- - AGRICULTURAL CORE CURRICULUM - - (CLF200) Core Area: ANIMAL SCIENCE (CLF290) Unit Title: MEAT GRADING ____________________________________________________________________________ (CLF291) Topic: MEAT GRADING Time Taught in Year(s) 3 hours 1 ____________________________________________________________________________ Topic Objectives: Upon completion of this lesson the student will be able to: Learning Outcome #: (H-2) - List the USDA grades for beef, pork and lamb. (H-3) - Explain how the USDA criteria are used to grade beef, pork and lamb. (H-4) - Rank at least three different groups of livestock products based on quality differences in a laboratory setting. Special Materials and Equipment: Samples of meats having different qualities. Hamburger, pork chops and rib-eye steaks are discussed in lecture. Copies of Handouts 1-4 for all students. References: Forrest, John C., et al, PRINCIPLES OF MEAT SCIENCE, 1975. Evaluation: Quiz by instructor, and evaluation of the products studied in class. TOPIC PRESENTATION: CARCASS GRADES 1. Carcass Grades A. Beef 1. Two types of grades: a. Quality grades, 1) reflect the differences in the eating quality of meat based on: a) marbling scores - the amount of fat interspersed in the muscle. b) maturity scores - reflects the age of the animal at slaughter. b. Types of quality grades: 1) Prime - This carcass has superior marbling, proper carcass conformation, and adequate maturity. This grade of meat is found in fine restaurants and gourmet stores. a) Beef of this grade is not economical for the meat packer because the cattle are required to get very fat to obtain enough marbling and only a small percentage of cattle meet the conformation standards. 2) Choice - This is the most economical and most desirable carcass grade. a) Adequate marbling and carcass conformation are required. 3) Select - (Used to be called "Good") This beef may be referred to as "no-roll" since it isn't stamped with the USDA grade. a) Must have slight marbling. b) This meat is inspected but not marked with a stamp as Prime and Choice, so it can be sold under store names such as Five Star Beef etc. 4) Standard - Usually older animals and thin animals. a) Minimum marbling or below average carcass conformation fit into this category. 5) Commercial - Includes the designations of: cutter, canner and utility. a) This meat is usually processed into lunch meats, soup, and canned meat products. 6) Cull - Not acceptable for human consumption. (Here Fido...) b. Yield grades 1) Identify carcasses for differences in "cutability" or yield of boneless, trimmed retail cuts. Yield grade is determined by the following measurements: a) hot carcass weight, b) external fat (measured as back fat over the 13th rib) c) percent heart, kidney and pelvic fat, d) rib eye area. 2) Types of yield grades: 1,2,3,4,5,. a) Yield grade 1 being the leanest, heaviest muscled carcass and yield grade 5 being the lightest muscled fattest. c. See Supplemental Handout #1 and #2 B. Sheep 1. Quality Grades a. Similar to beef but depend more on maturity. The grades for lamb include Prime, Choice, Select, and Commercial. b. There are 3 maturity grades: 1) lamb, 2) yearling mutton, 3) and mutton. c. Consumers in the U.S. demand almost exclusively, lamb. Most lambs grade Choice. 2. See Supplemental Handout #3. C. Swine 1. Quality Grades a. There are two considerations in quality grading swine carcasses; 1) quality of the lean meat, 2) and belly thickness. b. Grades for carcasses that have acceptable lean quality are listed below. The different grades are determined by backfat thickness, carcass length as well as yield of lean cuts. They are; 1) U.S. No. 1, 2) U.S. No. 2, 3) U.S. No. 3, 4) U.S. No. 4. c. Carcasses having unacceptable lean or bellies that are too thin are graded U.S. Utility. Sows also fit this category. d. Carcasses from boars or stags have a strong "sex" odor and are not passed for use as human food. __________________________________________________________ ACTIVITY: 1. Evaluate meat products, for example, compare common hamburger (30 percent fat) and ground round ( 18 - 20 percent fat) Compare untrimmed porkchops from a U.S. No.1 hog and a U.S. No. 3 hog. Compare Rib-eye steaks from a Choice carcass and a Select "no-roll" carcass. __________________________________________________________ Supplemental Handout #1 CLASSIFICATION AND GRADES OF SLAUGHTER CATTLE ______________________________________________________________________________ SEX AGE WEIGHT GRADES ______________________________________________________________________________ Vealers: Less than Light Prime, choice, select, Bulls 3 months Medium standard, utility, cull. Heifers Heavy Calves: 3 to 8 months Light Prime, choice, select Bulls Medium standard, utility, cull. Heifers Heavy Steers Yearlings Light Prime, choice, select, Medium standard, utility, Heavy cutter, canner. 2 years or Light Prime, choice, select, older Medium standard, utility, Heavy cutter, canner. Heifers Yearlings Light Prime, choice, select, Medium standard, utility, Heavy cutter, canner. 2 to 3 years Light Prime, choice, select, old Medium standard, utility, Heavy cutter, canner. Cows Older than All Choice, select,standard, 3 years Weights commercial, utility, cutter, canner. Bulls Yearlings All Choice, select, Weights standard, commercial, utility, cutter, canner. 2 to 3 years Light Choice, select, and older Medium commercial, utility, Heavy cutter, canner. Stags All ages All Choice, select, Weights commercial, utility, cutter, canner. Supplemental Handout #2 BEEF QUALITY GRADES Yield Grade 1. - A carcass in this group has only a thin layer of external fat over the ribs, loin and rump, and slight deposits of fat in the flanks and the cod or udder region. Muscles are usually visible through the fat in many areas. Yield Grade 2. - A carcass in this group is nearly completely covered with fat, but the lean is plainly visible through the fat over the round, the top of the shoulder and the neck. Yield Grade 3. - A carcass in this group in completely covered with fat. The lean is visible through the fat only on the neck and the lower part of the outside round. There usually is a thick layer of fat over the loin, rib and the inside round. Yield Grade 4. - These carcasses are completely covered with fat. The only muscles visible are those on the shanks and over the outside of the plates and flanks. There usually is a moderately thick layer of fat over the loins, rib, and the inside round. Yield Grade 5. - These carcasses have more fat on all the various parts, they have a smaller rib eye area and more kidney, pelvic and heart fat than carcasses that will meet the standards for the higher grades. Supplemental Handout #3 MARKET CLASSES AND QUALITY GRADES OF SLAUGHTER SHEEP ______________________________________________________________________________ Sheep or Sex Age Weight Pounds Quality lambs Grade ______________________________________________________________________________ Sheep Ewes Yearlings Light under 90 Prime, choice, Medium 90 - 100 select, Heavy over 100 utility, cull. Mature Light under 120 Choice, Medium 120 - 140 select, Heavy over 140 utility, cull. Wethers Yearlings Light under 100 Prime, choice, Medium 101 - 110 select, Heavy over 111 utility, cull. Mature Light under 115 Choice, Medium 116 - 130 select, Heavy over 131 utility, cull. Rams Yearlings All Choice, select Weights utility, cull. Mature All Choice, select Weights utility, cull. Lambs Ewes, Light under 70 Prime,choice wethers,hot-house select, lambs, rams. utility, cull. Ewes, wethers Medium 71 - 95 Prime,choice Spring lambs, select, Rams. utility, cull. Ewes, wethers Heavy over 96 Prime, choice, lambs, rams. select, utility, cull. Supplemental Handout #4 MARKET CLASSES AND GRADES OF HOGS & PIGS ______________________________________________________________________________ Use Sex Weight Grades ______________________________________________________________________________ Hogs Slaughter hogs Barrows Under 180 U.S. No.1,2,3, and gilts & 4. Barrows 181 - 260 U.S. No.1,2,3, and gilts & 4. Barrows over 261 U.S. No.1,2,3, and gilts. 4 & utility. Sows over 270 U.S. No. 1,2,3, and up to 600. 4 & utility. Boars All Weights Ungraded Stags All Weights Ungraded Feeder hogs Barrows 120 - 180 U.S. No. 1,2,3, and gilts 4 & utility. Pigs Slaughter pigs All classes Under 30 Ungraded 30 - 60 Ungraded 60 - 100 Good,Medium Cull. Feeder pigs Barrows Under 80 U.S. No.1,2,3, and gilts 4 & utility. 80 - 100 U.S. No.1,2,3, 4 & utility. 100 - 120 U.S. No.!,2,3, 4 & utility. EXPECTED YIELD OF LEAN CUTS BASED ON GRADE ______________________________________________________________________________ GRADE PERCENT YIELD ______________________________________________________________________________ U.S. No.1 53 percent and over U.S. No 2 50 to 52.9 percent U.S. No 3 47 to 49.9 percent U.S. No.4 Less than 47 percent. 10/18/88 M. Harris