Efficacy of humidity retention bags for the reduced adsorption and improved cleaning of tissue proteins including prion-associated amyloid to surgical stainless steel surfaces

Increasing drying time adversely affects attachment of tissue proteins and prion-associated amyloid to surgical stainless steel, and reduces the efficacy of commercial cleaning chemistries. This study tested the efficacy of commercial humidity retention bags to reduce biofouling on surgical stainless steel and to improve subsequent cleaning. Surgical stainless steel surfaces were contaminated with ME7-infected brain homogenates and left to dry for 15 to 1,440 min either in air, in dry polythene bags or within humidity retention bags. Residual contamination pre/post cleaning was analysed using Thioflavin T/SYPRO Ruby dual staining and microscope analysis. An increase in biofouling was observed with increased drying time in air or in sealed dry bags. Humidity retention bags kept both protein and prion-associated amyloid minimal across the drying times both pre- and post-cleaning. Therefore, humidity bags demonstrate a cheap, easy to implement solution to improve surgical instrument reprocessing and to potentially reduce associated hospital acquired infections.     

Homogenous photocatalytic decontamination of prion infected stainless steel and titanium surfaces

Prions are notorious for their extraordinary resistance to traditional methods of decontamination, rendering their transmission a public health risk. Iatrogenic Creutzfeldt–Jakob disease (iCJD) via contaminated surgical instruments and medical devices has been verified both experimentally and clinically. Standard methods for prion inactivation by sodium hydroxide or sodium hypochlorite have failed, in some cases, to fully remove prion infectivity, while they are often impractical for routine applications. Prion accumulation in peripheral tissues and indications of human-to-human bloodborne prion transmission, highlight the need for novel, efficient, yet user-friendly methods of prion inactivation. Here we show both in vitro and in vivo that homogenous photocatalytic oxidation, mediated by the photo-Fenton reagent, has the potential to inactivate the pathological prion isoform adsorbed on metal substrates. Photocatalytic oxidation with 224 μg mL⁻¹ Fe³⁺, 500 μg mL⁻¹ h⁻¹ H₂O₂, UV-A for 480 min lead to 100% survival in golden Syrian hamsters after intracranial implantation of stainless steel wires infected with the 263K prion strain. Interestingly, photocatalytic treatment of 263K infected titanium wires, under the same experimental conditions, prolonged the survival interval significantly, but failed to eliminate infectivity, a result that we correlate with the increased adsorption of PrP^Sc on titanium, in comparison to stainless steel. Our findings strongly indicate that our, user- and environmentally friendly protocol can be safely applied to the decontamination of prion infected stainless steel surfaces.     

Corrosion protection of reusable surgical instruments

To understand the corrosion properties of surgical scissors, 416 stainless steel disks and custom electrodes were used as simulated surfaces under various conditions. These simulated surfaces were exposed to tap water and 400-ppm synthetic hard water as Ca2CO3 under different conditions. The samples were evaluated by various techniques for corrosion potential and the impact of environmental conditions on the integrity of the passive film. The electrodes were used to monitor the corrosion behavior by potentiodynamic polarization technique in water both in the presence and absence of a cleaning product. The surface topography of the 416 stainless steel disks was characterized by visual observations and scanning electron microscopy (SEM), and the surface chemistry of the passive film on the surface of the scissors was characterized by x-ray photoelectron spectroscopy (XPS). The results suggest that surgical instruments made from 416 stainless steel are not susceptible to uniform corrosion; however, they do undergo localized corrosion. The use of suitable cleaning products can offer protection against localized corrosion during the cleaning step. More importantly, the use of potentiodynamic polarization techniques allowed for a quick and convenient approach to evaluate the corrosion properties of surgical instruments under a variety of simulated-use environmental conditions.     

Investigations of a prion infectivity assay to evaluate methods of decontamination

Prions are unique infectious agents which have been shown to be transmitted iatrogenically through contaminated surfaces. Surface contamination is a concern on reusable medical devices and various industrial surfaces, but there is currently no standard, accepted model to evaluate surface prion decontamination. In this report, a set of both in vitro and in vivo methods were investigated based on the contamination of surface through artificial exposure to infected brain. An in vitro surface contamination protocol was developed with subsequent biochemical detection of the prion protein (PrPres). In parallel, the in vivo investigations included the contamination of different types of surface materials (stainless steel or plastic wires) with different prion strains (scrapie strain adapted to hamsters 263K or bovine spongiform encephalopathy strain adapted to mouse 6PB1). The in vivo models with various prion strains and brain homogenate dilutions reproducibly transmitted the disease and a relationship was established between the infectivity titre, the transmission rate and the incubation period. Moreover, the in vivo models were studied for their ability to demonstrate the efficacy of heat and chemical-based decontamination methods, with similar results. The in vivo scrapie method described is proposed as a standard to evaluate existing and developing prion decontamination technologies.     

Rapid and Highly Sensitive Detection of Variant Creutzfeldt - Jakob Disease Abnormal Prion Protein on Steel Surfaces by Protein Misfolding Cyclic Amplification: Application to Prion Decontamination Studies

The prevalence of variant Creutzfeldt-Jakob disease (vCJD) in the population remains uncertain, although it has been estimated that 1 in 2000 people in the United Kingdom are positive for abnormal prion protein (PrP^TSE) by a recent survey of archived appendix tissues. The prominent lymphotropism of vCJD prions raises the possibility that some surgical procedures may be at risk of iatrogenic vCJD transmission in healthcare facilities. It is therefore vital that decontamination procedures applied to medical devices before their reprocessing are thoroughly validated. A current limitation is the lack of a rapid model permissive to human prions. Here, we developed a prion detection assay based on protein misfolding cyclic amplification (PMCA) technology combined with stainless-steel wire surfaces as carriers of prions (Surf-PMCA). This assay allowed the specific detection of minute quantities (10⁻⁸ brain dilution) of either human vCJD or ovine scrapie PrP^TSE adsorbed onto a single steel wire, within a two week timeframe. Using Surf-PMCA we evaluated the performance of several reference and commercially available prion-specific decontamination procedures. Surprisingly, we found the efficiency of several marketed reagents to remove human vCJD PrP^TSE was lower than expected. Overall, our results demonstrate that Surf-PMCA can be used as a rapid and ultrasensitive assay for the detection of human vCJD PrP^TSE adsorbed onto a metallic surface, therefore facilitating the development and validation of decontamination procedures against human prions.     

The survival and transfer of microbial contamination via cloths, hands and utensils

Survival and transfer of bacteria from laminated surfaces and cleaning cloths were investigated under laboratory conditions. Drying produced substantial reductions in numbers of recoverable organisms and achieved satisfactory decontamination of clean laminate surfaces. On soiled surfaces and on clean and soiled cloths, Gram-positive and some Gram-negative species survived for up to 4 h, and in some cases up to 24 h. Where contaminated surfaces or cloths came into contact with the fingers, a stainless steel bowl, or a clean laminate surface, organisms were transferred in sufficient numbers to represent a potential hazard if in contact with food.     

The survival and transfer of microbial contamination via cloths, hands and utensils

Survival and transfer of bacteria from laminated surfaces and cleaning cloths were investigated under laboratory conditions. Drying produced substantial reductions in numbers of recoverable organisms and achieved satisfactory decontamination of clean laminate surfaces. On soiled surfaces and on clean and soiled cloths, Gram-positive and some Gram-negative species survived for up to 4 h, and in some cases up to 24 h. Where contaminated surfaces or cloths came into contact with the fingers, a stainless steel bowl, or a clean laminate surface, organisms were transferred in sufficient numbers to represent a potential hazard if in contact with food.     

Cleanability in relation to bacterial retention on unused and abraded domestic sink materials

The relative cleanability of stainless steel, enamelled steel, mineral resin and polycarbonate domestic sink materials was assessed by comparing the number of organisms remaining on surfaces after cleaning. In unused condition all materials, other than one enamelled steel, were equally cleanable. Stainless steel, abraded artificially or impact damaged to a similar degree as stainless steel subjected to domestic wear, retained approximately one log order less bacteria after cleaning than the other materials subjected to the same treatments. Little difference in cleanability was recorded between the abraded surfaces of the other materials although enamelled steel surfaces were less cleanable than mineral resin or polycarbonate after impact damage, because of the greater susceptibility of enamelled steel to damage by this treatment. When cleaning time was extended beyond 10 s for the abraded and impact damaged materials, their cleanability was not enhanced as compared with stainless steel. Changes in surface finish after abrasion were assessed by surface roughness measurement and scanning electron microscopy. Surfaces with poor cleanability before and after abrasion were characterized by pitting, crevices or jags. These surfaces are likely to retain more bacteria because of increased numbers of attachment sites, a larger bacterial/material surface contact area and topographical areas in which applied cleaning shear forces are reduced. Materials that resist surface changes, e.g. stainless steel, will remain more hygienic when subjected to natural wear than materials which become more readily damaged.     

Cleanability in relation to bacterial retention on unused and abraded domestic sink materials

H olah , J.T. & T horpe , R.H. 1990. Cleanability in relation to bacterial retention on unused and abraded domestic sink materials. Journal of Applied Bacteriology 69 , 599–608.
The relative Cleanability of stainless steel, enamelled steel, mineral resin and polycarbonate domestic sink materials was assessed by comparing the number of organisms remaining on surfaces after cleaning. In unused condition all materials, other than one enamelled steel, were equally cleanable. Stainless steel, abraded artificially or impact damaged to a similar degree as stainless steel subjected to domestic wear, retained approximately one log order less bacteria after cleaning than the other materials subjected to the same treatments. Little difference in Cleanability was recorded between the abraded surfaces of the other materials although enamelled steel surfaces were less cleanable than mineral resin or polycarbonate after impact damage, because of the greater susceptibility of enamelled steel to damage by this treatment. When cleaning time was extended beyond 10 s for the abraded and impact damaged materials, their Cleanability was not enhanced as compared with stainless steel. Changes in surface finish after abrasion were assessed by surface roughness measurement and scanning electron microscopy. Surfaces with poor Cleanability before and after abrasion were characterized by pitting, crevices or jags. These surfaces are likely to retain more bacteria because of increased numbers of attachment sites, a larger bacterial/material surface contact area and topographical areas in which applied cleaning shear forces are reduced. Materials that resist surface changes, e.g. stainless steel, will remain more hygienic when subjected to natural wear than materials which become more readily damaged.     

Adhesion of food-borne bacteria to stainless steel is reduced by food conditioning films

Aims:  Preconditioning of stainless steel with aqueous cod muscle extract significantly impedes subsequent bacterial adhesion most likely due to repelling effects of fish tropomyosin. The purpose of this study was to determine if other food conditioning films decrease or enhance bacterial adhesion to stainless steel.
Methods and Results:  Attachment of Pseudomonas fluorescens AH2 to stainless steel coated with water-soluble coatings of animal origin was significantly reduced as compared with noncoated stainless steel or stainless steel coated with laboratory substrate or extracts of plant origin. Coating with animal extracts also decreases adhesion of other food-relevant bacteria. The manipulation of adhesion was not attributable to growth inhibitory effects. Chemical analysis revealed that the stainless steels were covered by homogenous layers of adsorbed proteins. The presence of tropomyocin was indicated by appearance of proteins with similar molecular weight based in sodium dodecyl sulfate–polyacrylamide gel electrophoresis, in several extracts that reduced adhesion but also extracts not containing this protein reduced bacterial adhesion, indicating that several molecular species may be involved in the phenomenon.
Conclusions:  It is a common perception that food materials facilitate bacterial adhesion to surfaces; however, this study demonstrates that aqueous coatings of food origin may actually reduce bacterial adhesion.
Significance and Impact of the Study:  Compounds from food extracts may potentially be used as nontoxic coatings to reduce bacterial attachment to inert surfaces.     

Harnessing prions as test agents for the development of broad-range disinfectants

The development of disinfectants with broad-range efficacy against bacteria, viruses, fungi, protozoa and prions constitutes an ongoing challenge. Prions, the causative agents of transmissible spongiform encephalopathies (TSEs) such as Creutzfeldt-Jakob disease (CJD) or its variant (vCJD) rank among the pathogens with the highest resistance to disinfection. Pilot studies have shown that different procedures devised for prion disinfection were also highly effective against microbial pathogens. This fueled the idea to systematically exploit prions as test pathogens for the identification of new potential broad-range disinfectants. Prions essentially consist of misfolded, aggregated prion protein (PrP) and putatively replicate by nucleation-dependent, or seeded PrP polymerization. Recently, we have been able to establish PrP seeding activity as a quantitative in vitro indicator for the disinfection of 263K scrapie prions on steel wires used as surrogates for medical instruments. The seeding activity on wires re-processed in different disinfectants could be (1) biochemically determined by quantitative protein misfolding cyclic amplification (qPMCA), (2) biologically detected after qPMCA in a cell assay and (3) correctly translated into residual titers of scrapie infectivity. Our approach will substantially facilitate the identification of disinfectants with efficacy against prions as promising candidates for a further microbiological validation of broad-range activity.Key words: cell assay, disinfection, prion, prion protein, protein misfolding cyclic amplification, scrapie, seeding activity, surgical instruments, transmissible spongiform encephalopathies     

On-chip identification and interaction analysis of gel-resolved proteins using a diamond-like carbon-coated plate

We developed a novel protein chip made of a diamond-like, carbon-coated stainless steel plate (DLC plate), the surface of which is chemically modified with N-hydroxysuccinimide ester. To produce a high-density protein chip using the DLC plate, proteins separated by SDS gel electrophoresis or two-dimensional electrophoresis were electroblotted onto the DLC plate and immobilized covalently. A high blotting efficiency (25-70%) for transferring proteins from the gels onto the DLC plates was achieved by improvement of the electrophoresis device and electroblotting techniques. With the use of the DLC plate, we developed novel techniques to identify proteins immobilized on the chip and to detect protein-protein interactions on the chip by mass spectrometric analysis. We also developed a technique to identify post-translationally modified proteins, such as glycoproteins, on the protein chip.     

Rapid reduction of Legionella pneumophila on stainless steel with zeolite coatings containing silver and zinc ions

AIMS: To determine the rate of reduction of Legionella pneumophila by stainless steel surfaces with zeolite ceramic coatings containing 2.5% (w/w) silver (Ag) and 14% zinc (Zn) ions. METHODS AND RESULTS: Stainless steel pans with and without Ag/Zn coatings were inoculated with solutions of Leg. pneumophila ATCC 33155 and incubated at 37 degrees C. Survival was monitored using the spread-plate technique on selective buffered charcoal yeast extract agar. Significant reductions of Leg. pneumophila were effected by the Ag/Zn zeolite coatings within 2 h of exposure. CONCLUSIONS, Significance and Impact of the Study: Zeolite ceramic Ag/Zn coatings impart significant anti-Legionella properties to stainless steel surfaces. Coated stainless steel could be used in the manufacture of air ducts, condensation pans and intake and exhaust vents. These products have the potential to reduce numbers of Legionella in air-handling systems.     

Adhesion and removal kinetics of Bacillus cereus biofilms on Ni-PTFE modified stainless steel

Biofilm control remains a challenge to food safety. A well-studied non-fouling coating involves codeposition of polytetrafluoroethylene (PTFE) during electroless plating. This coating has been reported to reduce foulant build-up during pasteurization, but opportunities remain in demonstrating its efficacy in inhibiting biofilm formation. Herein, the initial adhesion, biofilm formation, and removal kinetics of Bacillus cereus on Ni-PTFE-modified stainless steel (SS) are characterized. Coatings lowered the surface energy of SS and reduced biofilm formation by > 2 log CFU cm^?2. Characterization of the kinetics of biofilm removal during cleaning demonstrated improved cleanability on the Ni-PTFE coated steel. There was no evidence of biofilm after cleaning by either solution on the Ni-PTFE coated steel, whereas more than 3 log and 1 log CFU cm^?2 of bacteria remained on the native steel after cleaning with water and an alkaline cleaner, respectively. This work demonstrates the potential application of Ni-PTFE non-fouling coatings on SS to improve food safety by reducing biofilm formation and improving the cleaning efficiency of food processing equipment.     

On-line monitoring of antifouling and fouling-release surfaces using bioluminescence and fluorescence measurements during laminar flow

A laminar flow biofilm-monitoring system was used to determine the efficacies of three antifouling (AF) coatings and five fouling-release (FR) coatings againstVibrio harveyi attachment. On-line measurements of tryptophan fluorescence and bioluminescence from each coating, normalized to an upstream stainless steel coupon, were used to determine the effects of AF and FR surfaces on biofilm formation. The AF coatings consisted of 5, 10, and 35 wt% Sea Nine 211 (C9211) incorporated into a vinyl copolymer. Both the 10 and 35 wt% coatings significantly inhibited biofilm biomass development measured by tryptophan fluorescence compared to the stainless steel control.V. harveyi bioluminescence was significantly greater than tryptophan fluorescence in cells attached to these coatings, suggesting that bioluminescence expression may be a marker for cellular stress or toxicity in biofilms. Five different polydimethylsiloxane (PDMS) FR coatings did not inhibit biofilm formation under low flow conditions. However, four PDMS coatings demonstrated decreased biomass levels compared to stainless steel after exposure to a shear stress of 330 dynes cm^–2. There was no toxic additive in these coatings; bioluminescence and tryptophan fluorescence were proportional.     

Factors influencing attachment of thermophilic bacilli to stainless steel

AIMS: This project aimed to investigate the mechanism of attachment of the vegetative cells and spores of thermophilic bacilli to stainless steel with a view to devising strategies to limit biofilm development and survival. METHODS AND RESULTS: Spores and vegetative cells of bacterial isolates were exposed to protein denaturing agents (sodium dodecyl sulphate (SDS) and trypsin) and polysaccharide removing agents (sodium metaperiodate, trichloroacetic acid (TCA) and lysozyme). Treatment with sodium metaperiodate, TCA and lysozyme increased the number of vegetative cells attaching in many of the strains studied, while SDS and trypsin decreased attachment. Spores attached to stainless steel in greater numbers than vegetative cells, and the various treatments had less effect on this attachment than for vegetative cells. Viability of the cells or spores was not an important factor in attachment, as cells and spores rendered non-viable also attached to stainless steel in similar numbers. Coating the stainless steel with skim milk proteins decreased the attachment of both vegetative cells and spores. There was no correlation between the degree of attachment and the amount of extracellular polysaccharide (EPS) produced by each strain, surface hydrophobicity or zeta potential of vegetative cells or spores, though spores were found to be more hydrophobic than vegetative cells. CONCLUSIONS: The results suggest that biofilm formation by these thermophilic bacilli is probably a multifactorial process, and that cell-surface proteins play a very important role in the initial process of attachment during the formation of biofilms by these bacteria. SIGNIFICANCE AND IMPACT OF THE STUDY: This information will provide direction for developing improved cleaning systems to control biofilms of thermophilic bacilli in dairy manufacturing plants.     

电解海水的抑菌活性及对食品加工表面材料的消毒效果

为了考察直接电解海水消除细菌污染的可能性,本文将海水及海水稀释成不同浓度后通过氧化电解水装置进行电解不同时间后,所得酸性电解海水、碱性电解海水和中性电解海水对病原菌[埃希氏大肠杆菌(Escherichina coli)、沙门氏菌(Salmonella)、单核细胞增生李斯特菌(Listeria moncytogene)、摩化摩根(Morganella morganii)、副溶血性弧菌(Vibrio parahaemolyticus)]以及食品加工表面接触材料(地板砖、不锈钢板、瓷砖、手套、抹布)的消毒效果进行分析研究.结果表明,酸性电解海水具有良好的杀菌效果,能将107 CFU/mL的病原菌悬液在1 min内几乎全部杀死.碱性电解海水和中性水无明显的杀菌效果.通过模拟食品加工过程,对食品加工表面接触材料人为染菌,研究电解海水对表面材料的消毒效果,结果表明酸性电解海水仍能将表面材料含有的107CFU/cm2病原菌在5 min之内几乎全部杀灭.由此说明电解海水对食品加工表面接触材料具有明显的消毒效果,能取代以淡水为原料的电解水杀菌效果是高效廉价和不浪费淡水资源的一种理想消毒剂.     

Quantitative detection and biological propagation of scrapie seeding activity in vitro facilitate use of prions as model pathogens for disinfection

Prions are pathogens with an unusually high tolerance to inactivation and constitute a complex challenge to the re-processing of surgical instruments. On the other hand, however, they provide an informative paradigm which has been exploited successfully for the development of novel broad-range disinfectants simultaneously active also against bacteria, viruses and fungi. Here we report on the development of a methodological platform that further facilitates the use of scrapie prions as model pathogens for disinfection. We used specifically adapted serial protein misfolding cyclic amplification (PMCA) for the quantitative detection, on steel wires providing model carriers for decontamination, of 263K scrapie seeding activity converting normal protease-sensitive into abnormal protease-resistant prion protein. Reference steel wires carrying defined amounts of scrapie infectivity were used for assay calibration, while scrapie-contaminated test steel wires were subjected to fifteen different procedures for disinfection that yielded scrapie titre reductions of ≤10(1)- to ≥10(5.5)-fold. As confirmed by titration in hamsters the residual scrapie infectivity on test wires could be reliably deduced for all examined disinfection procedures, from our quantitative seeding activity assay. Furthermore, we found that scrapie seeding activity present in 263K hamster brain homogenate or multiplied by PMCA of scrapie-contaminated steel wires both triggered accumulation of protease-resistant prion protein and was further propagated in a novel cell assay for 263K scrapie prions, i.e., cerebral glial cell cultures from hamsters. The findings from our PMCA- and glial cell culture assays revealed scrapie seeding activity as a biochemically and biologically replicative principle in vitro, with the former being quantitatively linked to prion infectivity detected on steel wires in vivo. When combined, our in vitro assays provide an alternative to titrations of biological scrapie infectivity in animals that substantially facilitates the use of prions as potentially highly indicative test agents in the search for novel broad-range disinfectants.     

Role of curli fimbriae in mediating the cells of enterohaemorrhagic Escherichia coli to attach to abiotic surfaces

AIMS: The objectives of this study were to evaluate the role of curli in assisting the cells of enterohaemorrhagic Escherichia coli (EHEC) in attaching to abiotic surfaces and to determine the influence of cell-surface contact time on the efficiency of the attachment. METHODS AND RESULTS: Three pairs of EHEC cultures, each with a curli-expressing and a noncurli-expressing variant (O111:H- 7-57C+ and O157:H7 5-9C-, O157:H7 5-11C+ and 5-11C-, as well as O103:H2 7-52C+ and 7-52C-), were allowed to interact with polystyrene, glass, stainless steel and rubber surfaces at 28 degrees C for 24 h (short-term attachment) or 7 days (long-term attachment). The quantities of the cells that attached to the surfaces were measured daily in the long-term attachment study, and in 4 h intervals in the short-term attachment study. Quantification of the cells that attached to the surfaces was accomplished with a crystal violet binding assay. The results of the long-term attachment study indicated that 7-57C+ attached to the polystyrene and glass surfaces more efficiently (P < 0.05) than did 5-9C-. The curli-expressing variant of 5-11 possessed a better ability to adhere to the polystyrene and glass surfaces than did its noncurli-expressing counterpart (P < 0.05). The differences in attachment between 7-52C+ and 7-52C- on polystyrene and stainless steel surfaces were statistically significant (P < 0.05). However, the attachment of the pair on the glass surfaces was statistically insignificant (P > 0.05). In addition, the two members of all three EHEC pairs attached equally well to rubber surfaces (P > 0.05). In the short-term attachment study, only the pair of 7-52 attached differently on glass and stainless steel surfaces (P < 0.05). CONCLUSIONS: These results suggest that curli could be an important cell surface component to mediate the attachment of some EHEC cells to certain abiotic surfaces. Cell-surface contact time could have a significant influence on EHEC attachment to abiotic surfaces. SIGNIFICANCE AND IMPACT OF THE STUDY: The study signifies a possible role of curli in assisting the cells of EHEC in attaching to food-contact surfaces. It underlines the importance of cleaning and sanitizing food-contact surfaces regularly and thoroughly, and of identifying chemical agents that can effectively remove the attached EHEC cells from these surfaces.     

Inactivation of Prions and Amyloid Seeds with Hypochlorous Acid

Hypochlorous acid (HOCl) is produced naturally by neutrophils and other cells to kill conventional microbes in vivo. Synthetic preparations containing HOCl can also be effective as microbial disinfectants. Here we have tested whether HOCl can also inactivate prions and other self-propagating protein amyloid seeds. Prions are deadly pathogens that are notoriously difficult to inactivate, and standard microbial disinfection protocols are often inadequate. Recommended treatments for prion decontamination include strongly basic (pH ≥~12) sodium hypochlorite bleach, ≥1 N sodium hydroxide, and/or prolonged autoclaving. These treatments are damaging and/or unsuitable for many clinical, agricultural and environmental applications. We have tested the anti-prion activity of a weakly acidic aqueous formulation of HOCl (BrioHOCl) that poses no apparent hazard to either users or many surfaces. For example, BrioHOCl can be applied directly to skin and mucous membranes and has been aerosolized to treat entire rooms without apparent deleterious effects. Here, we demonstrate that immersion in BrioHOCl can inactivate not only a range of target microbes, including spores of Bacillus subtilis, but also prions in tissue suspensions and on stainless steel. Real-time quaking-induced conversion (RT-QuIC) assays showed that BrioHOCl treatments eliminated all detectable prion seeding activity of human Creutzfeldt-Jakob disease, bovine spongiform encephalopathy, cervine chronic wasting disease, sheep scrapie and hamster scrapie; these findings indicated reductions of ≥10³- to 10⁶-fold. Transgenic mouse bioassays showed that all detectable hamster-adapted scrapie infectivity in brain homogenates or on steel wires was eliminated, representing reductions of ≥~10^5.75-fold and >10⁴-fold, respectively. Inactivation of RT-QuIC seeding activity correlated with free chlorine concentration and higher order aggregation or destruction of proteins generally, including prion protein. BrioHOCl treatments had similar effects on amyloids composed of human α-synuclein and a fragment of human tau. These results indicate that HOCl can block the self-propagating activity of prions and other amyloids.