How to Properly Rib a Pork Carcass

by Wayne F. Gipp

1. The first step in ribbing a pork carcass is the saw cut. Starting at the first rib (shoulder), count up 10 ribs. When counting, be certain that you start at the first rib (fat and/or connective tissue sometimes cover the first rib). Position the saw blade at the body of the vertebra that corresponds to the area between where the 10th and 11th rib bones connect to the backbone.

The saw blade should be placed closer to the 11th rib bone than to the 10th rib bone. The correct saw blade placement will usually be between the mid-point of the vertebra body and one-third of the distance from the top (posterior edge) of the vertebra body.

Position the saw blade perpendicular to the outer skin surface. Do not use the spinal grove as an indicator of perpendicularity, but rather, position the blade perpendicular to backfat side of the carcass (outer skin surface). Saw through the bone using a straight-in angle (0E angle) to a slightly upward angle (10E angle) as illustrated above. To avoid sawing and tearing the loin muscle, stop sawing as soon as you are through the bone.

2. The second step in ribbing a pork carcass is the knife cut. This is accomplished by a single, straight cut starting at the saw cut and finishing 1 to 2 inches beyond the loin muscle. The knife is held with the blade perpendicular to the outer skin surface. Care must be taken to make a smooth knife cut across the loin muscle. A sharp knife is a necessity. The knife cut should be made in a single motion without a back-and-forth sawing motion. The knife cut must follow an imaginary line between the ribs. If, during ribbing, the cut is made too close to a rib bone, the measured size of the expose loin muscle could be reduced by up to 20%. The knife cut should be made using an angle between straight-in (0E angle) and slightly upward (10E angle). A natural tendency among persons ribbing for the first time is to cut slightly downward and contact the 10th rib bone with the knife blade too early. Care must be taken to avoid a large upward angle as well. If a pork carcass is ribbed correctly, the knife should first come in contact with the 10th rib bone between 1 and 3 inches past the end of the loin muscle. However, the cut should not extend more than 1 to 2 inches beyond the loin muscle to avoid devaluing the belly.

Proper ribbing is important to accurate carcass data collection. With a little practice and attention to detail, one can master the procedure of ribbing pork carcasses rather quickly.

NOTE: The evaluation procedures, Fat Free Lean Equations, photos and Quality Standards in this factsheet were adapted with permission from "Pork Composition & Quality Assessment Procedures," published in 2000 by National Pork Producers Council, Des Moines, Iowa.

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