September 2006 

Inspecting and Testing Electronic Carcass Evaluation Devices 

By Dick Suiter 

This is the third in a series of W&M Quarterly articles intended to familiarize weights 

and measures field officials and administrators with electronic carcass evaluation device 

standards, operation, inspection, and testing. The first article, published in November 

2005, discussed the four documentary standards applicable to electronic carcass 

evaluation devices during inspection and testing in the field. The second article, 

published in June 2006, described the Fat-O-Meat'erTM built by SFK Technology, Inc. 

This was the first device used by the U.S. pork-packing industry for measuring back fat 

and depth of the loin eye. This article and subsequent articles in the series will describe 

additional devices or systems currently in use commercially and others being used in 

non-commercial applications, but which have the potential for commercial use. For each 

device or system the articles will provide an overview of the base technology utilized and 

how the equipment functions, as well as test methods and reference material or physical 

standards currently available for use in conducting accuracy verification. 

Since the 2006 edition of NIST Handbook 44 includes a new tentative code Section 5.59. 

Electronic Livestock, Meat, and Poultry Evaluation Systems and/or Devices-Tentative 

Code, it is important that field officials begin evaluating these devices to determine if any 

changes are needed to the tentative code. 

In this article we will look at the AutoFomTM (automatic Fat-O-Meat'er) built by SFK 

Technology, Inc. This device utilizes ultrasonic energy of sound waves for measuring 

back fat and depth of the loin eye. The measuring principle used by the AutoFomTM is 

one of digitized, three-dimensional scanning. The scanning pattern is provided by 16 

ultrasonic transducers embedded in a fixed stainless steel transducer array. The 

transducer array is located in a stainless steel trough. Carcasses are pulled or slid through 

the trough (Figure 1). As the carcasses pass over the transducer array (Figures 2 & 3), 

the transducers provide a cross-section image for every 5 mm in the length of each 

carcass. Each of the 16 transducers produces approximately 200 measurements for a total 

of approximately 3200 measurements for the average carcass. By sampling all 200 

measurements from one transducer, it is possible to produce a slice of the carcass in the 

length direction. Sampling the slices from all 16 transducers provides a threedimensional image of the back side of the carcass (Figure 3). 

 

Figure 1 

Figure 2 
From the three-dimensional image, (Figure 4) the system software determines, indicates, 

and records measurements of the external fat thickness and the loin muscle thickness. 

Testing of the device is a relatively simple process of conducting linear measurements 

using a "calibration standard" that was developed by the device manufacturer (Figure 5). 

The calibration standard consists of stainless steel rod whose length can be verified by an 

appropriate laboratory. The rod shown in Figure 5 has a nominal length of 100 mm. 

Initial calibration and subsequent testing is conducted by placing the standard on each 

transducer using a small amount of a gel substance to assure sonic transfer. The readings 

obtained should be equal to the length of the calibration standard. 

Figure 5 

The United States Department of Agriculture (USDA) performs tests of the device by 

placing the standard on each of the transducers 10 times and comparing the readings 

shown on the display with the calibrated values for the test block. This procedure verifies 

both accuracy and repeatability. 

Similar, but more detailed test procedures for the AutoFomTM, were approved May 1, 

2006, and added to ASTM Standard-F2343-06. (See the ASTM website at www.astm.org,

or contact ASTM Customer Service at service@astm.org for referenced ASTM 

standards.) The device user is required to maintain a test standard with the device and is 

required to perform this procedure at the beginning of each production day. The 

standards maintained on site by the device user are required to meet the NIST 

Handbook 44, Appendix A Fundamental Considerations Section 3. Testing Apparatus. 

Figure 3 Figure 4 
The user of the device is also required to have the accuracy of the test standard verified 

on an annual basis with traceability to a national standard. Weights and measures 

officials may elect to witness such testing on a periodic basis or may choose to conduct 

their own test using either their own standards or the standards maintained on site by the 

device user. 

Subsequent articles in this series will provide information on other technologies used to 

make measurements of various carcass constituents. These articles will describe devices 

or systems currently being used commercially for making measurements that are used to 

determine the value of harvested animals by the meat-packing industry as well as some 

devices or systems currently being used on an experimental basis, but which may be used 

commercially in the future. These articles will provide information on how the various 

technologies operate and how they are used, as well as inspection and testing procedures 

developed for each type of device or system. 

For further information or questions related to this article, contact Dick Suiter (NIST) by 

e-mail at rsuiter@nist.gov or by phone at 301-975-4406.