I've been a CU member for many years and really appreciate their product reviews, research and advocacy on behaf of consumers.  As expected, they've been most active on the Mad Cow issue as well as other food safety issues   After reading all of the following BSE documents from their Mad Cow Page,  I'm really proud of/for them!   If you a not a member, please join.  Just their monthly mag. Consumer Reports  is well worth the small fee.

• Consumers Union Offers Advice On Meat Labels That Do And Don't Help Reduce Risk Of Exposure To Mad Cow Disease new  press release (Fri Dec 31 2004)

Better know what the label means if you want to avoid meat from animals feed animal by-products-  Says meat labled "ORGANIC"  and "BIODYNAMIC" is verified to be from animals feed no animal by-products.  The same cannot be said of other labels such as "GRASS FED" or "GRAIN FED".  Study this very nice press release for other potientially misleaing lables and additional info/details.
 
• Mad cow update: How to limit your risk

from Consumer Report December 2003 issue (Wed Dec 24 2003)

This is a very good overview type article which follows the discovery of a BSE infected cow in the US.
A snippet:

Is it safe to eat U.S. beef?
The extent of the risk of human infection is currently unknown. Until more information is available, individuals need to make a judgement about their risk tolerance, according to the food-safety experts at Consumers Union's Consumer Policy Institute. If eating beef is not very important to you, you might want to forgo it until more is known. If you want to eat beef, you can limit your risk by avoiding the foods most likely to carry mad-cow disease: brains and processed beef products that may contain nervous-system tissue, such as hamburger, hot dogs, and sausage. Organic or 100 percent grass-fed beef carries the least risk, since the cattle are not fed any animal remains. Steak and hamburger that's ground while you watch are also lower-risk.


It also addresses eating wild game, such as deer and elk- a snippet:

Unlike the experience with infected cows, there is as yet no direct evidence that eating the meat of deer or elk with CWD actually causes disease in people. Still, test-tube experiments with prions have shown that human infection is theoretically possible. And researchers are investigating the deaths of several people who hunted or regularly ate venison and subsequently succumbed to brain-wasting disease.:


Notes that the CU's Consumer Policy Institute has advocated the following:

• Screen far more cattle for the disease using modern rapid quick tests. The U.S. currently tests about 20,000 cows a year out of a total herd of 97 million. By contrast, in Europe every single animal above a given age gets tested.
• Outlaw the feeding of the remains of any mammal to any animals that humans eat.
• Tighten the law on dietary supplements; it currently allows supplements to contain material from the animal parts most likely to contain the mutant protein.
• Require doctors and hospitals to report all cases of Creutzfeldt-Jakob to the Centers for Disease Control and Prevention.
• Consumers Union Calls for Rigorous Mad-Cow Disease Testing on US Beef

press release (Tue Dec 23 2003)
Commends the government for announcing a potential case of mad cow disease before final test-result confirmation but echos previous CU calls for wider testing.  States concern that the diseased cow made it into the food supply, that processing plants could be contaminated, and that nervous system tissue removed from the animal was sent to be rendered  and thence fed to other animals such as pigs and chickens.  As indicated in other documents, the CU has long advocated a ban on feed mammal derived food to any animals.
 
• Letter to the USDA Regarding Increased Testing for Mad Cow

letter (Fri Jul 18 2003)
This very good letter to the Mad Cow in DC (photo)- has web links to info sources.  Some relevant snippets:
We urge  the USDA to dramatically increase current surveillance for bovine spongiform encephalopathy (BSE), also known as mad cow disease, in the US and to authorize the use of rapid tests. We further urge USDA to take whatever steps are necessary to ensure that no central nervous system (CNS) tissue is present in meat intended for human consumption. We urge you not to open the border to imports of ruminants and ruminant products from Canada until both Canada and the US have taken these steps...

Last year, the Animal Plant Health Inspection Service (APHIS) tested some 19,990 brains for BSE. We feel this number is far too small. There are five rapid tests, based on the use of antibodies to the prion protein, which have been approved for use in the European Union. .... These tests are far cheaper and give results far more quickly than the testing methodology presently used by APHIS......   The diagnostic test based on the CDI appear to be more sensitive and accurate than the other rapid test (see the enclosed paper from October, 2002 issue of Nature Biotechnology)   We urge APHIS to investigate the accuracy and sensitivity of all five tests, and to approve one or more to be used in testing brains of cattle.

Regardless of which estimate (ed: of the number of downers/year- USDA says 195,000, Dr. Prusiner says about 1 million) is correct, we urge the USDA to listen to OIE and, at a minimum, test all “downer” cattle using  one of the rapid tests.
<snip>
In addition, USDA cannot rely on the Food and Drug Administration’s (FDA’s) 1997 BSE feed rule being rigorously enforced.  Because of serious lapses, increased surveillance is needed. The USDA-sponsored Harvard risk assessment of the risk of BSE in the U.S. noted that compliance with FDA’s 1997 BSE feed rule is the most important factor in preventing a BSE outbreak. Yet a pair of reports by GAO—one published in September 2000 (see my summary) and the other published in January 2002 (see my summary)-  have shown how lax FDA has been  in ensuring compliance with the feed rule.

We also believe that USDA should act to ensure that no CNS tissue is found in meat destined for human consumption. We note that the results of the Food Safety Inspection Service’s 2002 AMR survey found that “about 74 percent (25 of 34) of the  establishments tested in the AMR Survey of 2002 had positive laboratory results for CNS tissue in their final beef AMR products”; the other 26 percent had negative laboratory results (see pg. 2 of  http://www.fsis.usda.gov/OA/topics/AMRSurvey.pdf). (it's worse than the CU indicated- see my summary)  The USDA should take appropriate action to ensure that there is zero CNS contamination of meat destined for human consumption.
 

The article notes that the orgin of the BSE infected Angus cow in Canada had not yet been determined and asks: "What has the USDA done to investigate the possibility that this animal came from the U.S.?"
 
• Canada's Problem - and America's

op-ed (Tue May 27 2003)
This op-ed piece appeared in the NY Times just after the Canadian mad cow was found.
• Stated that, "the federal government's defenses are full of gaps"  re: preventing the spread to the US.  Noted that too little testing is done to "...detect a problem that might be small but growing. ".
• Called for banning animal products from all aninal feed as the EU has done and noted:  "Even the remains of an animal known to carry a form of mad cow disease could go into rendered feed, under F.D.A. rules."
• Called for "Congress to require dietary supplements to prove their safety before being marketed."
• Called for making vCJD a CDC reportable disease. in conclusion:  "The bottom line is that the government should act now to protect the food supply. Delay will only allow any potential problem to get worse."

• Consumers Union Michael Hansen's Statement On Mad Cow Disease Found In Canada

press release (Tue May 20 2003)
Commends stopping import of beef from Canada.  Calls for more testing- like in Europe.  Notes that the mad cow was rendered and called for banning feeding animal products to animals.

• CU Comments on Scrapie Eradication Uniform Methods and Rules

 (Sat Aug 18 2001)
• Concerns APHIS proposed rules of 6/27/01 to  reinstitute a scrapie eradication program (scrapie is a TSE- the sheep form of BSE).  Cites recent evidence that scrapie may be transmissible to humans.
• Commenting on the proposed ban on the use of scrapie positive animals for human or animal food:   "This very positive action will partially close a gaping loophole in the FDA’s BSE feed rule (21 CFR Part 589), which permitted TSE positive animals, including scrapie infested sheep and goats, to be used in animal feeds."
• Recommends dealer records be required to be kept for 10 years since "...incubation period is typically between 2 and 5 years for animals exposed at or near birth but is typically longer than 5 years and may exceed 9 years in animals exposed post weaning."
• Cites a  "....recent study that found evidence from strain typing experiments that the agent responsible for a French case of iatrogenic growth hormone-linked CJD looked just like a french sheep scrapie isolate, thus suggesting that scrapie was the ultimate source of this case of iatrogenic CJD"  (Lasmézas et al., 2001 -  Adaptation of the bovine spongiform encephalopthy agent to primates and comparison with Creutzfeldt-Jakob disease: Implications for human health. Proceedings of the National Academy of Sciences, 98(7): 4142-4147)"
• Mad-cow disease. Where do we go from here?

Consumer Reports May 2001 Issue (Tue May 01 2001)
Gives a very good summary of the subject and history of govt. efforts to prevent the spread of BSE here:
'89 Banned imports of live cattle and sheep from countries where mad-cow disease has been reported.
'97 Banned the feeding of certain meal made from cud-chewing animals to other cud-chewing animals, including cows and sheep.
'99  Prohibited blood donations from anyone who had spent six months or more in the United Kingdom from 1980 to 1996.
'01  Prohibited all imports from Europe of rendered animal-protein products, regardless of species.
Calls for the following:
• Ban the feeding of animal remains to food animals.  Prohibit feeding the remains of TSE-infected animals to any animal.
• Require feed mills to keep records longer.
• Require the FDA to do a better job enforcing the existing "feed ban".
• Screen more animals for the disease- notes only 2,717 cows tested in '00.
• Letter to the Food Safety Inspection Service of the USDA regarding Mad Cow Disease

 (Thu Mar 01 2001)
This is a rather long and fairly technical letter by CU's Michael K. Hansen, Ph.D to the USDA's Administrator of  FSIS reguarding research and monitoring to prevent the spread of TSE in both cattle and pigs.
It's very interesting reading, so I've compiled a summary/snippets in as a web page. to give one an overview of what's in it.
• Science, Precaution And Food Safety: How Can We Do Better?

Discussion Paper (Tue Feb 01 2000)
The follow snippet gives an idea of it's subject
A goal of this paper is to help develop a conceptual framework, an intellectually rigorous vocabulary for thinking and talking about the use of precaution in food safety descisions. Such a framework is needed both as the U.S. develops its own positions on this subject, and to help shape the ongoing international discussions.
From the BSE section:
A similar disease (scrapie) has been recognized in sheep for nearly a century, but was never thought to pose a risk to humans.  Other TSEs have been documented in wild deer and elk and in ranch-raised mink, all in the U.S. A number of studies suggest that beef is not the only food associated with CJD risk. Several studies looking at dietary risk factors for patients diagnosed with CJD have found eating pork products and animal brains to be associated with increased risk ^[44]  Four cases of CJD in young men who ate venison and hunted deer have been identified, and the Centers for Disease Control is on the alert for more cases. Two studies have documented CJD cases in people who hunted squirrel and ate their brains ^[45]   In short, the available evidence suggests that TSEs can occur in many species, and humans may be exposed not only by eating beef but also by eating meat (and other tissues, such as brains) of other animals as well.
Some evidence also suggests that a native bovine TSE might have infected cows used as mink food. ^[46]   But BSE has not been officially confirmed to occur here in the U.S., and government policy aims to keep it out if at all possible. The FDA has banned feeding of rendered mammal remains to ruminant food animals, and as noted earlier in this paper, the USDA has condemned two flocks of sheep and a herd of ranched elk, to be sure that they don't spread a TSE to cattle. The USDA has tested the brains of several thousand slaughtered cattle, monitoring to detect BSE if it does appear here. U.S. BSE policy is precautionary, though some consumer organizations have suggested to could be even more so-monitoring could be more extensive, the feeding of rendered remains to any food animals could be prohibited, and the sale of brains for human consumption could be banned, for instance. But overall, BSE is a classic case for invoking the precautionary principle, and the U.S. response has been decidedly precautionary.
Footnotes
44. Bobowick, A.R., J.A. Brody, M.R. Matthews, R. Roos and D.C. Gajdusek (1973), Creutzfeldt-Jakob Disease: A Case-Control Study. Americal Journal of Epidemiology 98:381-394.
Also, Davanipour, Z., M. Alter, E. Sobel, D.M. Asher and D.C. Gajdusek (1985), A Case-Control Study of Creutzfeldt-Jakob Disease: Dietary Risk Factors. Americal Journal of Epidemiology 122:433-451.
Both studies were done in the U.S. Also, a European study that affirms the findings, by C.M. van Duijn, et al. (1998), Case-Control Study of Risk Factors of Creutzfeldt-Jakob Disease in Europe During 1993-1995. The Lancet 351:1081-1085.

45. Berger, J.R., E. Weisman and B. Weisman (1997), Creutzfeldt-Jakob Disease And Eating Squirrel Brains. The Lancet 350:9078. Also, Kamin, M. and B.M. Patten (1984), Creutzfeldt-Jakob Disease: Possible Transmission to Humans by Consump-tion of Wild Animal Brains. American Journal of Medicine 76:142-145.

46. Marsh, R.F. (1992), Transmissible Mink Encephalopathy, Scrapie and Downer Cow Disease: Potential Links. Paper presented at the Third International Workshop on Bovine Spongiform Encephalopathy, Bethesda, MD, December 9-10, 1992. Also, Marsh, R.F., et al. (1991), Epidemiological and Experimental Studies On A New Incident of Transmissible Mink Encephalopathy. Journal of Genetics and Virology 72:589-594. See also two earlier studies by G.R. Hartsough and D. Burger, done in 1966, cited in Marsh's
papers.

• Comments To The FSIS/APHIS Meeting On The Harvard BSE Risk Analysis Project

 (Mon Sep 28 1998)
CU comments at a USDA public meeting to discuss the scope of the BSE risk analysis project.

Noted a previous  8/98 sent a letter containing a series of scientific and policy questions the risk analysis should address.  The comments contain four key points the risk assessment should address.
 

It should address the risk from all TSEs, not just BSE and cites Iindirect evidence that suggests that "an undiagnosed TSE occurs in US cattle" and "a TSE may have occurred in pigs in the U.S"  This is covered in a letter to the FSIS above.

It should look at studies which have connected eating of various meat products with increased risk of sporadic CJD.  Gives a very good overview of existing studies.  Squirrel brains are amoug the foods cited.

It should consider scientific evidence from the past two years that suggests that TSEs may be more problematical than we thought. Cited is work involving in-vitro conversion of the normal form of the prion to the abnormal, protease resistant form associated with disease and work showingt BSE and scrapie were capable of converting normal human prion protein to the abnormal form.  Also seems to cite evidence questioning the allowance of feeding pigs and chickens food derived from cattle and notes that this is allowed by the feed ban.

Notes that the assumption that TSEs are not in the food supply and do not pose a potential threat to human health because the incidence of CJD deaths has not risen over the years is questionable.  Notes misdiagnose of CJD- in  99 cases studied, only 8 were initially diagnosed as CJD,  "The most common initial diagnoses were stroke (18), depression (13), dementia (10), unknown (6), and Alzheimer's disease (5)."  Also cites other studies indicating misdiagnose-   one autopsied 54 patients diagnosed as having probable or possible Alzheimer's or some other dementia (but not CJD) and found 3 cases (or 5.5%) were actually CJD.  The other found autopsied 46 patients diagnosed with Alzheimer's and found 6 (or 13%) were CJD.
concludes with:  "Since there are over two million cases of Alzheimer's disease currently in the United States, if even a small percentage of them turned out to be CJD, there could be a hidden CJD epidemic. "

The document is well footnoted
 

• Questions And Answers On Proposed FDA Regulations On Animal Feed

 (Wed Jul 01 1998)
Consumers Union believes that the FDA should ban the use of all mammal protein from the feed of all animals intended for human consumption.

This is an EXCELLENT paper- a definite "must read"!  Has a great overview of TSE/BSE.  Some interesting snippets.
 

What is the infectious agent?
While the cause of TSEs has not been definitively established, the most widely accepted theory is that the infectious agent is an abnormal form of a naturally occurring protein, called a prion. Prion proteins normally occur on the surface of nerve cells and lymphocytes. When an abnormal prion comes in contact with a normal prion the normal one converts to the abnormal form. This can continue in a kind of domino effect. The conversion of many prions damages the nervous system. The gene that results in animals producing prion protein has been identified, and has been found in all mammals looked at so far.
Most experts believe some TSEs occur naturally as a result of spontaneous mutation in the prion gene. If a spontaneous mutation occurred in a food animal, the practice of feeding the remains of slaughtered animals back to other food animals could result in a single diseased animal infecting many additional animals.
What should FDA do?
FDA has instituted a partial ban on feeding mammal remains to ruminants, exempting swine and horses, as well as all blood, milk and gelatin. This is inadequate. In a number of studies, blood has been shown to carry the infectious agent. Under FDAs' proposed rule, rendered remains of cows and other food animals could be fed to pigs, and vice versa. Even animals known to harbor at TSE infection could be fed to swine and poultry. Thus an infectious agent could circulate among food animals.

CU recommends that FDA prohibit feeding any mammal protein to any food animal, thus greatly reducing the possibility of a TSE disease circulating among food animals.

The UK banned feeding of ruminant remains to ruminants in 1988. Subsequently BSE in UK cattle declined but was not eliminated. In 1996, the UK banned feeding of all mammal protein to all food animals.

If infectious prions were circulating in the food supply, wouldn't we know it?
Because TSE's have relatively long incubation periods during which animals show no symptoms, farmers and meat inspectors   would not necessarily know if an animal were infected. Most food animals are slaughtered at an early age before any obvious disease symptoms would appear.

The U.S. Department of Agriculture (USDA) has looked at more than 5,000 cattle brains since 1993 and not detected BSE.  However, the majority of the brains were only examined visually for signs of disease, and were not subjected to a more sensitive biochemical test. The animals may have the disease and be infectious for several years before any visible symptoms appear and even before molecular tests could detect the disease. TheUSDA's surveillance systems thus will not pick up cows in the early stages of infection. USDA has no program for monitoring swine brains.
 

• The Reasons Why FDA's BSE Feed Rule Won't Protect Us From BSE

 (Wed Jul 01 1998)
Originally appearing in the 7/97 Genetic Engineering News

Notes that  susceptibility to TSE may have a genetic basis.

States that the ban permits the rendered remains of pigs and horses to be fed to cows and sheep, and vice-versa.  Notes that the EU (except  Denmark) has banned use of all mammalian meat and bone meal (MBM) in any ruminant feed.

"FDA exempted swine because no "naturally occurring" TSE has yet been positively identified in pigs under natural conditions. However, this could just mean that the government has not looked hard enough. In a British experiment, a pig injected with brain material from a BSE cow contracted a TSE."  Notes that there is no US monitoring of pigs for TSE yet "Scientific evidence from the US suggests that swine may actually already be infected with a TSE."

"Perhaps the most egregious problem with the FDA rules is that they would permit known TSE-positive material to be used in pet food, pig, chicken and fish feed--FDA only requires that it is labeled "Do not feed to cattle and other ruminants." Thus, carcasses of scrapie-infected sheep and TSE-infected deer could legally be sent to the renderer and converted into pet and pig rations."  and notes that "WHO urged that "No part or product of any animal which has shown signs of a TSE should enter any food chain (human or animal)."

Notes that the US ban on UK MBM may be in danger via GATT since domestic TSE postive materials are permitted as feed.  Also noted that EU countries could ban US meat because our feed law is substandard.   (i've not seen anything indicating either of these two things actually occurred).

CU beleives all TSE-positive material should be incinerated.

CU disagrees with the FDA's exemption of blood and blood products from the ban citing an experiment where blood from mice infected with CJD injected into the brains of healthy mice caused them to develop a TSE.

The rule should include gelatin, which comes primarily from the hide of pigs and cows.   As an excellent reason, it is noted that FDA's own TSE Advisory Committee concluded that "not enough scientific evidence exists to state that gelatin does not contain the TSE-causing agent and voted 10-to-3 that FDA should withdraw its exemption of gelatin from current regulations on BSE-derived materials".  It also notes that this committee was not asked to review the feed rule.
 

• The Jury Verdict in Cattlemen v. Oprah Winfrey

press release (Thu Feb 26 1998)
A snippet:
"Oprah Winfrey and Howard Lyman each deserve credit for standing and fighting against the strong arm tactics of the plaintiffs in this case. Although the Texas law was not struck down, putting up a strong defense and acting to galvanize public opinion in favor of the first amendment and against corporate bullying will thaw at least some of the chill created by this law."
Amen!
 
• Can It Happen Here? The Puzzle of Mad Cow Disease

Consumer Reports Article (Tue Jul 01 1997)
(I've not reviewed this)
 
• Consumers Union Criticizes FDA Decision on "Mad-Cow-Disease" Rule

press release (Tue Jun 03 1997)
This press release echos much of the previous CU positions on the "feed ban".  Some snippets/comments:
 
"By failing to include swine in the rule, FDA has left the door open for a mad cow-like disease to circulate in the United States,"   Discusses why a wider ban is needed.  Notes the UK and EU have banned  feeding the rendered remains of any mammal to all food animals.

"FDA claims that its rule will prohibit "nearly all" mammalian protein from being used in ruminant feed. Consumers Union points out, however, that swine protein constitute 16 percent of all rendered protein."

In concluding, a scorcher:
 

"The epidemic in the United Kingdom involved 10 years of bureaucrats ignoring the warnings of scientists and underestimating the seriousness of the risks. The FDA seems bent on repeating those mistakes," Hansen says.
• Journalist Letter Regarding FDA Approved Regulation

 (Sun Jun 01 1997)
States that CU "is concerned because the FDA has exempted swine from its ban on feeding animal remains to food animals, which appears to leave the door open to just such an outbreak.", provides backgroud info to journalists and offers interviews with knowledgable CU staff.
 
• Consumers Union's Comments on Docket No. 96N-0135, Substances Prohibited for Use in Animal Food or Feed

 (Mon Apr 28 1997)
These were comments on the draft FDA "feed ban".  The document is a long and pretty technical article but well worth a read.
I've not yet analysed the final rule or FR notice to see how the CU concerns were addressed.
Some snippets:
 
"We think that this draft rule sends a particularly dangerous message. The draft rule suggests, that of all mammals, pigs are the safest and/or least likely to be infected with a TSE. We think this message is incorrect."

"The FDA should ban the use of all mammalian protein, including porcine protein, blood and gelatin, from all feed intended for food animals (not just ruminant feed), as has been done in the United Kingdom. Anything less than this leaves open the possibility that a TSE could, in fact, spread among food animals in the United States."
 

Highlights:
1979 USDA study of pigs with Central Nervous System (CNS) symptoms at a NY packing plant and subsequent work which suggests pigs may already be infected with a TSE.

Epidemiological Studies Linking CJD to Pork Consumption.  Cites two human studies which statistically linked CJD to eating pork.  Notes that the stadies were small scale and recommends large-scale studies.  Concludes with: "The fact that evidence from a pig study and human studies both point to a unrecognized TSE in pigs is very disturbing."

Related Data on CJD Incidence  Echos other CU documents indicating CJD may be misdiagnosed as Alzheimer's or other illnesses and hence under-reported.

Exemptions for Blood Products and Gelatin
"In the draft rule, there are five exceptions to the definition of mammalian protein, i.e. five different classes of mammalian protein that would be exempt from the rule. We disagree with three of the five exceptions"  These are

Porcine protein (covered above)
Blood and blood products.   Cites a study showing blood products from CJD victims induced a TSE in guinea pigs and said "not surprising as the prion protein is found on the surface of white blood cells".  Also cited study of blood from CLD infected mice causing TSE when injected into the brains of healthy mice.  The experimeter ".... ttold a final news conference that the risk of blood plasma passing on CJD was small, but still existed"     Notes that since blood contains the TSE-causing agent in CJD, it must be assumed it can contain the agent causing BSE and other TSEs.
Gelatin  Notes this comes primarily from the hide and hooves of cows and pigs.  Noted that the EU recently lifted a ban on UK gelatin but it was quite controversial- basically because "definitive evidence that the infectious agent is not present in gelatin was not available".  Echoed facted cited in another CU document that the a FDA committe on BSE "concluded that not enough scientific evidence exists to state that gelatin does not contain the TSE-causing agent".


Exemptions for renderers  CU objects to three of the labeling and tracking rules:
 

Renderers who use a manufacturing method that deactivates the agent that causes TSEs are exempt.  CU states there is "no manufacturing method that is known to completely deactivate the infectious agent..."  Another problem is the dificulity in testing for the abnormal prions.

Products that tested positive for the agent are only required to be labeled "Not for Use in Animal Feed."- not destroyed, hence, it could be used for other purposes such as a fertilizer or possibly in cosmetics.  CU says such stuff must be destroyed and noted that the UK banned the use of bone and blood meal as fertilizer.

Renderers that exclusively use "a method for controlling the manufacturing process that minimizes the risk of the TSE agent entering the product." are exempt.    CU states this is  unacceptably vague and "We shouldn't be talking about "minimizing" the risk of a deadly disease-causing agent entering the feed; we should be talking about preventing it."   (AMEN!)