My Summary/Snippets:

The document is undated, however the PDF file has a 3/03 creation date.  This jibes with the fact that it's a followup to a '02 survey.

Follow-up Results and Actions for the Elimination of CNS (Spinal Cord) Tissues from AMR Products Derived from Beef Vertebrae

Advanced Meat/Bone Separation and Meat Recovery (AMR) systems are designed to remove the attached skeletal muscle tissue from livestock bones without breaking or crushing the bones. This machinery separates meat by scraping, shaving, or pulling the muscle tissue away from the bone. However, unlike traditional mechanical separation, AMR machinery cannot break, grind, crush or pulverize bones to recover muscle tissue. Bones must emerge essentially intact and in natural physical conformation. The AMR process is used to produce meat from beef and pork carcasses.

FSIS policy gives a clear definition of "meat" that does not include spinal cord tissues. Therefore, meat products containing spinal cord tissues are misbranded and possibly adulterated. In December 2002, FSIS issued a directive requiring that routine regulatory samples be taken in beef plants using AMR systems with vertebral columns to ensure that spinal cord tissues are not present in the AMR products. The following survey was conducted in order to determine a baseline for the presence of spinal cord tissues in AMR products derived from beef vertebral columns. The results will guide FSIS in determining whether establishments are preventing spinal cord tissues from being mixed with beef.

Here's the scary part:

However, about 74 percent (25 of 34) of the establishments tested in the AMR Survey of 2002 had positive laboratory results for CNS tissues in their final beef AMR products

But it gets worse- even on retesting, problems were still found:

3.  About 33 percent (22 of 67 tested) of the follow-up AMR samples were positive for CNS tissues.....
4.  About 35 percent (8 of 23) of the establishments submitting follow-up AMR samples tested positive for CNS tissues in their AMR follow-up samples..

The survey indicates that some CNS tissue makes it into human food:

For calendar year 2002, about 92 percent (24 of 26) of the establishments sent their non-compliant (for the presence of CNS (spinal cord) tissues) AMR products to inedible rendering or condemned the non- compliant AMR products. The remaining 8 percent (2 of 26) of the establishments are known to have re- labeled some of their non-compliant AMR products derived from beef vertebrae as mechanically separated beef (MS(Beef). The AMR products were non-compliant because the AMR products tested positive for spinal cord (CNS) tissues. The MS (Beef) was sold for further processing (i.e., chili). It is permissible to re-label if the conditions of the regulatory requirements are met and that spinal cord is expected as a component of this material. It was assumed that the conditions were met, based on actions of inspection program personnel that referenced FSIS regulations (9 CFR 318.18, 319.15).

9... The regulatory requested sampling program for AMR products derived from beef vertebra began the first week of March 2003.....  Currently, the optimum level of this testing procedure for the Eastern Laboratory is about 100 to 110 samples per week, or about 20 to 22 samples per workday.  Initially, all AMR systems producing AMR products derived from beef vertebrae will be randomly tested for CNS tissues at least once every three weeks. Relatively riskier establishments for the presence of CNS (spinal cord) tissues in their AMR products derived from beef bones can be expected to be sampled more frequently than those determined to be relatively less risky.