamination from human sources and cross-contamination between stations. For example, after arriving at a processing plant, poultry are hung by their feet, stunned and then transported through a number of work stations ending with a cleaned carcass being cut into parts suitable for cooking or with the entire carcass being preserved for cooking.
More particularly, in a modern, automated, commercial processing plant, poultry is conveyed through a plurality of consecutive work stations or areas. Typically, the work stations include a slaughtering station where the throat of an invertedly suspended bird is cut and blood is permitted to drain; a scalding station, where the carcass is submerged in heated water to facilitate de-feathering; a de-feathering station, where spinning rubber fingers impact the outside of the carcass to remove the feathers; a washing station, where the exterior of the bird is washed by spraying with an unheated aqueous solution; a hock-cutting station where the feet are removed; and an evisceration station where the internal organs are removed from the remainder of the carcass.
Various measures have been put into place to avoid contamination and cross-contamination of meats during processing and to eliminate microbes introduced by the live animal. However, microbe-free meats have not yet been achieved, a long standing problem being the contamination and cross-contamination of poultry and other meats by the leakage of fecal materials from the rectum vent of the animal during processing.
For example, the de-feathering step can be a major source of contamination of poultry carcasses. As the spinning rubber fingers move from one carcass to another, they may spread fecal material leaked from a few carcasses to many carcasses.
Another step that can be a major source of contamination is evisceration. During evisceration the digestive tract organs are sometimes cut or otherwise opened so that ingesta or fecal material or other contents of the intestine may be released.
One approach to the problem of fecal leakage is to remove fecal matter from the animal to be processed. For example, one method involves squeezing or kneading the large intestine and rectum or cloaca of a poultry animal to force any fecal material out from the poultry animal. This is usually done manually and cannot effectively be accomplished at a rate which is compatible with the desired rates of operation of the conveyors in modern poultry processing facilities.
Another example of this approach involves using a suction probe inserted into the vent of the poultry animal. Loose fecal matter within the vent is supposedly withdrawn by the suction applied to the probe. Suction probes have not been particularly satisfactory, however. The probes often cannot remove all the loose fecal material due to the absence of air within the vent to create an air flow for entraining the fecal matter into the suction probe. Efforts to overcome this problem by increasing the amount of suction can actually work to suck out part of the intestine itself, thereby, damaging the poultry animal often causing fecal leakage instead of preventing it.
Another approach to the problem involves obstructing the opening of the rectum vent. For example, one method includes gluing the vent opening shut. Fecal matter within the vent is supposedly prevented from leaking out through the vent by the adhesive seal. Adhesives have not been particularly satisfactory, due to leakage resulting from, for example, incomplete seals, tearing of the vent opening or adjacent area of the intestine during processing of the carcass.
Another example of this second approach involves inserting neoprene balls into the rectum vent to supposedly block intestinal fluids from leaking. However, such balls have demonstrated themselves to be nonstationary during the subsequent processing of the carcasses. This has resulted in fecal leakage, contamination and cross-contamination of carcasses.
Still another example of this approach is taken with relatively large animals such as cows, pigs, and sheep. A circular cut generally circumscribing the vent opening is made in the carcass and the entire circumscribed vent area is pulled out, pulling a portion of the intestine through the vent cut. The dislodged intestine immediately adjacent the anus or vent opening tied with a string or other clamping means to prevent intestinal leakage during further process steps. One drawback to this approach is that it is only useful with relatively large carcasses. A second drawback is that, even when it is used, it is labor-intensive and not compatible with the desired rates of operation of conveyors used in semi-automated processing facilities.
Therefore, it is a desideratum for a method for reducing fecal leakage and contamination that can simply and effectively be incorporated into the conventional semi-automated processing of slaughtered animals into meat food products. It is also a desideratum for a method that does not preliminarily require the removal or suction of fecal matter from the rectum or the tying of the intestine of the animals to be processed.
Thus, there remains a definite need for an effective method for reducing gross fecal leakage and contamination. There remains a further definite need for methods which may be integrated into modern meat processing facilities to provide reliable, safe and consistent prevention of fecal leakage and contamination. The present invention satisfies these and other needs and provides further related advantages.