'Mad cow' prions may permanently contaminate processing plants. A modest proposal

Hi Folks,

The current spin from Big Beef (and their subsidiary, the USDA) is that recall of meat from the first BSE-infected bovine identified through the (inadequate) slaughterhouse spot-testing program will protect consumers from exposure to BSE pathogens.

Bullshit.

All surfaces which were ever in contact with BSE contaminated animal flesh must be regarded as potential permanent reservoirs of infectious prions.

The infectious particles (prions) which cause BSE demonstrate "extreme resistance to conventional inactivation procedures including irradiation, boiling, dry heat, and chemicals" [see National Institutes of Health citation below].

Particles may be inactivated by exposure to superheated steam (132C) at greater than atmospheric pressures....for a mere 4.5 hours. These conditions - exceeding even those found in the studios of Fox News - can be created in autoclaves.

Autoclaves, however, are not terribly practical instruments for the decontamination of industrial food processing plants: the dimensions of slaughterhouses and packaging plants exceed those of the largest autoclaves by a factor of at least 1,000 - 10,000.

Given the practical impossibility of decontaminating BSE-exposed surfaces and equipment, the permanent decommissioning of all facilities involved in the processing of sheep, cattle, deer, elk and/or other "host" animals may be the only way to remove BSE from the US food supply.......

A national repository for contaminated slaughterhouses, meat packing plants, food processing plants, supermarkets, and butcher's shops may prove optimal for management of this grave public health crisis. I propose that the national repository be sited on the Bush family ranch in Crawford, Texas. The proposed site is well suited for the purpose in many respects, not least among which are the facts that:

(1) the location is already under the de facto supervision of Federal law enforcement, and

(2) those residing in proximity to the site have already had opportunity to become inured to the stench of butchery.

Yours,

Kirk James Murphy, MD


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 http://vm.cfsan.fda.gov/~mow/prion.html

The "Bad Bug Book"

U.S. Food & Drug Administration
Center for Food Safety & Applied Nutrition
Foodborne Pathogenic Microorganisms
and Natural Toxins Handbook

Prions and Transmissible Spongiform Encephalopathies

9. Food Analysis & Reconditioning:

 http://vm.cfsan.fda.gov/~mow/prion.html

"No practical detection or inactivation methods exist, at present. The abnormally shaped prions are resistant to most heat and chemical treatments. Decontamination methods are so drastic that food subjected to these processes generally becomes inedible".


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 http://bmbl.od.nih.gov/sect7d.htm

Inactivation of prions. Prions are characterized by extreme resistance to conventional inactivation procedures including irradiation, boiling, dry heat, and chemicals (formalin, betapropiolactone, alcohols). While prion infectivity in purified samples is diminished by prolonged digestion with proteases,(39)(40)results from boiling in sodium dodecyl sulfate and urea are variable. Sterilization of rodent brain extracts with high titers of prions requires autoclaving at 132C for 4.5 hours (h). Denaturing organic solvents such as phenol or chaotropic reagents such as guanidine isothiocyanate or alkali such as NaOH can also be used for sterilization.(41)(42)(43)(44)(45) Prions are inactivated by 1N NaOH, 4.0 M guanidinium hydrochloride or isocyanate, sodium hypochlorite (2% free chlorine concentration), and steam autoclaving at 132C for 4.5 h.(46)(47)(48)(49) It is recommended that dry waste be autoclaved at 132C for 4.5 h or incinerated. Large volumes of infectious liquid waste containing high titers of prions can be completely sterilized by treatment with 1N NaOH (final concentration) or autoclaving at 132C for 4.5 h. Disposable plasticware, which can be discarded as a dry waste, is highly recommended. Because the paraformaldehyde vaporization procedure does not diminish prion titers, the biosafety cabinets must be decontaminated with 1N NaOH, followed by 1N HCl, and rinsed with water. HEPA filters should be autoclaved and incinerated.

Although there is no evidence to suggest that aerosol transmission occurs in the natural disease, it is prudent to avoid the generation of aerosols or droplets during the manipulation of tissues or fluids and during the necropsy of experimental animals. It is further strongly recommended that gloves be worn for activities that provide the opportunity for skin contact with infectious tissues and fluids. Formaldehyde-fixed and paraffin-embedded tissues, especially of the brain, remain infectious. Some investigators recommend that formalin-fixed tissues from suspected cases of prion disease be immersed for 30 min in 96% formic acid or phenol before histopathologic processing,(50) but such treatment may severely distort the microscopic neuropathology.

39. Prusiner S.B., McKinley M.P., Groth D.F., Bowman K.A., Mock N.I., Cochran S.P., Masiarz F.R. 1981. Scrapie agent contains a hydrophobic protein. Proc Natl Acad Sci USA 78:6675-6679.

40. McKinley M.P., Bolton D.C., Prusiner S.B. 1983. A protease-resistant protein is a structural component of the scrapie prion. Cell 35:57-62.

41. Prusiner S.B., Groth D.F., McKinley M.P., Cochran S.P., Bowman K.A., Kasper K.C. 1981. Thiocyanate and hydroxyl ions inactivate the scrapie agent. Proc Natl Acad Sci USA 78:4606-4610.

42. Prusiner S.B., McKinley M.P., Bolton D.C., Bowman K.A., Groth D.F., Cochran S.P., Hennessey E.M., Braunfeld M.B., Baringer J.R., Chatigny M.A., 1984. "Prions: methods for assay, purification and characterization." In: Methods in Virology. Maramorosch K., Koprowski H., Eds. Academic Press, New York, pp. 293-345.

43. Prusiner S.B., Groth D., Serban A., Stahl N., Gabizon R. 1993. Attempts to restore scrapie prion infectivity after exposure to protein denaturants. Proc Natl Acad Sci USA 90:2793-2797.

44. Taylor D.M., Woodgate S.L., Atkinson M.J. 1995. Inactivation of the bovine spongiform encephalopathy agent by rendering procedures. Vet Rec 137:605-610.

45. Taylor D.M., Woodgate S.L., Fleetwood A.J., Cawthorne R.J.G. 1997. Effect of rendering procedures on the scrapie agent. Vet Rec 141:643-649.

46. Prusiner, S.B., et al. 1984. (42)

47. Prusiner, S.B. et al. 1993. (43)

48. Taylor D.M., Woodgate S.L., Atkinson M.J. 1995. (44)

49. Taylor, D.M. et al. 1997. (45)

50. Brown P., Wolff A., Gajdusek D.C. 1990. (38)


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