The USDA Food Safety Inspection Service (FSIS) is responsible for the inspection of meat that is sold across state lines. Commerce across state lines is also called interstate commerce. The agency is also responsible for inspection of meat that's sold within the state, or intrastate commerce. However, some states participate in a program called the State Meat and Poultry Inspection program. Under this program they are allowed to do their own inspection as long as their standards are equal to or exceed the federal standards. This is in keeping with the Wholesome Meat Act, otherwise known as the “equal to” act of 1967.  Inspection, whether federal or state, is essential because it ensures a safe meat supply. However, the law does allow certain individuals and food establishments to be exempt. These include:

1. Individuals who are slaughtering their own livestock for their personal use, for family or non-paying guests
2. Custom-exempt establishments that slaughter and prepare livestock for someone else, if that individual does not plan to sell the meat but keep it for personal use
3. Retail stores and restaurants

The USDA gets its authority from the Federal Meat Inspection Act of 1906 and the Poultry Products Inspections Act of 1957. The role of the agency is to ensure that meat slaughtering and processing establishments comply with the following requirements:

1. Maintain and follow proper sanitary standard operating procedures (SSOPs)
2. Follow a HACCP plan
3. Maintain written procedures and practices to prevent adulterated products from getting into the food supply
4. Follow regulatory labeling requirements including safe handling instructions on packages of raw and cooked meat and poultry
5. Follow all other USDA-FSIS regulatory requirements

Along with sanitation and HACCP compliance, the USDA's inspectors also conduct periodic microbial tests to verify that pathogen reduction standards are met and fecal contamination is under control. Based on these tests, the food establishments may need to reassess the adequacy of their HACCP plan. Otherwise, they must reasses their HACCP plan at least annually. Meat products under the USDA’s jurisdiction include cattle, sheep, swine and goat. Meat products that do not fall under USDA’s jurisdiction are regulated by the FDA. These are called non-amenable or exotic species and include wild game (antelope, buffalo, bear, caribou, deer, elk, moose, reindeer) and wild poultry (wild turkey, wild geese, quail, and pheasant). Exotic species  may be voluntarily inspected and receive a mark of inspection by request to the USDA, however the service is not paid for by tax dollars compared to regular inspection, but is done on a pay-for-service basis.  Inspectors must be present at all times in slaughtering facilities and at least part of the shift in operations that involve further processing of meat. When most of you think of USDA inspection, you often think of slaughtering only, but keep in mind that processing facilities such as those producing canned soups containing meat, and pizza with meat topping are also under USDA’s jurisdiction, provided that the meat content exceeds more than 3%. FSIS inspectors at slaughtering facilities routinely conduct antemortem (before slaughter) inspections and postmortem (after slaughter) inspections to verify that the animals that are presented for slaughter are wholesome and free from disease. During antemortem inspection, the animals are held in a holding area under minimum stress, where they are inspected to identify any signs of illness or conditions that could render the carcass unfit for human consumption. Most cattle will pass inspection, however a few may be tagged as "US Condemned" or segregated as “US Suspect”. The ones tagged condemned are those that are already dead, dying or showing obvious signs of disease. They will not be allowed to enter the slaughtering line. The livestock tagged as suspect are those that show signs that they may be diseased. Therefore they are separated to a special holding area for closer antemortem inspection. If they are passed for slaughter, they are usually slaughtered at the end of the shift and the carcass carefully inspected for signs of disease. https://foodsciencetoolbox.com/download/introduction-to-haccp/ The law requires that all livestock must be slaughtered humanely according to the Humane Slaughter Act of 1978. This act mandates that  livestock must be rendered insensible to pain before they are bled. The only exception is ritual slaughter practices such as Halal and Kosher. Under these practices, the throat of the animal is cut with a razer-sharp knife by a single swipe of the hand. The animal losses consciousness within 3 seconds. This is argued to be a more humane method than the captive bolt method or electrocution method to render the animal unconscious. Once bled, the carcass enters a complex dissembling line where USDA inspectors are stationed at fixed positions. Their job is to look for any sign of disease that would render the carcass unfit for human consumption and make sure that they are separated. Postmortem activities involve inspection of the head, viscera, and carcass for signs of abnormalities. If abnormalities are localized, the abnormal tissue may be trimmed. However, if they are generalized, the USDA veterinarian must be notified for inspection and appropriate action. In addition to removing abnormalities, the FSIS inspector must also see to the removal, segregation and disposing of specific risk materials (SRMs). SRMs are tissues likely to contains prion; the protein that causes bovine spongiform encephalopathy (BSE), otherwise known as “mad cow disease”. These tissues include the brain, eyes, spinal cord, tonsils and distal illium (a part of the intestine). These parts of the animal should not be allowed to enter commerce. Carcasses meeting USDA regulatory inspection requirements are stamped with the USDA mark of inspection to demonstrate wholesomeness and compliance with all of the relevant meat processing regulations. The stamp is made from a safe edible purple ink. Only carcass receiving this stamp must be allowed to enter commerce. After the carcass is trimmed and separated into retail cuts you may not see the mark, but the label of the packaged product must bear the USDA inspection mark. So, the next time you shop for meat in your local grocery, look for the mark and be assured that it was inspected by the USDA to guarantee your safety. References:

1. Fortin N. D. (2009). Food regulation - Law, science, policy, and practice. Hoboken, NJ: John Wiley and Sons Inc.
2. Sanchez, M. C. (2015). Food law and regulation for non-lawyers – A US perspective. New York, NY: Springer International.