Premortem inspection is conducted at the abattoir on the day of slaughter to detect and condemn animals that are unfit for slaughter and to note signs or lesions of disease that may not be apparent after slaughter (eg, rabies, listeriosis, or heavy metal poisoning). During inspection, animals should be confined in a lighted enclosure so that they can be clearly observed at rest and in motion. The animals must not be allowed to enter into any area of the facility where slaughtering, dressing, or handling of edible products is performed until they have been inspected and found to be acceptable candidates for human consumption. Gates, chutes, and equipment must be available to segregate abnormal animals for closer examination and proper identification.
Seriously crippled animals, animals commonly termed “downers,” and disabled or moribund animals are not acceptable candidates for slaughter as food. Rectal temperatures should be verified on any animal suspected of being febrile. Body temperature should be <106°F (41°C) for pigs and <105°F (40.5°C) for cattle, sheep, goats, horses, and mules. Animals with signs or lesions that do not warrant immediate condemnation can be identified as “suspects” so that their carcasses and viscera can be inspected separately. Certain animals may be retained to allow recovery from minor diseases or to permit depletion of residues of biologic substances and chemicals. Animals that may have been treated with or exposed to substances that may make the edible tissues unfit for human food should not be slaughtered for such.
Animals that have reacted to a test for anaplasmosis, leptospirosis, or tuberculosis are unacceptable as food. The temperature of bovine tuberculosis reactors should be taken on premortem inspection.
Animals suspected of having a foreign disease or parasite should be held and reported immediately to the nearest federal or state health official.
Animal welfare and humane slaughter concerns are increasingly important to the livestock industry. Slaughtering plants in the USA are routinely observed to ensure full compliance with provisions of the Humane Methods of Slaughter Act of 1978 and related regulations. Humane handling of livestock before slaughter is necessary and includes methods of stimulation, nonabuse by plant workers, provision of food and water, safe pen construction, nonslip floors, and protection from adverse weather conditions.
Most large meat producers require compliance with humane slaughter regulations. Therefore, these animals must be rendered insensible to pain by a single blow, gunshot, or an electrical, chemical, or other method that is rapid and effective before shackling, hoisting, or cutting.
Recognized ritual slaughter methods, such as halal and kosher, are exempted from these requirements.