Avoid Cross Contamination Research Articles

Automated solid phase DNA extraction on a lab-on-a-disc with two-degrees of freedom instrumentation

BackgroundLab-on-a-disc (LoaD) technology has emerged as a transformative approach for point-of-care diagnostics and high-throughput testing. The promise of integrating multiple laboratory functions onto a single integrated platform has significant implications for healthcare, especially in resource-limited settings. However, one of the primary challenges faced in the design and manufacture of LoaD devices is the integration of effective valving mechanisms. These valves are essential for fluid control and routing, but their intricacy often leads to complexities in design and increased vulnerability to failure. This emphasizes the need for improved designs and manufacturing processes without complex, integrated valving mechanisms. (96) ResultsWe describe a fully automated biological workflow and reagent actuation on a LoaD device without an integrated valving system. The Two Degrees-of-Freedom (2DoF) custom centrifuge alters the centre of rotation, facilitating fluid flow direction changes on the microfluidic platform through a custom programmed interface. A novel 360-degree fluid manipulation approach via secondary planetary gear motion enabled sequential assay reagent actuation without embedded valve triggering, with the addition of infinite incubation times and efficient use of platform realty. The simplified LoaD platform uses clever design, with intermediate flow chambers to avoid cross contamination between reagent steps. Notably, the optimized LoaD platform demonstrated a two-fold DNA yield at higher HEK-293 cell concentrations compared to commercially available spin-column kits. This significantly simplified LoaD platform successfully automated a common, complex workflow without inhibiting DNA purification. (129) SignificanceThis system exhibits the clever coupling of both 2DoF and centrifugal microfluidics to create an autonomous testing package capable of eradicating the need for complex valving systems to automate biological workflows on LoaDs. This automated system has outperformed commercially available DNA extraction kits for higher cell counts. The platform's elimination of valve requirements ensures unlimited sample incubation times and enhances reliability, making it a straightforward option for automated biological workflows, particularly in diagnostics. (73)

Carryover Contamination-Controlled Amplicon Sequencing Workflow for Accurate Qualitative and Quantitative Detection of Pathogens: a Case Study on SARS-CoV-2.

Carryover contamination during amplicon sequencing workflow (AMP-Seq) put the accuracy of the high-throughput detection for pathogens at risk. The purpose of this study is to develop a carryover contaminations-controlled AMP-Seq (ccAMP-Seq) workflow to enable accurate qualitative and quantitative detection for pathogens. By using the AMP-Seq workflow to detect SARS-CoV-2, Aerosols, reagents and pipettes were identified as potential sources of contaminations and ccAMP-Seq was then developed. ccAMP-Seq used filter tips and physically isolation of experimental steps to avoid cross contamination, synthetic DNA spike-ins to compete with contaminations and quantify SARS-CoV-2, dUTP/uracil DNA glycosylase system to digest the carryover contaminations, and a new data analysis procedure to remove the sequencing reads from contaminations. Compared to AMP-Seq, the contamination level of ccAMP-Seq was at least 22-folds lower and the detection limit was also about an order of magnitude lower-as low as one copy/reaction. By testing the dilution series of SARS-CoV-2 nucleic acid standard, ccAMP-Seq showed 100% sensitivity and specificity. The high sensitivity of ccAMP-Seq was further confirmed by the detection of SARS-CoV-2 from 62 clinical samples. The consistency between qPCR and ccAMP-Seq was 100% for all the 53 qPCR-positive clinical samples. Seven qPCR-negative clinical samples were found to be positive by ccAMP-Seq, which was confirmed by extra qPCR tests on subsequent samples from the same patients. This study presents a carryover contamination-controlled, accurate qualitative and quantitative amplicon sequencing workflow that addresses the critical problem of pathogen detection for infectious diseases. IMPORTANCE Accuracy, a key indicator of pathogen detection technology, is compromised by carryover contamination in the amplicon sequencing workflow. Taking the detection of SARS-CoV-2 as case, this study presents a new carryover contamination-controlled amplicon sequencing workflow. The new workflow significantly reduces the degree of contamination in the workflow, thereby significantly improving the accuracy and sensitivity of the SARS-CoV-2 detection and empowering the ability of quantitative detection. More importantly, the use of the new workflow is simple and economical. Therefore, the results of this study can be easily applied to other microorganism, which has great significance for improving the detection level of microorganism.

PM 7/153 (1) Mechanical inoculation of test plants

PM 7/153 (1) Mechanical inoculation of test plants

One-Step Rapid and Sensitive ASFV p30 Antibody Detection via Nanoplasmonic Biosensors.

African swine fever (ASF) is one of the most serious transnational swine diseases in the world. The case fatality rate of susceptible pigs is up to 100%. Currently, no commercial vaccine is available, so the prevention and control of ASF mainly relies on early diagnosis and culling of infected pigs. As the ASF virus continues to evolve, develop, and diversify, nucleic acid testing becomes less efficient. Here, we developed a method for the rapid and direct optical measurement of African swine fever virus (ASFV) antibody in vitro. This one-step procedure requires nearly no sample preparation and involves p30 protein-specific label-free integration into standard 96-well plates. Using a nanoplasmonic biosensor with extraordinary optical transmission (EOT) effect, one-step sample addition, ASFV antibody was detected within 20 min. The positive antibody showed a satisfactory sensitivity and linear relationship in the dilution ratio of 1:100-1:16000. It was used for the detection of clinical serum samples with a coincidence rate of 96.6%. The measurement results can be automatically analyzed and displayed on a conventional microplate meter computer and connected device. Our detection method can be widely applied in point-of-care testing (POCT) of ASFV antibody in pig farms. IMPORTANCE African swine fever (ASF) is a serious transnational disease caused by the African swine fever virus (ASFV), which is highly contagious in wild boars and domestic pigs. There is currently no available vaccine for ASF; therefore, development efforts are a key priority as ASFV continues to evolve and diversify. The ASF antibody rapid detection platform comprising the nanoplasmonic biosensor with extraordinary optical transmission effect can greatly reduce the detection time and improve detection flux while maintaining detection sensitivity and specificity. The one-step sample addition can effectively avoid cross contamination of samples in the detection process. The detection method provides a solution for the rapid and accurate real-time monitoring of ASF in pig farms.

PM 3/66 (3) Guidelines for the management of plant health risks of biowaste of plant origin

<scp>PM</scp> 3/66 (3) Guidelines for the management of plant health risks of biowaste of plant origin

Soluble chitosan derivative treats wound infections and promotes wound healing in a novel MRSA-infected porcine partial-thickness burn wound model.

Burns are physically debilitating and potentially fatal injuries. The most common etiology of burn wound infections in the US is methicillin-resistant Staphylococcus aureus (MRSA), which is particularly recalcitrant when biofilms form. The current standard of care, silver sulfadiazine (SSD) is effective in reducing bacterial load, but less effective in improving burn wound healing. New treatments that can manage infection while simultaneously improving healing would provide a benefit in the treatment of burns. Porcine models are frequently used as a model for human wound healing but can be expensive due to the need to separate wounds to avoid cross contamination. The porcine model developed in this study offers the capability to study multiple partial thickness burn wound (PTBW) sites on a single animal with minimal crosstalk to study wound healing, infection, and inflammation. The current study evaluates a wound rinse and a wound gel formulated with a non-toxic, polycationic chitosan derivative that is hypothesized to manage infection while also promoting healing, providing a potential alternate to SSD. Studies in vitro and in this PTBW porcine model compare treatment with the chitosan derivative formulations to SSD. The wound rinse and wound gel are observed to disrupt mature MRSA biofilms in vitro and reduce the MRSA load in vivo when compared to that of the standard of care. In vivo data further show increased re-epithelialization and faster healing in burns treated with wound rinse/gel as compared to SSD. Taken together, the data demonstrate the potential of the wound rinse/gel to significantly enhance healing, promote re-epithelialization, and reduce bacterial burden in infected PTBW using an economical porcine model.

Microvalve array fabrication using selective PDMS (polydimethylsiloxane) bonding through Perfluorooctyl-trichlorosilane passivation for long-term space exploration

To improve the versatility and robustness of microfluidic analytical devices for space exploration, a programmable microfluidic array (PMA) has been implemented to support a variety of missions. When designing a PMA, normally closed valves are advantageous to avoid cross contamination and leaking. However, a stable fabrication method is required to prevent these valves from sticking and bonding over time. This work presents how polydimethylsiloxane (PDMS) can be bonded selectively using chemical passivation to overcome PDMS sticking issue during long-term space exploration. First, on a PDMS stamp, the vaporized perfluorooctyl-trichlorosilane (PFTCS) are deposited under − 80 kPa and 150 °C conditions. The PFTCS was then transferred onto PDMS or glass substrates by controlling temperature and time and 15 min at 150 °C provides the optimal PFTCS transfer for selective bonding. With these characterized parameters, we successfully demonstrated the fabrication of PMA to support long-term space missions. To estimate the stability of the stamped PFTCS, a PMA has been tested regularly for three years and no stiction or performance alteration was observed. A flight test has been done with a Cessaroni L1395 rocket for high g-force and vibration test and there is no difference on PMA performance after exposure of launch and landing conditions. This work shows promise as a simple and robust technique that will expand the stability and capability of PMA for space exploration.

Preliminary Planning for Mars Sample Return (MSR) Curation Activities in a Sample Receiving Facility (SRF).

Preliminary Planning for Mars Sample Return (MSR) Curation Activities in a Sample Receiving Facility (SRF).

Protection Motivation Theory and consumers’ food safety behaviour in response to COVID-19

The threat of COVID-19 has altered consumers shopping behaviour and increased consumers' willingness to purchase food using online food delivery services. Consumers were more likely to practice strict hand hygiene measures and were concerned with food safety. Such behaviours were likely driven by the fear and threat of contracting COVID-19. This study aims to use Protective Motivation Theory (PMT) to investigate how COVID-19 affects food shopping and food safety behaviour. An online, cross-sectional study was conducted in Indonesia and Malaysia to determine the protective motivation to engage in three food shopping and hygiene practices such as i) Safe food shopping behaviour; ii) Hand hygiene and avoiding cross contamination; and iii) Use of online food delivery services. Data were analysed using descriptive statistics, Spearman rho's correlation and binary logistic regression. A total of 1180 responses were received of which 1129 were valid. Gender was identified as a significant predictor across all food safety behaviours during COVID-19. Response efficacy and self-efficacy were significant predictors for food shopping behaviour while perceived severity significantly predicted hand hygiene practices after shopping. Age, frequency of food preparation and shopping, perceived severity, perceived vulnerability, response efficacy and self-efficacy were significant predictors for use of online food delivery services. Our findings suggest that women were more likely to engage in protective measures during food shopping, carry out hand hygiene practices after shopping and use online food delivery services during COVID-19. Participants with higher response and self-efficacy scores were more likely to shop from markets or shops with high hygiene standards while participants who perceived COVID-19 as a serious threat were more likely to clean and sanitise their hands after shopping. Participants also believed that the use of online food delivery services helps to reduce the risk of COVID-19 infection. However, foods should be purchased from trusted restaurants or takeaways. This is the first study to use Protection Motivation Theory to explore consumers' food shopping, hand hygiene and online food delivery practices during COVID-19.

Bacteriological assessment of a salted pork product (Unaminung) sold in Calabar metropolis

The study was carried out to evaluate the microbiological quality of Unaminungsold at watt market in Calabar,Nigeria.Samples of Commercial Ui (CUi) from three processors (P1, P2, P3) were assessed for Total Bacteria Count (TBC, log cfu/g) and Total Fungi Count (TFC, log cfu/g)using standard procedures.The bacteria and Fungi isolates were also characterized and identified.The TBC of 3.36 ±0.02 (P2) was higher than 3.17±0.20 (P3) and 3.07±0.11(P1).The bacteria isolated were identified asBacillus spharius, Staphylococcus epidermidis, Staphylococcus aureus, Streptococcus avium, Aerococcusviridans. while the fungi isolatewere Verticilliumalbo-atrum, Rhyzopusstolonifera, Penniciliumcitrinum, Candida pseudotropicalis, Candida tropicalis, Saccharomyces estuary.The results revealed that the hygienic condition of the meat was within acceptable standard for human consumption. There is need for the processors to be educated on proper handling and personal hygiene to avoid cross contamination during processing.

Dogs’ Preference for White Coat versus No White Coat When Offered a Food Reward in the Exam Room

The wearing of a white lab coat during a visit to the veterinarian is common practice in veterinary medicine to avoid cross contamination or the spread of diseases in a clinical setting. “White Coat Effect” in both human and animal medicine has been of research interest. This study sought to explore if the visual of a white coat does in fact play a role in eliciting avoidance in dogs measured by preference for a veterinarian wearing a white coat versus one not wearing it. We investigated whether dogs would choose to retrieve a food reward from the veterinarian not wearing a white coat more often. We predicted that dogs would approach the veterinarian not wearing a coat first, would avoid approaching the veterinarian with the white coat, and would spend more time around the veterinarian not wearing the coat. A modified conditioned place preference paradigm was used to design this study. Two veterinarians were in a room, one wearing a white coat and one not wearing it, with a dog and the dog’s owner. Data was recorded for how many times the dog approached each of the veterinarians, and how much time it spent in proximity of the individuals in the room. Dogs showed preference for the veterinarian not wearing a white coat and spent more time between the owner and the veterinarian not wearing a coat. This study gives insight on how veterinarians can decrease stress during a vet visit. The white coat appears to be a stressor making the visit to the vet more challenging to the canine patient. Veterinarians and staff shall provide a comfortable setting for patients so that they can properly assess and treat them, while decreasing fear of the vet visit.

Microbial Load in Kitchen Dish Wash Scrubber

Introduction: Kitchen sponges are most commonly used cleaning equipment. These sponges were heavily contaminated with the microorganisms which acts as a carrier of food borne diseases. It provides favourable conditions for the growth of bacteria and other microorganisms. It acts as a reservoir of pathogens and a vector of cross contamination. Proper sanitization techniques must be followed to avoid cross contamination.&#x0D; Aim: The aim of the study was to evaluate the microbial load in used kitchen dish wash scrubbers.&#x0D; Materials and Method: Twenty dish wash scrubbers were collected in a sterile disposable container. Moisture was removed by drying the scrubber. The procedures were conducted after 5 days. Measured the weight of the scrubber weighing 1 gram and soaked it in 500 ml of sterile saline for 30 minutes, agitated it and transferred 10 microliter to the media. And identified the organisms by the growth characters on the media for the possible pathogens.&#x0D; Result: From the growth characters the organisms identified were Coliform, Bacillus and Staphylococcus.&#x0D; Conclusion: This study showed that scrubbers were not clean and were at increased risk of food poisoning. Kitchen sponges were highly contaminated with potentially pathogenic bacteria which might be transferred from the overall kitchen environment to food contact surfaces and consequently cause food contamination.

Prevalence of Soil Transmitted Helminths in Some Birds Kept at Federal University Of Agriculture Abeokuta (FUNAAB) Zoo Park, Abeokuta, Nigeria

Captive-held wild animals are those housed in zoological exhibits, rehabilitation centres, zoos, research stations, sanctuaries, aquaria, circuses, and plantations. However, parasitic diseases constitute one of the major problems causing mortality in these animals while in captivity. The effects range from sub-clinical to death; hence, the study was conducted to assess the gastrointestinal parasite profile of birds kept in Federal University of Agriculture, Abeokuta ZooPark. Freshly voided faecal samples of Psittacus erithacus, Psittacula krameri, Balaerica pavonina, pavo cristatus, Chen caerulescens, Struthio camelus and Anas platyrhynchos were collected before routine cleaning. Samples were collected weekly for 8 weeks between 7am- 9am within the month of October and November, 2019. A total of 56 faecal samples from 7 birds were picked from the ground by utilizing a sterile scoop for each animal species to avoid cross contamination. Each sample was put in a new labelled sterile bottle with the name of each bird from which the faecal sample was collected. Samples were then transported to the laboratory for microscopic analysis which was done within 24 hours. Egg counting was done using the McMaster Egg Counting Technique. Identification of intestinal helminth ova was done by using the keys. Data obtained were analysed using SPSS version 20.0 and Microsoft excel. Prevalence was calculated while the weekly egg counts of intestinal helminthes were presented using descriptive statistics. The distribution of intestinalhelminthes infections among the surveyed birds vary from (Psittacula krameri 100%, pavo cristatus 100%, Psittacus erithacus 66.67%, Balaerica pavonina 66.67%, Chen caerulescens 66.67%, Struthio camelus 66.67%, and Anas platyrhynchos 66.67%). In conclusion, the prevalence of soil transmitted helminthes revealed that Ascaridiagalli andStrongyloides spp had the highest prevalence among the birds with 100% while Raillietina spp recorded the lowest prevalence with 28.6%.

Microbiological Evaluation and Public Health Implication of Frozen Scomber Scombrus Sold in Selected Markets of Imo Sate, Nigeria

A comparative study was done on the microbiological quality of frozen Scomberscombrus sold in cold room and open markets of Imo state and its public health implication on the final consumers was highlighted. Results revealed nine bacterial species and seven fungal species contaminating the fish but with higher values in the open markets than in the cold room which is attributed to the possible environment of the open market in the study area as temperature increases outside of the cold room storage, pH level reduces as fish starts to deteriorate and concentration rises as water condenses out of the fish with each drip leading to the production of conducive environment for microbial growth and the proliferation of such. Added factors are the exposure of cold room fish to improper handling during transportation, and exposure to environmental contaminants during conspicuous displays and handling at the marketstands. Bacteria isolated such as Salmonella, Staphylococcus spp., Escherichia spp. and Enteroviruses are implicated as the most fish related food-borne pathogens and posing different levels of hazards to consumers. It is therefore recommended that traders and consumers should by all means adopt better hygienic and handling practice and also avoid cross contamination of fresh fish with cooked- ready to eat fish because these two processed types are occasionally sold in same environment. The health safety of all persons lies in the hands of all stakeholders through the food production, storage, processing, transportation and consumption stages.

P–153 Comparison outcome of vitrified human embryos stored in vapor phase liquid nitrogen (LN2) and direct LN2

Abstract Study question Is vapor cryopreserved LN2 storage beneficial for clinical outcomes of vitrified human embryos that are frozen compared to vitrified human embryos having direct contact with LN2. Summary answer There are no significant differences compared to clinical outcomes of human embryos stored in LN2 vapor and direct store in LN2. What is known already There has been concerned about potential cross-contamination and biohazard issues of embryos for long term storage using direct LN2. This study aimed to compare clinical outcomes of human embryos transfer between vapor phase and liquid LN2. Study design, size, duration The embryo has undergone vitrification for long term storage with vapor or direct contact in LN2. After the thawing of the embryo, we checked on the survival rates. We transferred only one or two embryos per patient and kept analyzing the implantation and pregnancy rates Participants/materials, setting, methods This retrospective study was carried out from January 2018 to December 2019 with 3272cycles 4713embryos; vitrified for long term storage in vapor phase or direct contact with LN2. We compared the clinical outcomes of frozen embryo transfer cycles using vitrified for long term storage in vapor phase and direct contact with LN2. Clinical outcomes monitored were embryo survival, subsequent implantation and pregnancy after single or double embryo transfer Main results and the role of chance A total of 4713 fertilized human embryos are vitrified and then stored in LN2 vapor (n = 2520 cycles) or direct contact LN2 (n = 752 cycles). The study showed that the blastocyst stored in vapor able to retain full development. Survival was 97.8% (vapor) and 97.6% (direct contact LN2), and the vapor storage of human embryos had no significant difference in survival rates after a long term storage. For single blastocyst transfer, pregnancy and implantation rates were 51.5%, 52.4% in vapor, 54.6%, 54.9% in direct LN2; respectively (p=NS). In double blastocyst transfer, the pregnancy and implantation rates were 61.8%, 42.0% in vapor and 64.7%, 44.5% in direct LN2; respectively (p=NS). There were also no significant differences between two groups. Limitations, reasons for caution The study showed that the blastocyst stored in vapor can retain full development. A vapor storage system thus is safe and effective for long term vapor storage of vitrified human embryos.Within the limits of this study, there was no detection of an adverse effect of vapor storage. Wider implications of the findings: Vapor storage systems thus represent a useful alternative for safe and effective long-term storage of vitrified human embryos that can avoid cross contamination chances from having direct contact with LN2. Trial registration number Not applicable

Types of bacteria isolated from Yemeni Currencies in Sana'a City and potential risk factors

The main objective of this study was to determine the prevalence of bacterial contaminants on Yemeni paper currency notes and coins and some potential risk factors. This study was carried out on 140 paper currency and coins obtained from bus drivers, supermarket cashers and Qat sellers shops in Sana'a city, Yemen. Swabs were taken from 140 paper currencies and coins and were cultured on Blood and MacConkey agars. Gram stain, biochemical and serological tests were done to identify isolated bacteria. The percentage of different types of bacteria isolated from the currencies were as follow; Staphylococci spp (22.2%), Alcaligenes spp (11.2%) , Pseudomonas aeruginosa and, Gram positive bacilli (10.0%), Escherishia coli (9.3%) , Seratia marcescans (6.8 %) , Streptococci spp (5.3%) , Enterobacter aerogene (3.0%) , Klebsilla pneumoniae (3.0%) , Enterobacter cloacae (2.3%) , Yersinia enterocolitica (2.3%) , Citrobacter spp (2.3%) , Gram posative diplococci (1.5%) , Shigella spp (1.5%) , and same percentage (0.8%) of Gram negative cocci, Vibrio cholerae, Actinomysis spp, Proteus vulgaris, Proteus mirabilis. The highest percentage of Gram negative and Gram positive bacteria was found on currencies taken from supermarket cashers (31.4%) and (30.4), respectively. Whereas, lowest percentage were found in currencies taken from bus driver and Qat seller shops. Yemeni paper currency and coins are contaminated with pathogenic bacteria. Currency contamination is of importance issue to public health as it can provide a vehicle for easy transmission of pathogens between handlers. Therefore, public education on proper handling and great care should be taken during handling of money to avoid cross contamination.

Comparative Bacteriological Evaluation of Frozen and Salt Water Tilapia Fishes (Oreochromos niloticus and Oreochromos aureus) Sold in Port Harcourt, Rivers State Nigeria

Fishes are highly perishable, and prone to vast variations in quality due to differences in species, feeding habits as well as the environmental and preservation factors. This study Compared the bacteriological quality of Frozen and Salt Water Tilapia Fishes (Oreochromos niloticus and Oreochromos aureus) sold in Port Harcourt, Nigeria. Total number of sixty (60) samples were evaluated. Frozen tilapia (36) and salt water tilapia fishes (24) were obtained from the three sampling markets using sterile bags which were properly labelled. The samples were transported to the Laboratory for analyses within 2 hours of collection in a thermos box containing ice pack and standard microbiological procedures were employed in the bacteriological evaluations. Different parts of the fishes such as Intestine, gills and flesh of the samples were dissected and used for bacteriological analysis. Statistical analyses were carried out using ANOVA and All pairs tukey- kramer. Results obtained from the study showed that the highest number of total heterotrophic bacteria count was obtained from frozen fish gills which was 7.7 x 106±0.98 cfu/g while the least count of 4.7 x 106±0.67 cfu/g was from salt water tilapia fish flesh. Total coliform count ranged from 3.3 x104±0.91 cfu/g to 8.0 x104±0.44a cfu/g for salt water flesh and frozen fish intestine from different markets respectively. Listeria species count ranged from 1.3 x104± 0.30 cfu/g to 4.3 x104±0.57 cfu/g for salt water fish intestine and frozen fish flesh respectively. Total Salmonella count ranged from 1.0 x103±0 cfu/g to 6.2x103±1.30cfu/g for frozen fish flesh and salt water fish intestine. These values were above the WHO permissible limit. Mean values for all the microbial counts were significantly different at (P&lt;0.05) in the two samples across the sampled markets comparatively, frozen fish has more bacteriological load than salt water fish, this may be attributed to the handling, hygiene storage of the respective fishes as well as storage conditions. Listeria species were identified as L. monocytogenes, L. graji, L. seeligeri, L. ivanovii, and L. welshmeri by genomic studies. While three species of Salmonella such as S. arizonae, S. gallinarum, S. typhi were isolated. Other bacterial isolates were identified as Vibrio spp, Bacillus spp Staphylococcus spp Shigella spp Pseudomonas spp. Enterobacter spp. E. coli, Micrococcus spp. Acinetobacter spp. Klebsiella spp. This study revealed that fish sold at different markets in Port Harcourt especially frozen fish, is highly contaminated with different kinds of bacterial pathogens which may constitute potential public health hazard due to the unhygienic nature of fish vendors which predisposes frozen fishes to contamination by pathogenic microorganisms. Therefore proper blanching and heating methods should be employed during preparations of fishes to avoid cross contamination and food intoxication/ poisoning before consumption. It is important that all hazard analysis critical control point be adhered to for good production processes.

Full-size experimental assessment of the aerodynamic sealing of air curtains for particulate matter

An air curtain is used to ensure an adequate separation between two compartments that is aimed to restrict, a clean one and a contaminated one. The air curtain performance is improved with the use of an air extraction from the “contaminated” compartment. The aerodynamic sealing of an optimized air curtain is assessed regarding particulate matter. The evaluation using visual assessment of the aerodynamic sealing using a cold smoke source is validated against PM 10 detection. It is shown that the air curtain presents a good aerodynamic sealing for the particulate of PM10 and PM2.5 classes and that the visual assessment method can lead to similar results. An equation was obtained with a view to be used to predict the level of aerodynamic sealing of the air curtain when the exhaust rate becomes too low. Another equation was obtained for predicting the average velocity through the door protected by the air curtain required to obtain an aerodynamic sealing, as a function of the jet parameters (nozzle average velocity and thickness). These test results prove that the air curtain, complemented with an air exhaust from the “contaminated compartment”, is suitable to provide an acceptable aerodynamic sealing for the particulate matter. Practical application: The findings of this research are applicable when it is necessary to retain the contamination due to particulate matter using a soft boundary, as air plane jets. This is applicable to medical care centres to reduce the possibility of contamination due to bacteria between different compartments or in pharmaceutical process units to avoid cross contamination among them.

Day to Day Use of Disinfectant Methods for Different Impression Materials among Dental Practitioners

One of the major problems which most dental professionals face is cross contamination and cross infection. During the fabrication of dental prosthesis, special care should be taken for every step, especially impressions as they are one of the main concern. This is because impressions are one of the most known to be the main source of infection for any potentially infectious material . To check the practice of disinfection level among the dental practitioners, a questionnaire containing 15 questions was prepared. This survey was carried between the month of June 2019 to March 2020 among the dental practitioners living in Chennai, Tamil Nadu, India. This survey was carried under an online platform where the participants responded to their answers. Based on their responses, the result was tabulated. We got a result of about 64% practitioners practicing protocol to disinfect impressions 65% use alginate to take impressions. 44% use 2% glutaraldehyde to disinfect impressions. 46% prefer spraying disinfectant over impression tray. Based on much research, it was reported that dental technicians were suffering from infections in hand restoratory systems, so on humanitarian basis we dentists can take better measures ourselves in avoiding cross contamination to fellow dental technicians by following proper and simple methods for disinfection of impressions before sending them to dental laboratories. To conclude awareness workshops, programs must be organised to create awareness among dentists to present cross infections.

Evaluation of a sanitizing washing step with different chemical disinfectants for the strawberry processing industry

Strawberries are often consumed fresh or only receive minimal processing, inducing a significant health risk to the consumer if contamination occurs anywhere from farm to fork. Outbreaks of foodborne illness associated with strawberries often involve a broad range of microbiological agents, from viruses (human norovirus) to bacteria (Salmonella spp. and Listeria monocytogenes). The addition of sanitizers to water washes is one of the most commonly studied strategies to remove or inactivate pathogens on berries as well as avoid cross contamination due to reuse of process wash water. The risk posed with the safety issues of by-products from chlorine disinfection in the fruit industry has led to a search for alternative sanitizers. We evaluated the applicability of different chemical sanitizers (peracetic acid (PA), hydrogen peroxide (H2O2), citric acid (CA), lactic acid (LA) and acetic acid (AA)) for the inactivation of S. enterica, L. monocytogenes and murine norovirus (MNV-1) on strawberries. A control treatment with chlorine (NaClO) (100 ppm) was included. For each sanitizer, different doses (40, 80 and 120 ppm for PA and 1, 2.5 and 5% for H2O2, LA, AA and CA) and time (2 and 5 min) were studied in order to optimize the decontamination washing step. The best concentrations were 80 ppm for PA, 5% for H2O2 and 2.5% for organic acids (LA, AA and CA) after 2 min treatment. Results indicate that the sanitizers selected may be a feasible alternative to chlorine (100 ppm) for removing selected pathogenic microorganisms (P > 0.05), with reductions about ≥2 log for bacterial strains and ≥ 1.7 log for MNV-1. As the washing water may also increase the microbial counts by cross-contamination, we observed that no pathogenic bacteria were found in wash water after 5% H2O2 and 80 ppm PA after 2 min treatment. On the other hand, we also reported reductions about total aerobic mesophyll (TAM) (0.0–1.4 log CFU/g) and molds and yeasts (M&Y) (0.3–1.8 log CFU/g) with all alternative sanitizers tested. Strawberries treated did not shown significant differences about physio-chemical parameters compared to the untreated samples (initial). For this study, the optimal sanitizer selected was PA, due to the low concentration and cost needed and its microbiocidal effect in wash water and fruit. Notwithstanding the results obtained, the effect of PA in combination with other non-thermal technologies such as water-assisted ultraviolet (UV-C) light should be studied in future research to improve the disinfection of strawberries.