February 2001 

Devices Used to Measure Fat Content in Animal Carcasses 

By: Dick Suiter 

Prior to the NCWM 2000 Annual Meeting, the Grain Inspection, Packers, and Stockyards 

Administration (GIPSA) branch of the U.S. Department of Agriculture (USDA) 

approached NIST and the NCWM to discuss the development of standards for devices 

used to measure fat content in animal carcasses. The NCWM, NIST, and GIPSA began 

discussing possible approaches and the appropriate forum for the development of these 

standards. 

At the 85th NCWM held in Richmond, VA, GIPSA gave a presentation to the attendees 

on the practice of measuring the back fat of hog carcasses in meat packing plants. This 

type of fat measurement is used to adjust the price paid to the producer based on the fatto-lean ratio of a carcass. A premium price may be paid for carcasses with less fat, or a 

lower price may be paid for carcasses with a higher fat content. The fat-to-lean ratio is a 

determinate in what percentage of the carcass the packer is able to deliver to the 

marketplace as normal meat products. The term "yield grade" is a classification of 

carcasses based on the fat to lean ratio. GIPSA reported the value of the hogs slaughtered 

in the United States in 1998 at 8.7 billion dollars. GIPSA anticipates that the same 

devices may soon be used in the beef packing industry. The value of beef in the United 

States slaughtered in 1998 was 25.1 billion. 

There are several different technologies in use by various instrument manufacturers 

today. The original "Fat-O-Meater" is an optical instrument that uses the difference in 

the opaqueness (opacity) of fat and muscle tissue to measure and compute the fat-to-lean 

ratio. This device is the most common in use today. Other technologies include 

ultrasonic units, magnetic resonance imaging (MRI) instruments, and a vision system. 

The ultrasonic units use sound waves to measure the difference in the amount of fat and 

lean. The MRI instruments operate similarly to MRI instruments used in health care 

facilities. The vision system, which is the latest technology, uses video cameras and a 

computer program to determine the amount of fat in a carcass. 

On August 31, 2000, representatives from OWM met with James R. Baker, Administrator 

of the GIPSA branch of the USDA, and members of his staff. This meeting was a 

follow-up to the GIPSA presentation at the Annual Meeting of the NCWM and the 

subsequent meeting with the NCWM Board of Directors. At the meeting, Henry 

Oppermann, Chief, NIST OWM, expressed a concern that the scope of the project may 

exceed the resources of the NCWM and/or OWM. Other standards-writing organizations 

may be a potential source of assistance. The NCWM and OWM may want to be involved 

in the process but not be the responsible party for the development of a standard. 

Considering the commercial implications of use of these devices, the NCWM may at 

some future time wish to consider adoption of NIST Handbook 44 requirements relative 

to specifications, tolerances, and user requirements for the instruments. 
At the January 2001 NCWM Interim Meeting, OWM reported that ASTM was interested 

in being the standards writing organization for the development of the fat measurement 

standard. GIPSA and the NCWM Board of Directors agreed to pursue that avenue. 

On February 6, a meeting was held at ASTM headquarters in Conshohocken, PA, with 

representatives from ASTM, NCWM, GIPSA, and NIST. At that meeting, ASTM agreed 

to develop standards for the measurement of fat in animal carcasses with participation by 

NCWM, GIPSA, NIST, device manufacturers, user groups, and other interested parties. 

A meeting to begin organizing the effort has been tentatively scheduled for the first week 

in April 2001. For further information regarding this issue or to be added to the list of 

interested parties, contact Dick Suiter (NIST) by e-mail at rsuiter@nist.gov or by phone 

at (301) 975-4406.