title: Quantitative analysis of wet-heat inactivation in bovine spongiform encephalopathy.
abstract: The bovine spongiform encephalopathy (BSE) agent is resistant to conventional microbial inactivation procedures and thus threatens the safety of cattle products and by-products. To obtain information necessary to assess BSE inactivation, we performed quantitative analysis of wet-heat inactivation of infectivity in BSE-infected cattle spinal cords. Using a highly sensitive bioassay, we found that infectivity in BSE cattle macerates fell with increase in temperatures from 133°C to 150°C and was not detected in the samples subjected to temperatures above 155°C. In dry cattle tissues, infectivity was detected even at 170°C. Thus, BSE infectivity reduces with increase in wet-heat temperatures but is less affected when tissues are dehydrated prior to the wet-heat treatment. The results of the quantitative protein misfolding cyclic amplification assay also demonstrated that the level of the protease-resistant prion protein fell below the bioassay detection limit by wet-heat at 155°C and higher and could help assess BSE inactivation. Our results show that BSE infectivity is strongly resistant to wet-heat inactivation and that it is necessary to pay attention to BSE decontamination in recycled cattle by-products.
authors: Prion Disease Research Center, National Institute of Animal Health, 3-1-5 Kannondai, Tsukuba, Ibaraki 305-0856, Japan.
authors: Yuichi
authors: Y
authors: Matsuura
authors: Yukiko
authors: Y
authors: Ishikawa
authors: Xiao
authors: X
authors: Bo
authors: Yuichi
authors: Y
authors: Murayama
authors: Takashi
authors: T
authors: Yokoyama
authors: Robert A
authors: RA
authors: Somerville
authors: Tetsuyuki
authors: T
authors: Kitamoto
authors: Shirou
authors: S
authors: Mohri
mesh_terms: D000818:Animals; D001681:Biological Assay; D002417:Cattle; D016643:Encephalopathy, Bovine Spongiform / Q000635:transmission*; D006358:Hot Temperature; D051379:Mice; D008822:Mice, Transgenic; D018620:PrPSc Proteins / Q000037:antagonists & inhibitors* / Q000737:chemistry*; D017510:Protein Folding; D013116:Spinal Cord
chemical_list: D018620:PrPSc Proteins