Effective of different industrial disinfection in subzero cold-chain environment

Effective disinfection methods are crucial in the cold chain transportation process of food due to the specificity of temperature and the diversity of contaminated flora. The objective of this study was to investigate the sanitizing effect of different disinfectants on various fungi at - 20 °C to achieve accurate disinfection of diverse bacterial populations. Peracetic acid, hydrogen peroxide, and potassium bisulfate were selected as low-temperature disinfectants and were combined with antifreeze. The sanitizing effect of these cryogenic disinfectants on pathogens such as Bacillus subtilis black variant spores (ATCC9372), Staphylococcus aureus (ATCC 6538), Candida albicans (ATCC 10231), Escherichia coli (8099), and poliovirus (PV-1) was sequentially verified by bactericidal and virus inactivation experiments. After a specified time of disinfection, a neutralizing agent was used to halt the sanitizing process. The study demonstrates that different disinfectants exhibit selective effects during the low-temperature disinfection process. Peracetic acid, hydrogen peroxide, and potassium monopersulfate are suitable for the low-temperature environmental disinfection of bacterial propagules, viruses, and fungal contaminants. However, for microorganisms with strong resistance to spores, a low-temperature disinfectant based on peracetic acid should be chosen for effective disinfection treatment. Our results provide a valuable reference for selecting appropriate disinfectants to sanitize various potential pathogens in the future.

Efficiency of Virucidal Disinfectants on Wood Surfaces in Animal Husbandry

The aim of this study was to test the inactivation of viruses on germ carriers of different types of wood using a disinfectant in order to assess the biosafety of wood as a building material in animal husbandry. The laboratory disinfectant efficacy tests were based on German testing guidelines and current European standards. Five different types of wood germ carriers, i.e., spruce (Picea abies), pine (Pinus sylvestris), poplar (Populus sp.), beech (Fagus sylvatica) and Douglas fir (Pseudotsuga menziesii), were inoculated with enveloped or non-enveloped viruses and then treated with one of three different disinfectants. The results revealed that intact, fine-sawn timber with a low roughness depth can be effectively inactivated. Peracetic acid proved to be the most effective disinfectant across all tests. Regardless of the pathogen and the type of wood, a concentration of 0.1% of the pure substance at a temperature of 10 °C and an exposure time of one hour can be recommended. At a temperature of -10 °C, a concentration of 0.75% is recommended. The basic chemicals formic acid and glutaraldehyde demonstrated only limited effectiveness overall. The synergistic effects of various wood components on the inactivation of viruses offer potential for further investigation. Disinfectant tests should also be conclusively verified in field trials to ensure that the results from standardised laboratory tests can be transferred to real stable conditions.

Biocides in the Hospital Environment: Application and Tolerance Development

Hospital-acquired infections are a rising problem with consequences for patients, hospitals, and health care workers. Biocides can be employed to prevent these infections, contributing to eliminate or reduce microorganisms' concentrations at the hospital environment. These antimicrobials belong to several groups, each with distinct characteristics that need to be taken into account in their selection for specific applications. Moreover, their activity is influenced by many factors, such as compound concentration and the presence of organic matter. This article aims to review some of the chemical biocides available for hospital infection control, as well as the main factors that influence their efficacy and promote susceptibility decreases, with the purpose to contribute for reducing misusage and consequently for preventing the development of resistance to these antimicrobials.

Inactivation of Tulane virus and feline calicivirus by aqueous ozone

Ongoing challenges with reproducible human norovirus cultivable assays necessitate the use of surrogates, such as feline calicivirus (FCV-F9) and Tulane virus (TV), during inactivation studies. Chlorine alternates used as control strategies include aqueous and gaseous ozone. This study aimed at determining the inactivation of FCV-F9 and TV by a portable ozone-generating device. FCV-F9 (∼8 log PFU/mL) or TV (∼6 log PFU/mL) in sterile-low-organic matter-containing-water was treated for 0-5 min, or in sterile-water containing newborn calf serum (high-organic matter/protein) for 0-38 min with ∼1 ppm ozone (pH 7-6). Infectivity was determined from triplicate treatments using plaque assays. FCV-F9 titers significantly decreased by 6.07 log PFU/mL after 5 min in ozonated low-organic-matter-containing-water and was non-detectable (≤2 log PFU/mL) after 36 min treatments in high-organic-matter-containing water (p < 0.05). TV titers decreased by 4.18 log PFU/mL after 4 min in ozonated low-organic-matter water (non-detectable after 4.5 min) and were non-detectable after 22.5 min treatments of high-organic-matter-containing water (p < 0.05). Overall, ∼1 ppm aqueous ozone significantly decreased FCV-F9 by >6 log PFU/mL after 5 min, TV to non-detectable levels (≤2 log PFU/mL) after 4.5 min and required longer treatments (>32 and >20 min, respectively) for ≥4 log reduction in high-organic-matter-containing water (p < 0.05). For ozone treatment of both viruses, the linear and Weibull models were similar for low-organic-load water, though the Weibull model was better for the high-organic load water. Prior filtration or organic load removal is recommended before ozonation for increased viral inactivation with decreased treatment-time.

Surrogate Selection for Foot-and-Mouth Disease Virus in Disinfectant Efficacy Tests by Simultaneous Comparison of Bacteriophage MS2 and Bovine Enterovirus Type 1

In South Korea, testing disinfectants against foot-and-mouth disease virus (FMDV) that are contagious in livestock or that require special attention with respect to public hygiene can be manipulated only in high-level containment laboratories, which are not easily available. This causes difficulties in the approval procedure for disinfectants, such as a prolonged testing period. Additionally, the required biosafety level (BSL) in the case of FMDV has hindered its extensive studies. However, this drawback can be circumvented by using a surrogate virus to improve the performance of the efficacy testing procedure for disinfectants. Therefore, we studied bacteriophage MS2 (MS2) and bovine enterovirus type 1 (ECBO) with respect to disinfectant susceptibility for selecting a surrogate for FMDV according to the Animal and Plant Quarantine Agency (APQA) guidelines for efficacy testing of veterinary disinfectants. Effective concentrations of the active substances in disinfectants (potassium peroxymonosulfate, sodium dichloroisocyanurate, malic acid, citric acid, glutaraldehyde, and benzalkonium chloride) against FMDV, MS2, and ECBO were compared and, efficacies of eight APQA-listed commercial disinfectants used against FMDV were examined. The infectivity of FMDV and ECBO were confirmed by examination of cytopathic effects, and MS2 by plaque assay. The results reveal that the disinfectants are effective against MS2 and ECBO at higher concentrations than in FMDV, confirming their applicability as potential surrogates for FMDV in efficacy testing of veterinary disinfectants.

The efficacy of different sanitizers against MS2 bacteriophage introduced onto plastic or stainless steel surfaces

The virucidal activities of 11 prepared disinfectant solutions (active ingredients of household sanitizers) and 10 household sanitizers against bacteriophage MS2 on plastic and stainless steel surfaces were studied. Among the prepared sanitizers, 70-90% ethanol and ethanol-based disinfectants resulted in 1-2.5 log PFU/mL reductions on both surfaces. The 70% isopropanol and isopropanol-based formula reduced MS2 by 0.7-1.5 log PFU/mL on both surfaces. Other disinfectants, containing 0.1% benzalkonium chloride (BAC), 0.5% hydrogen peroxide, or 4% acetic acid, showed significant (P < 0.05) lower log reductions (-0.17-0.55 log PFU/mL) compared with other treatments. At room temperature, the virucidal activities of 70% ethanol on plastic (1.46-1.64 log PFU/mL reductions) and stainless steel (0.84-0.93 log PFU/mL reductions) surfaces were not significantly (P > 0.05) affected by the treatment time (30-600 s). However, 85% ethanol-treated groups showed significant (P < 0.05) higher log reductions in 60 and 600 s treated groups (1.69-2.24 log PFU/mL) compared with those in 30 s treated groups (0.92-1.32 log PFU/mL). Their virucidal activities were further examined at low temperatures (4 and 8 °C). We observed that the surface inactivation efficacies were not affected by the low temperatures. In addition, the virucidal activities of household sanitizers revealed that sanitizers with 1.84% (pH = 12.5, ∼17,500 ppm free-chlorine concentrations) or 3% (pH = 13.1, ∼38,100 ppm free-chlorine concentrations) sodium hypochlorite (NaClO) reduced 4.15-6.23 log PFU/mL MS2 on hard surfaces after 60 s contact time. Furthermore, an approximately 1.5 log PFU/mL reduction was observed in groups treated by sanitizer H (active ingredients: 58% ethanol + 0.1% quaternary ammonium compound). Household products with BAC or organic acid resulted in -0.28-0.33 log reductions on two surfaces after 30 or 60 s treatment. Therefore, the use of ethanol and NaClO-based products should be considered as a potential surface decontamination strategy in the food industry.

Comparison of virucidal efficacy of sodium hypochlorite, chlorine dioxide, peracetic acid, and ethanol against hepatitis A virus by carrier and suspension tests

A carrier (stainless steel disc as a default carrier) testing method is very needed for use in the actual food-processing fields by following the standard guideline. Here, we aimed to compare the virucidal efficacy of four commercial liquid disinfectants, including sodium hypochlorite (NaOCl), chlorine dioxide (ClO₂), and peracetic acid (PAA) against hepatitis A virus (HAV) following the OECD guideline protocol based on the quantitative carrier testing method and compared carrier testing results with the suspension testing results. The OECD method specifies a test for establishing whether a chemical disinfectant or a microbicide has a virucidal activity on hard non-porous surfaces. The antiviral efficacy was evaluated by plaque assays, and disinfectants were considered effective if the virus reduction was greater than or equal to 3 log₁₀ (99.9% decrease) for carrier or 4 log₁₀ (99.99% decrease) for suspension tests. Results indicated that ClO₂ above 500 ppm and 50% ethanol were effective in the carrier test method. In contrast, more than 200 ppm NaOCl and 50 ppm ClO₂ for all exposure times and 70% ethanol with contact for more than 5 min were effective in suspension tests. Treatment with PAA (80-2500 ppm) were not effective in carrier or suspension tests. Therefore, we recommend the use of more than 500 ppm ClO₂ or 50% ethanol with exposure for 10 min to disinfect surfaces that may be contaminated with HAV. Thus, these results could be effective in establishing official antiviral efficacy testing methods and basic data.

A systematic review of chlorine-based surface disinfection efficacy to inform recommendations for low-resource outbreak settings

Background

Infectious diseases can be transmitted via fomites (contaminated surfaces/objects); disinfection can interrupt this transmission route. However, disinfection guidelines for low-resource outbreak settings are inconsistent and not evidence-based.

Methods

A systematic review of surface disinfection efficacy studies was conducted to inform low-resource outbreak guideline development. Due to variation in experimental procedures, outcomes were synthesized in a narrative summary focusing on chlorine-based disinfection against 7 pathogens with potential to produce outbreaks in low-resource settings (Mycobacterium tuberculosis, Vibrio cholerae, Salmonella spp., hepatitis A virus, rotavirus, norovirus, and Ebola virus).

Results

Data were extracted from 89 laboratory studies and made available, including 20 studies on relevant pathogens used in combination with surrogate data to determine minimum target concentration × time (“CT”) factors. Stainless steel (68%) and chlorine-based disinfectants (56%) were most commonly tested. No consistent trend was seen in the influence of chlorine concentration and exposure time on disinfection efficacy. Disinfectant application mode; soil load; and surface type were frequently identified as influential factors in included studies.

Conclusions

This review highlights that surface disinfection efficacy estimates are strongly influenced by each study's experimental conditions. We therefore recommend laboratory testing to be followed by field-based testing/monitoring to ensure effectiveness is achieved in situ.

Concerns and strategies for wastewater treatment during COVID-19 pandemic to stop plausible transmission

Along with outbreak of the pandemic COVID-19 caused by SARS-CoV-2, the problem of biomedical wastewater disposal has caused widespread public concern, as reportedly the presence is confirmed in wastewater. Keeping in mind (i) available evidence indicating need to better understand potential of wastewater mediated transmission and (ii) knowledge gaps in its occurrence, viability, persistence, and inactivation in wastewater, in this present work, we wanted to re-emphasize some strategies for management of SARS-CoV-2 contaminated wastewater to minimise any possible secondary transmission to human and environment. The immediate challenges to consider while considering wastewater management are uncertainty about this new biothreat, relying on prediction based treatments options, significant population being the latent asymptomatic carrier increased risk of passing out of the virus to sewage network, inadequacy of wastewater treatment facility particularly in populated developing countries and increased generation of wastewater due to increased cleanliness concern. In absence of regulated central treatment facility, installation of decentralized wastewater treatment units with single or multiple disinfection barriers in medical units, quarantine centre, isolation wards, testing facilities seems to be urgent for minimizing any potential risk of wastewater transmission. Employing some emerging disinfectants (peracetic acid, performic acid, sodium dichloro isocyanurate, chloramines, chlorine dioxide, benzalconium chloride) shows prospects in terms of virucidal properties. However, there is need of additional research on coronaviruses specific disinfection data generation, regular monitoring of performance considering all factors influencing virus survival, performance evaluation in actual water treatment, need of augmenting disinfection dosages, environmental considerations to select the most appropriate disinfection technology.

Value-added switchgrass extractives for reduction of Escherichia coli O157:H7 and Salmonella Typhimurium populations on Formica coupons

Recurring outbreaks linked to Escherichia coli O157:H7-contaminated lettuce and Salmonella enterica-contaminated sprouts highlight the need for improved food safety measures. The aim of this study was to determine the ability of a bio-based antimicrobial extract prepared from switchgrass, a dedicated energy crop, to reduce E. coli O157:H7 and S. Typhimurium populations on Formica coupons, a model food-contact surface. Overnight cultures of ~7 log CFU/mL E. coli O157:H7 and S. Typhimurium, air-dried on Formica coupons were treated with 0.625% NaClO, 70% ethanol, sterile water or different batches of switchgrass extractives (SE1, SE2, and SE3) for up to 30 min. E. coli O157:H7 was reduced by 4.43 log CFU/mL after 1 min by SE3, and to non-detectable levels after 1 min by all other treatments. Populations of S. Typhimurium LT2 (15-min drying) were reduced by 3.30 log CFU/mL with 70% ethanol, 5.38 log CFU/mL with SE1, and to non-detectable levels with 0.625% NaClO after 1 min, while S. Typhimurium ATCC 23564 (1-h drying) was non-detectable after 1 min by all treatments. Under soiled conditions, 10-min treatment with SE1 and 70% ethanol reduced both bacteria to non-detectable levels. Studies with concentrated switchgrass extractives combined with various other natural disinfectants or in hurdle approaches warrant further investigation.

Antiphage activity of natural and synthetic substances: a new age for antivirals?

Viruses are considered biological entities that possess a genome and can adapt to the environment of living organisms. Since they are obligate intracellular parasites, their cycle of replication can result in cell death, and consequently, some viruses are harmful to mammalian cells and can cause disease in humans. Therefore, the search for substances for the treatment of viral diseases can be accomplished through the use of bacteriophages as models for eukaryotic cell viruses. Thus, this review highlights the main studies identifying substances with antiphage activity in comparison assays involving phages and eukaryotic viruses, in order to explore the potential of these substances as antivirals. As a future perspective, this approach may help at the beginning of an Antiviral Age.

Resistance to Antiseptics and Disinfectants of Planktonic and Biofilm-Associated Forms of Corynebacterium striatum

Disinfection and antisepsis are of primary importance in controlling nosocomial infections and outbreaks by pathogens expressing multiple resistance to antimicrobial agents (multidrug-resistant [MDR]) used in therapy. Nowadays, infections related to health services (HAIs) due to MDR and multidrug-susceptible (MDS) Corynebacterium striatum should not be underestimated, including patients using invasive medical devices. The virulence potential of C. striatum needs further investigation. Currently, susceptibility profiles of planktonic and/or sessile forms of four C. striatum strains of different pulsed-field gel electrophoresis types were examined as biocides based on the manufacturer's recommendations: 2% glutaraldehyde (GA), 2% peracetic acid (PA), 1% potassium monopersulfate (Virkon^®; VK), 1% sodium hypochlorite (SH), and 70% ethyl alcohol (ET). Time-kill assays using 2% bovine serum albumin (BSA) were performed for evaluation of influence of organic matter on biocides effects. Planktonic forms expressed GA resistance at different levels. C. striatum viability was observed until 2, 4, 20, and 30 min for MDR 2369/II, MDS 1954/IV, MDR 1987/I, and MDS 1961/III strains, respectively. In contrast to GA, the biocides PA, VK24h, SH, and ET had higher effective bacterial mortality. However, storage of VK (48 hr) reduced their biocide activities. Moreover, mature biofilms were produced on abiotic substrates, including steel surfaces. Post-treatment with GA (30 min), survival of sessile forms was ≥100% than planktonic forms of all C. striatum tested strains. Independent of biocides tested, BSA increased the survival of planktonic and sessile forms (p ≤ 0.005). Present data indicated that hospital staff should be aware of dissemination and eradication of HAIs by C. striatum presenting resistance to biocides, including high-level disinfectants, such as GA.

Combination of polyhexamethylene guanidine hydrochloride and potassium peroxymonosulfate to disinfect ready-to-eat lettuce

There is increasing demand for improved fresh produce disinfection technology during the ready-to-eat stage, especially in low-income developing countries. We previously reported that polyhexamethylene guanidine hydrochloride (PHMG) is an effective sanitizer using fresh-cut lettuce as a model. As a low-cost alternative, in the present study, we examined the disinfection efficacy of combining PHMG with the oxidizing sanitizer potassium peroxymonosulfate (PMS). PHMG (150 mg L⁻¹) reduced the counts of Escherichia coli O157:H7, non-O157 E. coli, Listeria monocytogenes, Salmonella typhimurium, and naturally present microbes on ready-to-eat lettuce. The disinfection efficacy of PMS was significantly lower than that of PHMG; however, the efficacy of their combination (100 mg L⁻¹ PHMG + 50 mg L⁻¹ PMS, 50 mg L⁻¹ PHMG + 100 mg L⁻¹ PMS, and 50 mg L⁻¹ PHMG + 50 mg L⁻¹ PMS) was equivalent to that of PHMG alone. Color and sensory analyses (crispness, color, flavour, and off-odor) indicated that the combination of PHMG and PMS will not lead to additional quality loss when compared with tap water treatment, and electrolyte leakage analysis showed no additional lettuce surface damage of the combination when compared with PHMG-only treatment. These results show that partial replacement of PHMG by PMS is a cost-reducing strategy, providing a theoretical foundation for its practical application.

Combination of polyhexamethylene guanidine hydrochloride and potassium peroxymonosulfate can achieve consistent disinfection effects as those obtained with polyhexamethylene guanidine hydrochloride but at a lower cost.

Persistence of Hepatitis A Virus in Fresh Produce and Production Environments, and the Effect of Disinfection Procedures: A Review

Although information is limited, it is evident that prolonged persistence of infectious Hepatitis A virus (HAV) is a factor in the transmission of the virus via fresh produce. Consequently, data on persistence of the virus on produce, and in environments relevant to production, such as soils, water and surfaces, are required to fully understand the dynamics of transmission of HAV via foods. Furthermore, information on effective disinfection procedures is necessary to implement effective post-harvest control measures. This review summarises current information on HAV persistence in fresh produce and on relevant disinfection procedures. On vegetables, HAV can remain infectious for several days; on frozen berries, it can persist for several months. HAV can remain infectious on surfaces for months, depending on temperature and relative humidity, and can survive desiccation. It can survive for several hours on hands. Washing hands can remove the virus, but further data are required on the appropriate procedure. Chlorination is effective in water, but not when HAV is associated with foodstuffs. Bleach and other sodium hypochlorite disinfectants at high concentrations can reduce HAV on surfaces, but are not suitable for use on fresh produce. There is only limited information on the effects of heating regimes used in the food industry on HAV. HAV is resistant to mild pasteurisation. Some food components, e.g. fats and sugars, can increase the virus' resistance to higher temperatures. HAV is completely eliminated by boiling. Quantitative prevalence data are needed to allow the setting of appropriate disinfection log reduction targets for fresh produce.

Virucides in apiculture: persistence of surrogate enterovirus under simulated field conditions

BACKGROUND

Honeybee viruses have been recognized as being among the most important factors leading to colony losses worldwide. Colony food and faeces are regarded as possible sources of infectious viruses able to contaminate the environment and equipment of apiaries. Thus, methods for elimination of viruses are required. No cell culture assay for testing the effect of disinfectants on honeybee viruses is yet available. Therefore, surrogate virus was employed for testing of the efficacy of iodophor- and peracetic acid-based disinfectants in combination with six organic contaminants at +6 °C and +22 °C. Moreover, we evaluated the persistence of the surrogate in honey at +6 °C, +22 °C, and +50 °C.

RESULTS

Iodophor-based disinfectant showed a maximum reduction of virus titre of 3.4 log₁₀ . Peracetic acid reduced the titre (≥4 log₁₀ ) only at 22 °C and without yeast extract/bovine serum albumin. After 25 days of incubation of the virus - honey mix, no decrease of virus titre was observed at +6 °C, whereas a significant reduction (3.5 log₁₀ ) was found at +50 °C already after 1 day.

CONCLUSIONS

Both tested disinfectants can serve as appropriate virucides in apiaries. The effect of peracetic acid significantly depended on temperature and organic contaminants. The iodophor-based disinfectant showed a stable antiviral effect at different temperatures and with different contaminants. © 2017 Society of Chemical Industry.