Mike said:
Big Muddy rancher said:
bse-tester said:
Beefman wrote:
The collection of the sample can be done in a number of ways. The entire exercise it to contain the sample from collection to lab (Chain of custody). I mentioned the Tube method only to point out to Jason that it is easy to collect a sample. The tube is inexpensive and is easily cleaned between samples. Of course, there are those who suggest that cleaning the tube may be a process wherein PrPsc may still be contained within a supposedly cleaned tube, but if the process is adhered to precisely, the tube can be well decontaminated between each animal sample being taken. The cost of the tube is therefore considered to be a 'one-time cost' and the cleaning solutions are such a minor expense that it ireally is insignificant to the cost per test. Another method put forward by some colleagues is to take the urine sample during the slaughter process wherein a typical needle is used to draw say 10 cc's of urine from the bladder. Needles purchased in large bulk quanities are extremely inexpensive - a matter of pennies.
We consider that taking a urine sample by needle along with a slice of the liver and brain is a good way to do it. The urine is processed in the lab whereas the liver and brain section are stored at minus 80 C for a period of approximately 3- 6 months to allow for a reasonable period of time for the meat product to pass through the human food chain. We do appreciate that some products may be stored in the consumer's freezer for periods longer than that, but we have to reach a reasonable time limit for sample storage and 3 - 6 months seems to work well. The reason for storing such samples is to provide for an original sample from the traceable animal in the event that something is found in the urine sample or in the event of questions being raised as to the safety of the meat product. We can provide a hard trail right back to the precise animal that the meat came from and still have original tissue from that animal with which confirmatory tests may be done. At the end of the day, having an animal tested and declared BSE free for a sum of only $20.00 or perhaps less, is a small price to pay to have consumer confidence in your product.
Tell me how the TUBE can be easily cleaned when Surgical instruments have supposedly passed on CJD after being in a autoclave?
Inactivation of Prions by Acidic Sodium Dodecyl Sulfate
David Peretz ,1,2,{dagger},{ddagger} Surachai Supattapone,1,2,{dagger},§ Kurt Giles,1,2,{dagger} Julie Vergara,1 Yevgeniy Freyman,1 Pierre Lessard,1 Jiri G. Safar,1,2 David V. Glidden,3 Charles McCulloch,3 Hoang-Oanh B. Nguyen,1 Michael Scott,1,2,|| Stephen J. DeArmond,1,4 and Stanley B. Prusiner1,2,5*
Institute for Neurodegenerative Diseases,1 Departments of Neurology,2 Epidemiology and Biostatistics,3 Pathology,4 Biochemistry and Biophysics, University of California San Francisco, San Francisco, California 941435
Received 14 March 2005/ Accepted 16 September 2005
Prompted by the discovery that prions become protease-sensitive after exposure to branched polyamine dendrimers in acetic acid (AcOH) (S. Supattapone, H. Wille, L. Uyechi, J. Safar, P. Tremblay, F. C. Szoka, F. E. Cohen, S. B. Prusiner, and M. R. Scott, J. Virol. 75:3453-3461, 2001), we investigated the inactivation of prions by sodium dodecyl sulfate (SDS) in weak acid. As judged by sensitivity to proteolytic digestion, the disease-causing prion protein (PrPSc) was denatured at room temperature by SDS at pH values of ≤4.5 or ≥10. Exposure of Sc237 prions in Syrian hamster brain homogenates to 1% SDS and 0.5% AcOH at room temperature resulted in a reduction of prion titer by a factor of ca. 107; however, all of the bioassay hamsters eventually developed prion disease. When various concentrations of SDS and AcOH were tested, the duration and temperature of exposure acted synergistically to inactivate both hamster Sc237 prions and human sporadic Creutzfeldt-Jakob disease (sCJD) prions. The inactivation of prions in brain homogenates and those bound to stainless steel wires was evaluated by using bioassays in transgenic mice. sCJD prions were more than 100,000 times more resistant to inactivation than Sc237 prions, demonstrating that inactivation procedures validated on rodent prions cannot be extrapolated to inactivation of human prions. Some procedures that significantly reduced prion titers in brain homogenates had a limited effect on prions bound to the surface of stainless steel wires. Using acidic SDS combined with autoclaving for 15 min, human sCJD prions bound to stainless steel wires were eliminated. Our findings form the basis for a noncorrosive system that is suitable for inactivating prions on surgical instruments, as well as on other medical and dental equipment.[/quote
So your trying to tell me that a plastic or rubber tube can be cleaned chute side and not cross contaminate. How does that work for the chain of custody you talk about?]
