Antibacterial Activity of Oregano (Origanum vulgare L.) Essential Oil Vapors against Microbial Contaminants of Food-Contact Surfaces

The antimicrobial effect of eight essential oils' vapors against pathogens and spoilage bacteria was assayed. Oreganum vulgare L. essential oil (OVO) showed a broad antibacterial effect, with Minimum Inhibitory Concentration (MIC) values ranging from 94 to 754 µg cm-3 air, depending on the bacterial species. Then, gaseous OVO was used for the treatment of stainless steel, polypropylene, and glass surfaces contaminated with four bacterial pathogens at 6-7 log cfu coupon-1. No viable cells were found after OVO treatment on all food-contact surfaces contaminated with all pathogens, with the exception of Sta. aureus DSM 799 on the glass surface. The antimicrobial activity of OVO after the addition of beef extract as a soiling agent reduced the Sta. aureus DSM 799 viable cell count by more than 5 log cfu coupon-1 on polypropylene and glass, while no viable cells were found in the case of stainless steel. HS-GC-MS analysis of the headspace of the boxes used for the antibacterial assay revealed 14 different volatile compounds with α-Pinene (62-63%), and p-Cymene (21%) as the main terpenes. In conclusion, gaseous OVO could be used for the microbial decontamination of food-contact surfaces, although its efficacy needs to be evaluated since it depends on several parameters such as target microorganisms, food-contact material, temperature, time of contact, and relative humidity.

Re-Evaluating Cross-Contamination: Additional Trials on Co-Ventilation

BACKGROUND

Medical equipment can become scarce in disaster scenarios. Prior work has reported that four sheep could be ventilated together on a single ventilator. Others found that this maneuver is possible when needed, but no one has yet investigated whether cross-contamination occurs in co-ventilated individuals.

OBJECTIVE

Our goal was to investigate whether an infection could spread between co-ventilated individuals.

METHODS

Four 2-L anesthesia bags were connected to a sterilized ventilator circuit that used heat and moisture exchange filters and bacterial and viral filters, as would be expected in this dire scenario. Serratia marcescens was inoculated into "lung" no. 1. After running for 24 h, each lung and three additional points in the circuit were cultured to see whether S. marcescens had spread. These cultures were examined at 24 and 48 h to assess for cross-contamination. This entire procedure was performed three times.

RESULTS

S. marcescens was not found in lung no. 2, 3, or 4 or the three additional sites on the expiratory limb at 24 and 48 h in all three trials.

CONCLUSIONS

Cross-contamination does not occur within 24 h using the described ventilator circuit configuration.

Homology Identification and Cross-Contamination Analysis: A Method for Evaluating the Quality of Biological Samples Stored in a Biobank Using the Advanta Sample ID Genotyping Panel

Biological samples are important resources for scientific research. These samples are stored in biobanks over years until needed, and some of them can never be retrieved if they are improperly stored, causing them to be wasted. Thus, they are priceless, and they should be used correctly and effectively. Sample quality substantially affects biomedical research results. However, sample misidentification or mix-up is common. It is necessary to establish quality standards for sample identification. In this study, we used the Advanta Sample ID genotyping panel to detect homology identification and cross-contamination. We compared the single-nucleotide polymorphism (SNP) typing results of two different samples and calculated the similarity score of homologous sample pairs and nonhomologous sample pairs. Through analysis, we obtained a similarity score cutoff point of 0.8620, which was an effective way to distinguish homology and nonhomology. Cross-contamination was detected in two sets of mixtures (STD8:STD6 and jj3:1-P) mixed at a series of special ratios. Sensitivity was dependent on the sample characteristics and mixing ratios. Finally, we assessed the effect of sample degradation degree on SNP genotyping and found that degraded samples with a minimal DNA integrity number of 1.9 had complete genotyping results. On the whole, this study shows that the Sample ID panel is reliable for homology identification and cross-contamination analysis. Moreover, this technology has promising further applications in biological sample quality control.

Nasopharyngeal Carcinoma Cell Lines: Reliable Alternatives to Primary Nasopharyngeal Cells?

Nasopharyngeal carcinoma (NPC) is a type of cancer that originates from the mucosal lining of the nasopharynx and can invade and spread. Although contemporary chemoradiotherapy effectively manages the disease locally, there are still challenges with locoregional recurrence and distant failure. Therefore, it is crucial to have a deeper understanding of the molecular basis of NPC cell movement in order to develop a more effective treatment and to improve patient survival rates. Cancer cell line models are invaluable in studying health and disease and it is not surprising that they play a critical role in NPC research. Consequently, scientists have established around 80 immortalized human NPC lines that are commonly used as in vitro models. However, over the years, it has been observed that many cell lines are misidentified or contaminated by other cells. This cross-contamination leads to the creation of false cell lines that no longer match the original donor. In this commentary, we discuss the impact of misidentified NPC cell lines on the scientific literature. We found 1159 articles from 2000 to 2023 that used NPC cell lines contaminated with HeLa cells. Alarmingly, the number of publications and citations using these contaminated cell lines continued to increase, even after information about the contamination was officially published. These articles were most commonly published in the fields of oncology, pharmacology, and experimental medicine research. These findings highlight the importance of science policy and support the need for journals to require authentication testing before publication.

Botanical Impurities in the Supply Chain: A New Allergenic Risk Exacerbated by Geopolitical Challenges

BACKGROUND

The supply chains of food raw materials have recently been heavily influenced by geopolitical events. Products that came from, or transited through, areas currently in conflict are now preferentially supplied from alternative areas. These changes may entail risks for food safety.

METHODS

We review the potential allergenicity of botanical impurities, specifically vegetable contaminants, with particular attention to the contamination of vegetable oils. We delve into the diverse types of botanical impurities, their sources, and the associated allergenic potential. Our analysis encompasses an evaluation of the regulatory framework governing botanical impurities in food labeling.

RESULTS

Unintended plant-derived contaminants may manifest in raw materials during various stages of food production, processing, or storage, posing a risk of allergic reactions for individuals with established food allergies. Issues may arise from natural occurrence, cross-contamination in the supply chain, and contamination at during production. The food and food service industries are responsible for providing and preparing foods that are safe for people with food allergies: we address the challenges inherent in risk assessment of botanical impurities.

CONCLUSIONS

The presence of botanical impurities emerges as a significant risk factor for food allergies in the 2020s. We advocate for regulatory authorities to fortify labeling requirements and develop robust risk assessment tools. These measures are necessary to enhance consumer awareness regarding the potential risks posed by these contaminants.

Analysis of two cross-contamination cases of Campylobacter jejuni foodborne disease in fragile subjects in the territory of a Local Health Authority in Tuscany, Italy

Campylobacteriosis is the most reported foodborne disease in the European Union, with more than 100,000 confirmed cases annually. Human infection can be caused by a low infectious dose, and in fragile populations, the food disease can manifest itself in acute and severe forms. This study aims to analyze two cases of campylobacteriosis in fragile people caused by Campylobacter jejuni in 2023 in Tuscany and the actions of the Local Health Competent Authority. From the results of the related investigations, it was possible to attribute both cases of foodborne diseases to unsafe food management during preparation/administration. Given the peculiar characteristics of the etiological agent, it is necessary to focus the attention of the population, especially those who deal with fragile subjects, on the good hygiene practices to be followed both at home and in collective catering.

Multiple approaches revealed MGc80-3 as a somatic hybrid with HeLa cells rather than a gastric cancer cell line

The short-tandem-repeats (STR) profiles of MGc80-3 and HeLa partially overlap, raising suspicion of contamination in the MGc80-3 cell line. However, there has not been any relevant study demonstrating whether MGc80-3 was fully replaced by HeLa cells, just mixed with HeLa cells (co-existing), or was a somatic hybrid with HeLa cells. In addition to STR profiling, various approaches, including single nucleotide polymorphisms genotyping, polymerase chain reaction, screening for human papillomaviruses type 18 (HPV-18) fragment, chromosome karyotyping, pathological examination of xenografts, tissue-specific-90-gene expression signature and high-throughput RNA sequencing were used to determine the nature of MGc80-3. Our study found that the abnormal STR profile, partially overlapping with that of HeLa cells (64.62% to 71.64%), could not verify MGc80-3 as a HeLa cell line. However, the STR 13.3 repeat allele in the D13S317 locus that seemed to be unique to HeLa cells was detected in MGc80-3. Almost all the MGc80-3 cells exhibited HPV-18 fragments in the genome as well as certain HeLa marker chromosomes, such as M7 and M12. The molecular assay of the 90-gene expression signature still considered MGc80-3 as a stomach cancer using an algorithmic analysis. The expression pattern of multiple genes in MGc80-3 was quite different from that in HeLa cells, which showed that certain characteristics belonged to gastric cancer cell lines. High throughput RNA sequencing showed the distinct patterns of gene expression in MGc80-3. In conclusion, MGc80-3 cell line is a somatic hybrid with HeLa cells rather than a pure gastric cancer cell line.

An assessment of bacterial contamination of indirect ophthalmoscopes and condensing lenses used in clinical practice: A multi-center study

PURPOSE

To investigate bacterial contamination of indirect ophthalmoscopes and condensing lenses used in three UK veterinary referral centers, and the impact of an implemented cleaning protocol.

METHODS

Bacteriology samples from 10 indirect ophthalmoscopes and 10 condensing lenses were taken at each center (n = 30 T0), before initiating one of three cleaning frequencies (every 2 weeks/once weekly/daily) for 28 days. The most contaminated indirect ophthalmoscope and condensing lens from each center were re-sampled 30 min prior to (T1; n = 9) and 30 min after (T2; n = 9) the final clean. Sensitivity testing was completed using MIC.

RESULTS

Seventy-three isolates representing 15 different bacterial populations (genus/species) were cultured from 36 of 48 (75%) swabs tested. The most frequently cultured isolates were Staphylococcus spp. 30%, Micrococcus 22%, and Bacillus 14%. Pseudomonas aeruginosa, Pantoea, and Staphylococcus pseudintermedius demonstrated resistance to >50% of antibiotics against which they were tested. Eighty-three percent of T0 samples (54 isolates across 11 species, median 2 isolates/swab), all T1 samples (15 isolates across 8 species, median 2 isolates/swab), and 22% of T2 samples (4 isolates across 4 species, median 0 isolates/swab) were contaminated. Head contact points were most contaminated irrespective of time point. A T1 sample was 57 times more likely (95% CI: 2.4-1376) to have a positive culture than a T2 sample (p = .01).

CONCLUSIONS

Baseline contamination was high, representing a potential source of nosocomial infection in ophthalmic patients and handlers of diagnostic equipment. No center implemented a cleaning protocol prior to this study. Routine cleaning reduces bacterial contamination.

Systematic Review and Meta-Analysis of Campylobacter Species Contamination in Poultry, Meat, and Processing Environments in South Korea

Campylobacter spp. constitute a significant global threat as a leading cause of foodborne illnesses, with poultry meat as a prominent reservoir for these pathogens. South Korea is known for its diverse poultry consumption habits, and continuous outbreaks make it a matter of concern to perform a meta-analysis to identify the primary source of contamination. This systematic review and meta-analysis aimed to assess and compare the prevalence of Campylobacter in various poultry and meat types while also considering the importance of environmental factors in South Korea. The meta-analysis revealed that duck meat exhibited the highest prevalence of Campylobacter, with a pooled estimate of 70.46% (95% CI: 42.80% to 88.38%), followed by chicken meat at a pooled prevalence of 36.17% (95% CI: 26.44% to 47.91%). Additionally, our analysis highlighted the predominance of C. jejuni and C. coli in South Korea. These findings underscore the importance of implementing rigorous food safety measures and establishing robust surveillance programs in the poultry industry to mitigate the risk of Campylobacter-related foodborne illnesses associated with meat consumption in South Korea.

Unveiling Fresh-Cut Lettuce Processing in Argentine Industries: Evaluating Salmonella Levels Using Predictive Microbiology Models

A survey was performed to gather information on the processing steps, conditions, and practices employed by industries processing ready-to-eat (RTE) leafy vegetables in Argentina. A total of seven industries participated in the survey. A cluster analysis of the data obtained was performed to identify homogeneous groups among the participating industries. The data collected were used as inputs of two predictive microbiology models to estimate Salmonella concentrations after chlorine washing, during storage and distribution of final products, and to rank the different practices according to the final estimated Salmonella levels. Six different clusters were identified by evaluating the parameters, methods, and controls applied in each processing step, evidencing a great variability among industries. The disinfectant agent applied by all participating industries was sodium hypochlorite, though concentrations and application times differed among industries from 50 to 200 ppm for 30 to 110 s. Simulations using predictive models indicated that the reductions in Salmonella in RTE leafy vegetables would vary in the range of 1.70-2.95 log CFU/g during chlorine-washing depending on chlorine concentrations applied, washing times, and vegetable cutting size, which varied from 9 to 16 cm2 among industries. Moreover, Salmonella would be able to grow in RTE leafy vegetables during storage and distribution, achieving levels of up to 2 log CFU/g, considering the storage and transportation temperatures and times reported by the industries, which vary from 4 to 14 °C and from 18 to 30 h. These results could be used to prioritize risk-based sampling programs by Food Official Control or determine more adequate process parameters to mitigate Salmonella in RTE leafy vegetables. Additionally, the information gathered in this study is useful for microbiological risk assessments.

Modeling of interventions for reducing external Enterobacteriaceae contamination of broiler carcasses during processing

This article presents a mathematical model for the Enterobacteriaceae count on the surface of broiler chicken during slaughter and how it may be affected by different processing technologies. The model is based on a model originally developed for Campylobacter and has been adapted for Enterobacteriaceae using a Bayesian updating approach and hitherto unpublished data gathered from German abattoirs. The slaughter process in the model consists of five stages: input, scalding, defeathering, evisceration, washing, and chilling. The impact of various processing technologies along the broiler processing line on the Enterobacteriaceae count on the carcasses' surface has been determined from literature data. The model is implemented in the software R and equipped with a graphical user interface which allows interactively to choose among different processing technologies for each stage along the processing line. Based on the choice of processing technologies the model estimates the Enterobacteriaceae count on the surface of each broiler chicken at each stage of processing. This result is then compared to a so-called baseline model which simulates a processing line with a fixed set of processing technologies. The model calculations showed how even very effective removal of bacteria on the exterior of the carcass in a previous step will be undone by the cross-contamination with leaked feces, if feces contain high concentrations of bacteria.

Fatal neonatal listeriosis following L. monocytogenes horizontal transmission highlights neonatal susceptibility to orally acquired listeriosis

We report a case of fulminant fatal neonatal listeriosis due to horizontal transmission of Listeria monocytogenes (Lm) in a neonatal double room. Genomic analyses reveal a close genetic relationship between clinical isolates, supporting cross-contamination. Oral inoculation experiments in adult and neonatal mice show that neonates are susceptible to a low Lm inoculum and that this susceptibility results from the immaturity of the neonatal gut microbiota. Infected neonates should therefore be isolated for as long as they shed Lm in their feces to avoid horizontal transmission and its dire consequences.

Use of Essential Oil Emulsions to Control Escherichia coli O157:H7 in the Postharvest Washing of Lettuce

Essential oils (EOs) have strong antibacterial properties and can be potential sanitizers to reduce pathogen load and prevent cross-contamination during postharvest washing. The objective of this study was to investigate the efficacy of emulsions containing oregano (OR; Origanum vulgare) and winter savory (WS; Satureja montana) EOs at different concentrations (0.94 and 1.88 µL/mL) and storage times (0 h, 24 h, and 7 days), in reducing Escherichia coli O157:H7 on the surface of three types of lettuce (romaine, crisphead, and butterhead). The EO emulsions were compared with one no-rinse treatment and three rinse treatments using water, 200 ppm chlorine, and 80 ppm peroxyacetic acid (PAA), respectively, in a simulated washing system. The results showed that while the EO emulsions significantly reduced E. coli O157:H7 on crisphead lettuce over time, not all treatments were effective for romaine and butterhead lettuce. The mixture of OR and WS at concentrations of 0.94 and 1.88 µL/mL was found to be the most effective in reducing E. coli O157:H7 on inoculated lettuce, resulting in reductions of 3.52 and 3.41 log CFU/g, respectively. Furthermore, the PAA and the mixture of OR and WS at 1.88 µL/mL effectively limited bacterial cross-contamination close to the detection limit for all lettuce types during all storage times. These results suggest that OR and WS EOs could serve as potential alternatives to chemical sanitizers for postharvest lettuce washing.

Quantitative microbiological risk assessment of nontyphoidal Salmonella in ground pork in households in Chengdu, China

Foodborne disease caused by nontyphoidal Salmonella (NTS) is one of the most important food safety issues worldwide. The objectives of this study were to carry out microbial monitoring on the prevalence of NTS in commercial ground pork, investigate consumption patterns, and conduct a quantitative microbiological risk assessment (QMRA) that considers cross-contamination to determine the risk caused by consuming ground pork and ready-to-eat food contaminated during food handling in the kitchen in Chengdu, China. The food pathway of ground pork was simplified and assumed to be several units according to the actual situation and our survey data, which were collected from our research or references and substituted into the QMRA model for simulation. The results showed that the prevalence of NTS in ground pork purchased in Chengdu was 69.64% (95% confidence interval [CI], 60.2-78.0), with a mean contamination level of -0.164 log CFU/g. After general cooking, NTS in ground pork could be eliminated (contamination level of zero). The estimated probability of causing salmonellosis per day was 9.43E-06 (95% CI: 8.82E-06-1.00E-05), while the estimated salmonellosis cases per million people per year were 3442 (95% CI: 3218-3666). According to the sensitivity analysis, the occurrence of cross-contamination was the most important factor affecting the probability of salmonellosis. To reduce the risk of salmonellosis caused by NTS through ground pork consumption, reasonable hygiene prevention and control measures should be adopted during food preparation to reduce cross-contamination. This study provides valuable information for household cooking and food safety management in China.

Quality and Purity of L929 Cell Cultures: Isoenzyme Profiles As a Sensitive Marker of Cross-Contamination

Objective: Inappropriate handling of cells can generate modifications in the genomic DNA. The additional risk is cross-contamination. Isoenzyme analysis with gel agarose electrophoresis is a known, fast, and cheap technique for detection of species-specific isoforms of intracellular enzymes. The aim of the experimental work was to check if variations in the cell growth conditions can affect morphology and/or nuclear anomalies including micronuclei (MN) in the L929 cells; and to define how sensitive and selective is the classic gel agarose electrophoresis for analysis of isoforms of the selected enzymes to detect cross-contamination of L929 cultures with HeLa cells or with the related species, such as CHO-K1 cells, in the case of unavailability of the commercial kits. Methods: The experiments were done with use of the National Collection of Type Cultures clone 929 (L929)-mouse fibroblasts from subcutaneous connective tissue; HeLa-human cervix adenocarcinoma; and CHO-K1-epithelial-like hamster ovary cells. Cell morphology was evaluated with a light/fluorescence microscope. MN were determined with the cytokinesis-block micronucleus assay, and the isoenzyme analysis was performed using gel agarose electrophoresis. Results: As shown, the overgrown cultures result in a significant increase of the MN in the L929 cells. The band patterns for lactate dehydrogenate, glucose-6-phosphate dehydrogenase, or malate dehydrogenase allow identification of the single L929, HeLa, or CHO-K1 cell line and to detect the cross-contamination, even up to 0.4%. Conclusions: There can be no exceptions from the recommended cell culture conditions in the passage scheme. The sensitivity of the gel agarose separation depends on the cells and on the type of enzyme tested and seems to be sufficient in a quick screening of the CHO-K1, L929, or HeLa cell cultures through the possible mutual contamination.

Microbubbles Remove Listeria monocytogenes from the Surface of Stainless Steel, Cucumber, and Avocado

Fresh produce may be contaminated by bacterial pathogens, including Listeria monocytogenes, during harvesting, packaging, or transporting. A low-intensity cavitation process with air being injected into water was studied to determine the microbubbles' efficiency when detaching L. monocytogenes from stainless steel and the surface of fresh cucumber and avocado. Stainless steel coupons (1″ × 2″), cucumber, and avocado surfaces were inoculated with L. monocytogenes (LCDC strain). After 1, 24 or 48 h, loosely attached cells were washed off, and inoculated areas were targeted by microbubbles (~0.1-0.5 mm dia.) through a bubble diffuser (1.0 L air/min) for 1, 2, 5, or 10 min. For steel, L. monocytogenes (48 h drying) detachment peaked at 2.95 mean log reduction after 10 min of microbubbles when compared to a no-bubble treatment. After 48 h pathogen drying, cucumbers treated for 10 min showed a 1.78 mean log reduction of L. monocytogenes. For avocados, L. monocytogenes (24 h drying) detachment peaked at 1.65 log reduction after 10 min of microbubbles. Microbubble applications may be an effective, economical, and environmentally friendly way to remove L. monocytogenes, and possibly other bacterial pathogens, from food contact surfaces and the surfaces of whole, intact fresh produce.

A Microbiological Assay of Common Operating Room (OR) Tapes: Developing a Culture for Patient Safety

BACKGROUND

There are no existing practices or methods to ensure cleanliness, sterility, or prevent cross-contamination when it comes to common operating room (OR) tape. The authors hypothesized that adhesive tapes used by anesthesia providers in ORs and off-site surgical areas might be colonized by microorganisms and that culturing these tape rolls would reveal significant monomicrobial and polymicrobial contamination.  Material and Methods: The primary objective of this observational cohort study was to report and compare contamination rate including polymicrobial contamination rate between tape specimens collected from storage site and specimen from the ORs, off-sites, and after use on a patient. The outcome measures were the culture reports of the adhesive tapes. The authors then designed an intervention that integrated anesthesia providers' hand hygiene and maintenance of a barrier between the OR tapes and OR surfaces.

RESULTS

The authors reported gross contamination and cross-contamination among the OR off-site tapes. The contamination rates reported for tapes from OR, off-site specimens, and patient specimens were 68.2%,63.2%, and 100%, respectively. The authors again cultured adhesive tapes after the intervention and reported improved outcomes.

CONCLUSIONS

The current quality improvement (QI) project identified the potential for OR tapes to serve as microbial vectors. The authors advocate environmental decontamination and anesthesia providers' hand hygiene in parallel as a part of routine anesthesia care in their practice and agree that the endotracheal tubes (ETTs) and orogastric or nasogastric tubes should be pre-packaged with single-use tape, which can be used for securing devices.

Lifestyle of Listeria monocytogenes and food safety: Emerging listericidal technologies in the food industry

Listeria monocytogenes, a causative agent of listeriosis, is a major foodborne pathogen. Among pathogens, L. monocytogenes stands out for its unique ecological and physiological characteristics. This distinct lifestyle of L. monocytogenes has a significant impact on food safety and public health, mainly through the ability of this pathogen to multiply at refrigeration temperature and to persist in the food processing environment. Due to a combination of these characteristics and emerging trends in consumer preference for ready-to-eat and minimally processed food, there is a need to develop effective and sustainable approaches to control contamination of food products with L. monocytogenes. Implementation of an efficient and reliable control strategy for L. monocytogenes must first address the problem of cross-contamination. Besides the preventive control strategies, cross-contamination may be addressed with the introduction of emerging post packaging non-thermal or thermal hurdles that can ensure delivery of a listericidal step in a packed product without interfering with the organoleptic characteristics of a food product. This review aims to present the most relevant findings underlying the distinct lifestyle of L. monocytogenes and its impact on food safety. We also discuss emerging food decontamination technologies that can be used to better control L. monocytogenes.

Permeation of human scent through laboratory examination gloves

It is generally accepted in the canine detection industry that a barrier (such as a glove) should be used between a human and evidence or canine training aids in order to prevent contamination and cross-contamination as well as protect the handler from hazardous materials. However, no studies exist evaluating this assumption. Further, there is no published literature examining the different types of gloves for their utility in handling evidence or training materials used in canine detection work. This study was the first of its kind to address these gaps in the literature. First, GloGerm™ was used as a proxy for human scent and odor(s)/particulate(s) to visualize potential contamination. Then, three types of gloves (nitrile, two layers of nitrile, latex, and polyethylene) were tested for the permeation of human scent using furfural as a proof of concept, followed by pooled human sweat. Finally, the inherent odor of each glove type was identified. Two analytical techniques were used simultaneously as static and standoff dynamic detection systems, respectively: solid-phase microextraction-gas chromatography-mass spectrometry (SPME-GC-MS) and direct analysis in real time-mass spectrometry (DART-MS). Using a double layer of nitrile gloves was the most effective in preventing furfural permeation from the analytical standard, while a single layer of nitrile prevented furfural from permeating from human sweat up to 2 h. Polyethylene gloves allowed the highest amount of furfural permeation but had no inherent odor detected. Headspace analysis detected two compounds for nitrile gloves and four compounds for latex gloves, but the nitrile compounds had a higher relative abundance.

Evaluation of Potential Impacts of Free Chlorine during Washing of Fresh-Cut Leafy Greens on Escherichia coli O157:H7 Cross-Contamination and Risk of Illness

Addition of chlorine-based antimicrobial substances to fresh-cut leafy green wash water is done to minimize microbial cross-contamination during processing. We developed the FDA Leafy Green Risk Assessment Model (FDA-LGRAM) to quantify the impact of free chlorine concentration in wash water during fresh-cut lettuce processing on the extent of water-mediated cross-contamination between shredded lettuce and the associated risk of illness due to exposure to Escherichia coli O157:H7. At different contamination prevalence and levels of E. coli O157:H7 on incoming lettuce heads, the model compared the predicted prevalence of contaminated fresh-cut lettuce packages and the risk of illness per serving between: (1) a scenario where fresh-cut lettuce was packaged without washing; and (2) scenarios involving washing fresh-cut lettuce with different levels of free chlorine (0 ppm, 5 ppm, 10 ppm, 15 ppm, and 20 ppm) prior to packaging. Our results indicate that the free chlorine level in wash water has a substantial impact on the predicted prevalence of contaminated fresh-cut lettuce packages and the risk of illness associated with E. coli O157:H7 in fresh-cut lettuce. Results showed that the required level of free chlorine that can minimize water-mediated cross-contamination and reduce the corresponding risk of illness depended on contamination prevalence and levels of E. coli O157:H7 on incoming lettuce heads. Our model also indicated that the pathogen inactivation rate in wash water via free chlorine was a key model parameter that had a significant impact on the extent of cross-contamination during washing and the predicted associated risk of illness.

Mycobacterium bovis Bacillus Calmette-Guérin Cross-Contamination in the Operating Room: A Case Report

Mycobacterium tuberculosis complex (MTBC) false-positive cultures are commonly attributed to laboratory cross-contamination, but cross-contamination in the operating room (OR) is seldom reported. We report an investigation of cross-contamination in the OR for our case patient, who underwent surgical intervention for a chronic, left-sided breast lesion. Although the case patient had never received Mycobacterium bovis bacillus Calmette-Guérin (BCG) vaccine or chemotherapy, a subsequent surgical sample culture was identified as MTBC by high-performance liquid chromatography and M. bovis BCG-type by genotyping. A collaborative false-positive investigation was initiated, and we discovered a cross-contamination event in the OR from a source case who received BCG intravesical instillation. Clinicians, public health, and infection control staff should be aware that MTBC cross-contamination in the OR is rare, but possible, and should recognize the importance of conducting thorough false-positive investigations.

ESHRE guideline: medically assisted reproduction in patients with a viral infection/disease

STUDY QUESTION

What is the recommended management for medically assisted reproduction (MAR) in patients with a viral infection or disease, based on the best available evidence in the literature?

SUMMARY ANSWER

The ESHRE guideline on MAR in patients with a viral infection/disease makes 78 recommendations on prevention of horizontal and vertical transmission before, during and after MAR, and the impact on its outcomes, and these also include recommendations regarding laboratory safety on the processing and storage of gametes and embryos testing positive for viral infections.

WHAT IS KNOWN ALREADY

The development of new and improved anti-viral medications has resulted in improved life expectancy and quality of life for patients with viral infections/diseases. Patients of reproductive age are increasingly exploring their options for family creation.

STUDY DESIGN SIZE DURATION

The guideline was developed according to the structured methodology for the development of ESHRE guidelines. After the formulation of nine key questions for six viruses (hepatitis B virus, hepatitis C virus, human immunodeficiency virus, human papilloma virus, human T-lymphotropic virus I/II and Zika virus) by a group of experts, literature searches and assessments were performed. Papers published up to 2 November 2020 and written in English were included in the review. Evidence was analyzed by female, male or couple testing positive for the virus.

PARTICIPANTS/MATERIALS SETTING METHODS

Based on the collected evidence, recommendations were formulated and discussed until consensus was reached within the guideline group. There were 61 key questions to be answered by the guideline development group (GDG), of which 12 were answered as narrative questions and 49 as PICO (Patient, Intervention, Comparison, Outcome) questions. A stakeholder review was organized after the finalization of the draft. The final version was approved by the GDG and the ESHRE Executive Committee.

MAIN RESULTS AND THE ROLE OF CHANCE

This guideline aims to help providers meet a growing demand for guidance on the management of patients with a viral infection/disease presenting in the fertility clinic.The guideline makes 78 recommendations on prevention of viral transmission before and during MAR, and interventions to reduce/avoid vertical transmission to the newborn. Preferred MAR treatments and interventions are described together with the effect of viral infections on outcomes. The GDG formulated 44 evidence-based recommendations-of which 37 were formulated as strong recommendations and 7 as weak-33 good practice points (GPP) and one research only recommendation. Of the evidence-based recommendations, none were supported by high-quality evidence, two by moderate-quality evidence, 15 by low-quality evidence and 27 by very low-quality evidence. To support future research in the field of MAR in patients with a viral infection/disease, a list of research recommendations is provided.

LIMITATIONS REASONS FOR CAUTION

Most interventions included are not well-studied in patients with a viral infection/disease. For a large proportion of interventions, evidence was very limited and of very low quality. More evidence is required for these interventions, especially in the field of human papilloma virus (HPV). Such future studies may require the current recommendations to be revised.

WIDER IMPLICATIONS OF THE FINDINGS

The guideline provides clinicians with clear advice on best practice in MAR for patients with a viral infection/disease, based on the best evidence currently available. In addition, a list of research recommendations is provided to stimulate further studies in the field.

STUDY FUNDING/COMPETING INTERESTS

The guideline was developed and funded by ESHRE, covering expenses associated with the guideline meetings, with the literature searches and with the dissemination of the guideline. The guideline group members did not receive any financial incentives, all work was provided voluntarily. A.D. reports research fees from Ferring and Merck, consulting fees from Ferring, outside the submitted work. C.P. reports speakers fees from Merck and MSD outside the submitted work. K.T. reports speakers fees from Cooper Surgical and Ferring and consultancy fees as member of the advisory board BioTeam of Ferring, outside the submitted work. The other authors have no conflicts of interest to declare.

DISCLAIMER

This guideline represents the views of ESHRE, which were achieved after careful consideration of the scientific evidence available at the time of preparation. In the absence of scientific evidence on certain aspects, a consensus between the relevant ESHRE stakeholders has been obtained. Adherence to these clinical practice guidelines does not guarantee a successful or specific outcome, nor does it establish a standard of care. Clinical practice guidelines do not replace the need for application of clinical judgment to each individual presentation, nor variations based on locality and facility type. ESHRE makes no warranty, express or implied, regarding the clinical practice guidelines and specifically excludes any warranties of merchantability and fitness for a particular use or purpose. (Full disclaimer available at  www.eshre.eu/guidelines.).

Particle release and transport from human skin and clothing: A CFD modeling methodology

Particle release from human skin and clothing has been identified as an important contributor to particulate matter burden indoors. However, knowledge about modeling the coarse particle release from skin and clothing is limited. This study developed a new empirically validated CFD modeling methodology for particle release and transport from seated occupants in an office setting. We tested three modeling approaches for particle emissions: Uniform; Uniform + Localized; and Uniform + Localized with Body Motion; applied to four office scenarios involving a single occupant and two occupants facing each other at 1- and 2-m distances. Uniform particle emissions from skin and clothing underpredicted personal inhalation exposure by as much as 55%-80%. Combining uniform with localized emissions from the armpits drastically reduced the error margin to <10%. However, this modeling approach heavily underestimated particle mass exchange (cross-contamination) between the occupants. Accounting for the occupant's body motion-by applying the momentum theory method-yielded the most accurate personal exposure and cross-contamination results, with errors below 12%. The study suggests that for accurate modeling of particle release and transport from seated occupants indoors, localized body emissions in combination with simplified bodily movements need to be taken into account.

A silver lining in cell line authentication: Short tandem repeat analysis of 1373 cases in China from 2010 to 2019

Continuous cell lines are practical models that are widely used in the study of disease mechanisms and particularly cancers. However, the issue of cell line cross-contamination has existed since the 1960s, despite repeated advocation for cell line authentication by many experts. Furthermore, cell line abuse has been underestimated and underreported. The China Center for Type Culture Collection (CCTCC) received 1373 cell samples for authentication from 2010 to 2019, and has found that the quality of cell lines has improved during this time, offering a positive outlook for the future.

Food Safety Knowledge, Attitudes, and Practices Among Jordan Universities Students During the COVID-19 Pandemic

Objective: This study aimed to evaluate food safety knowledge, attitudes and practices (KAP) amongst university students in Jordan and changes in food-related behaviors during the COVID-19 pandemic. Correlation between food safety KAP scores and general characteristics of university students was also evaluated. Methods: A cross-sectional study was conducted where an Internet-based questionnaire was distributed through social media platforms. The sample consisted of 1,739 respondents from 29 Jordanian universities. The participants completed a 58-item questionnaire covering demographical characteristics and different food safety aspects which were namely "COVID-19 food-related attributes," "food cooking and storage," "personal hygiene." "cross-contamination prevention/disinfection procedures." and "restaurant hygiene." Descriptive statistics, Chi square tests and binary logistic analysis were used to assess the data. Results: The sample consisted of 67.2% females with a mean age of 21.3 ± 1.8 years. The average overall score of the tested aspects was 14.1/34.0 which corresponds to 41.3% of the questions being answered correctly. The percentage of correct answers of "COVID-19 food-related attributes," "food cooking and storage," "cross-contamination prevention/disinfection procedures," "personal hygiene" and "restaurant hygiene" was 56.8, 36.6, 28.4, 44.6. and 36.9%, respectively. A significant (P <0.05) association between respondents' food safety KAP scores and gender, marital status, university degree, employment status, self-rating of food safety knowledge, and the source of food safety information. Conclusion: University students in Jordan had insufficient KAP scores which is a concerning trend during the pandemic. Teaching fundamentals of food safety in the form of short courses/ lectures is recommended.

Incorporation of Antimicrobial Bio-Based Carriers onto Poly(vinyl alcohol-co-ethylene) Surface for Enhanced Antimicrobial Activity

A biobased rechargeable antimicrobial modification approach was developed using a covalent immobilization of food grade yeast cell wall particles on a model plastic film. We demonstrate the applications of this modification approach on poly(vinyl alcohol-co-ethylene) surface to inactivate inoculated bacteria with or without the presence of organic content, reducing the cross-contamination between food contact surface and model fresh produce, and inhibiting the growth of biofilms on the film surface. These biobased cell wall particle modified plastic films can enhance the binding of chlorine to the plastic surface in the form of N-halamine, extend the stability of chlorine against high organic content and ambient storage, and improve the rechargeability of the plastic films. Upon charging with chlorine, these modified plastic films inactivated 5 log of model Gram-negative bacteria (Escherichia coli O157:H7) and Gram-positive bacteria (Listeria innocua used as a surrogate of pathogenic Listeria monocytogenes) within 2 min of surface inoculation in water and within 20 min in an organic-rich aqueous environment. The modified plastic films prevented the transfer of bacteria and eliminated cross-contamination from the contaminated films to a spinach leaf surface, while 3 log CFU/leaf of bacteria were transferred from a contaminated native film to a noninoculated spinach surface. In addition, these modified plastic films reduced the adhesion of L. innocua cells by 2.7-3.6 log CFU/cm² compared with control films during extended incubation for biofilm formation. Overall, this study demonstrates the feasibility of this biobased food grade modification approach to reduce microbial contamination and improve produce safety in the food processing industry.

Development of Optimized Vitrification Procedures Using Closed Carrier System to Improve the Survival and Developmental Competence of Vitrified Mouse Oocytes

The open carrier system (OC) is used for vitrification due to its high efficiency in preserving female fertility, but concerns remain that it bears possible risks of cross-contamination. Closed carrier systems (CC) could be an alternative to the OC to increase safety. However, the viability and developmental competence of vitrified/warmed (VW) oocytes using the CC were significantly lower than with OC. We aimed to improve the efficiency of the CC. Metaphase II oocytes were collected from mice after superovulation and subjected to in vitro fertilization after vitrification/warming. Increasing the cooling/warming rate and exposure time to cryoprotectants as key parameters for the CC effectively improved the survival rate and developmental competence of VW oocytes. When all the conditions that improved the outcomes were applied to the conventional CC, hereafter named the modified vitrification/warming procedure using CC (mVW-CC), the viability and developmental competence of VW oocytes were significantly improved as compared to those of VW oocytes in the CC. Furthermore, mVW-CC increased the spindle normality of VW oocytes, as well as the cell number of blastocysts developed from VW oocytes. Collectively, our mVW-CC optimized for mouse oocytes can be utilized for humans without concerns regarding possible cross-contamination during vitrification in the future.

Development of a liquid chromatography-tandem mass spectrometry method to determine colistin, bacitracin and virginiamycin M1 at cross-contamination levels in animal feed

Cross-contamination of animal feed with antibiotics may occur during manufacturing in feed mills, because shared production lines can be used for medicated and non-medicated feed, but may also occur during transport, storage and at the farm level. This is a major issue in the current context where antimicrobial usage must be controlled in order to maintain their effectiveness. A LC-MS/MS method was developed for the determination of colistin, bacitracin A and virginiamycin M1 in feed for pigs, poultry and rabbits at concentrations similar to those encountered in cross-contamination. After investigating various issues related to colistin behaviour and matrix effects, we successfully validated this method according to the requirements of European regulations in terms of linearity, trueness, precision, limit of quantification and limit of decision. Trueness ranged 88.6-107.8% and precision ranged 12.6-21.2%. We then applied this method to the analysis of medicated pig feed to check the performance of the method on "real" samples of medicated feed. We subsequently analysed non-medicated pig, and rabbit feed samples, collected directly on farms, to check the rate of cross-contamination. No samples were contaminated by colistin, bacitracin, or virginiamycin.

Cross contamination meets misclassification: Awakening of CHP-100 from sleeping beauty sleep-A reviewed model for Ewing's sarcoma

A human cell line of neuroblastic tissue, which was believed to have been lost to science due to its unavailability in public repositories, is revived and reclassified. In the 1970s, a triple set of neuroblastoma (NB) cell lines became available for research as MYCN-amplified vs nonamplified models (CHP-126/-134 and CHP-100, respectively). Confusingly, CHP-100 was used in subsequent years as a model for NB and, since the 1990s, as a model for neuroepithelioma and later as a model for Ewing's sarcoma (ES), which inevitably led to non-reproducible results. A deposit at a bioresource center revealed that globally available stocks of CHP-100 were identical to the prominent NB cell line IMR-32 and CHP-100 was included into the list of misidentified cell lines. Now we report on the rediscovery of an authentic CHP-100 cell line and provide evidence of incorrect classification during establishment. We show that CHP-100 cells carry a t(11;22)(q24;q12) type II EWSR1-FLI1 fusion and identify it as a classic ES. Although the question of whether CHP-100 was a virtual and never existing cell line from the beginning is now clarified, the results of all relevant publications should be considered questionable. Neither the time of the cross-contamination event with IMR-32 is known nor was the final classification as a model for Ewing family of tumors available with an associated short tandem repeat profile. After a long road of errors and confusion, authentic CHP-100 is now characterized as a type II EWSR1-FLI1 fusion model 44 years after its establishment.

Comparative Analysis of Consumer Exposure to Resistant Bacteria through Chicken Meat Consumption in Germany

Human exposure to bacteria carrying antimicrobial resistance (AMR) genes through the consumption of food of animal origin is a topic which has gained increasing attention in recent years. Bacterial transmission can be enhanced, particularly in situations in which the consumer pays less attention to hygiene practices, and consumer exposure to foodborne resistant bacteria through ready-to-eat foods could be increased. It has been demonstrated that even methicillin-resistant Staphylococcus aureus (MRSA) bacteria, which have low prevalence and concentration in raw chicken meat in Germany, may reach the consumer during barbecue events after failures in hygiene practices. This study aimed to quantify the consumer exposure to extended-spectrum beta-lactamase- (ESBL) or ampicillinase class C (AmpC) beta-lactamase-producing E. coli in Germany through the consumption of chicken meat and bread during household barbecues. The study considered cross-contamination and recontamination processes from raw chicken meat by using a previously-developed probabilistic consumer exposure model. In addition, a comparative analysis of consumer exposure was carried out between ESBL-/AmpC-producing E. coli and MRSA. Our results demonstrated that the probability of ESBL-/AmpC-producing E. coli reaching the consumer was 1.85 × 10^-5 with the number of bacteria in the final serving averaging 332. Given the higher prevalence and concentration of ESBL-/AmpC-producing E. coli in raw chicken meat at retail compared to MRSA, comparative exposure assessment showed that the likelihood and extent of exposure were significantly higher for ESBL-/AmpC-producing E. coli than for MRSA. ESBL-/AmpC-producing E. coli was determined to be 7.6 times likelier (p-value < 0.01) than MRSA to reach the consumer, with five times the concentration of bacteria in the final serving (p-value < 0.01).

Dental tray adhesives and their role as potential transmission medium for microorganisms

Objectives

This study aimed to evaluate the possible ability of dental impression tray adhesives to serve as a transmission medium for bacteria and fungi when reusable adhesive applicators are utilized.

Materials and methods

Ten flasks with tray adhesive were monitored over a period of 12 weeks during clinical use for contamination with bacteria or fungi. Adhesive fluid samples were cultivated on eight different culture media. All grown colonies were identified by using mass spectrometry (MALDI‐TOF). Isolates without reliable identification were either identified by Rapid ID 32 API‐STREP V3.0 or by sequencing the 16S rRNA genes.

Results

After 4 weeks, bacterial growth was detected on chocolate blood agar plates in five different samples. The bacterial species were identified as Staphylococcus warnerii, Staphylococcus epidermidis, Staphylococcus pasteuri, Ralstonia insidiosa, and Alloiococcus otitidis. After 8 weeks Streptococcus oralis grew on a blood agar plate. In all samples, no fungi were identified.

Conclusions

The disinfectant component of the tested tray adhesive seems to be effective. However, some bacteria survived in the flask for a clinically relevant time, which might result in a potential transmission to a new host.

Recent developments in antimicrobial and antifouling coatings to reduce or prevent contamination and cross-contamination of food contact surfaces by bacteria

Illness as the result of ingesting bacterially contaminated foodstuffs represents a significant annual loss of human quality of life and economic impact globally. Significant research investment has recently been made in developing new materials that can be used to construct food contacting tools and surfaces that might minimize the risk of cross-contamination of bacteria from one food item to another. This is done to mitigate the spread of bacterial contamination and resultant foodborne illness. Internet-based literature search tools such as Web of Science, Google Scholar, and Scopus were utilized to investigate publishing trends within the last 10 years related to the development of antimicrobial and antifouling surfaces with potential use in food processing applications. Technologies investigated were categorized into four major groups: antimicrobial agent-releasing coatings, contact-based antimicrobial coatings, superhydrophobic antifouling coatings, and repulsion-based antifouling coatings. The advantages for each group and technical challenges remaining before wide-scale implementation were compared. A diverse array of emerging antimicrobial and antifouling technologies were identified, designed to suit a wide range of food contact applications. Although each poses distinct and promising advantages, significant further research investment will likely be required to reliably produce effective materials economically and safely enough to equip large-scale operations such as farms, food processing facilities, and kitchens.

Metagenomic Analysis of Microbial Composition Revealed Cross-Contamination Pathway of Bacteria at a Foodservice Facility

Bacterial contamination of food-contact surfaces can be a potential risk factor for food quality and safety. To evaluate the spatial and temporal variations of the potential cross-contamination routes, we conducted a biogeographical assessment of bacteria in a foodservice facility based on the diversity of microflora on each surface. To this end, we performed high-throughput amplicon sequencing of 13 food-contact and non-food contact surfaces in a foodservice facility throughout a year. The results showed that Bacillus, Acinetobacter, Streptophyta, Enterobacter, Pseudomonas, Serratia, Enhydrobacter, Staphylococcus, Paracoccus, and Lysinibacillus were the dominant genera found on the kitchen surfaces of the foodservice facility. Depending on the season, changes in Firmicute/Proteobacteria ratios were observed, and the fan becomes the main source of outdoor air contamination. The microbial flow associated with spoilage was also observed throughout food preparation. Taken together, our results would be a powerful reference to hygiene managers for improvement of food processes.

Effect of Chlorine Dioxide Treatment on Human Pathogens on Iceberg Lettuce

In the vegetable processing industry, the application of chlorine dioxide (ClO2) as a disinfectant solved in washing water to eliminate undesirable microorganisms harmful to consumers' health and the shelf life of produce has been discussed for years. The disinfection efficacy depends on various factors, e.g., the location of microorganisms and the organic load of the washing water. The present study analyzed the sanitation efficacy of various concentrations of water-solved ClO2 (cClO2: 20 and 30 mg L-1) on Escherichia coli (1.1 × 104 cfu mL-1), Salmonella enterica (2.0 × 104 cfu mL-1) and Listeria monocytogenes (1.7 × 105 cfu mL-1) loads, located on the leaf surface of iceberg lettuce assigned for fresh-cut salads. In addition, it examined the potential of ClO2 to prevent the cross-contamination of these microbes in lettuce washing water containing a chemical oxygen demand (COD) content of 350 mg L-1 after practice-relevant washing times of 1 and 2 min. On iceberg leaves, washing with 30 mg L-1 ClO2 pronouncedly (1 log) reduced loads of E. coli and S. enterica, while it only insignificantly (<0.5 × log) diminished the loads of L. monocytogenes, irrespective of the ClO2 concentration used. Although the sanitation efficacy of ClO2 washing was only limited, the addition of ClO2 to the washing water avoided cross-contamination even at high organic loads. Thus, the application of ClO2 to the lettuce washing water can improve product quality and consumer safety.

Impact of a Whole-Room Atomizing Disinfection System on Healthcare Surface Contamination, Pathogen Transfer, and Labor Efficiency

Supplemental Digital Content is available in the text.

Healthcare surfaces contribute to nosocomial disease transmission. Studies show that despite standard guidelines and practices for cleaning and disinfection, secondary infection spread among healthcare workers and patients is common in ICUs. Manual terminal cleaning practices in healthcare are subject to highly variable results due to differences in training, compliance, and other inherent complexities. Standard cleaning practices combined with no-touch disinfecting technologies, however, may significantly lower nosocomial infection rates. The objective of this study was to evaluate the efficacy of a whole-room, no-touch disinfection intervention to reduce the concentration and cross-contamination of surface bacteria when used in tandem with manual cleaning protocols.

Dental Emergencies Management in COVID-19 Pandemic Peak: A Cohort Study

Due to the global coronavirus disease 2019 pandemic, the high risk of cross-contamination and the overload of hospital facilities have resulted in a real urgency for restricting dental emergency patient flow. In this context, the objectives of the current work were to 1) measure the ability of a triage-based management strategy to limit patient admission and 2) evaluate the success rate of both on-site and remote emergency management regarding symptom relief and pain control over a 1-mo period. We included all patients contacting the dental medicine department for an emergency consultation during the lockdown, between April 1 and April 30, 2020 (N = 570). Following a telephone consultation and based on preestablished admission guidelines, a decision was made at baseline (T0) to either admit the patient for treatment or perform remote management by providing advice and/or drug prescription. Patients were then followed up systematically at 1 wk and 1 mo. Management failure was defined as the need for emergency admission for patients managed remotely since T0 and for new emergency admission for those admitted at T0. The global follow-up rate of patients with a complete data set was 91.4% (N = 521). Of included patients, 49.3% could be managed without admission for emergency reasons for 1 mo. The proportion of successful management was 71.8% and 90.2% at 1 mo for remote and on-site management, respectively. To conclude, the proposed triage-based emergency management strategy with systematic follow-up was a good compromise between limiting patient admission and ensuring effective symptom relief and pain control. The strategy can be useful in situations where regulation of the emergency patient flow is required.

The Potential Use of Hypochlorous Acid and a Smart Prefabricated Sanitising Chamber to Reduce Occupation-Related COVID-19 Exposure

This work is part of a project on the development of a smart prefabricated sanitising chamber (SPSC) to provide extra measures against the transmission of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Stabilised hypochlorous acid (HOCl) is an approved disinfectant against SARS-CoV-2 by the Environmental Protection Association US in its liquid form on non-porous surfaces. This review is extended to cover its viricidal/bactericidal efficacy in aerosolised or sprayed form which showed an effective dose of as low as 20 ppm and the exposure duration of at least 60 s. The aerosolised application was also recommended with particle size of less than 200 μm to increase the contact with pathogens. The review also includes the safety and toxicity of HOCl with different concentrations. The review calls for more investigations into the effect of HOCl in mist and fog form on the respiratory system when transitioning through the proposed SPSC.

Could the ductless personalized ventilation be an alternative to the regular ducted personalized ventilation?

This study investigates the performance of two systems: personalized ventilation (PV) and ductless personalized ventilation (DPV). Even though the literature indicates a compelling performance of PV, it is not often used in practice due to its impracticality. Therefore, the present study assesses the possibility of replacing the inflexible PV with DPV in office rooms equipped with displacement ventilation (DV) in the summer season. Numerical simulations were utilized to evaluate the inhaled concentration of pollutants when PV and DPV are used. The systems were compared in a simulated office with two occupants: a susceptible occupant and a source occupant. Three types of pollution were simulated: exhaled infectious air, dermally emitted contamination, and room contamination from a passive source. Results indicated that PV improved the inhaled air quality regardless of the location of the pollution source; a higher PV supply flow rate positively impacted the inhaled air quality. Contrarily, the performance of DPV was highly sensitive to the source location and the personalized flow rate. A higher DPV flow rate tends to decrease the inhaled air quality due to increased mixing of pollutants in the room. Moreover, both systems achieved better results when the personalized system of the source occupant was switched off.

Dental care during the Covid-19 pandemic - To treat or not to treat?

The recent spread of COVID-19 presents a huge public health concern. Clinical presentations of COVID-19 range from asymptomatic cases to severe pneumonia that can lead to death. Drastic measures were necessary to prevent the disease from spreading and protect the most vulnerable groups in the general population. The rapid reorganization of the healthcare system and great efforts made by medical staff were needed to admit to hospitals and then treat a progressively growing number of patients. The predominant route of virus transmission is through direct contact with an infected individual or respiratory droplets, therefore, all dental procedures with aerosol-formation pose an extremely high risk for the spread of infection. The aim of this article is to provide an overview of the current epidemiological situation, routes of transmission, and specific recommendations for dental practices including patient screening and triage, infection control, and treatment protocols. In this situation, it is essential that all dental healthcare workers make wise clinical decisions and educate themselves and their patients on how to prevent the spread of infection.

Complex Internal Microstructure of Feather Follicles on Chicken Skin Promotes the Bacterial Cross-Contamination of Carcasses During the Slaughtering Process

Chicken skin is considered the most susceptible to bacterial contamination during slaughter. It is rich in bushy feather follicles with complex internal structures that can absorb bacteria via cross-contamination during slaughter. Until now, the microstructural changes and local bacterial composition of feather follicles during slaughter have not been thoroughly investigated. This study used hematoxylin-eosin (HE) staining of the tissue paraffin section to investigate the structure of the feather follicles on chicken skin. In addition, the biopsy sampling method was employed for the high-throughput sequencing of 16S RNA genes to study the composition and source of bacterial contamination during slaughter. The results show that the feather follicles on chicken skin form a closed cavity structure during the slaughtering process. The volume of the irregular follicle cavity was about Ø: 200 μm × D: 1040 μm, which provides a place for the bacteria to absorb and resist the cleaning and disinfection during the slaughtering process. The composition of bacteria in the feather follicle was mainly Acinetobacter (37%), Psychrobacter (8%), Macrococcus (5%), and Comamonas (2%). The heat map obtained via the species abundance analysis of the feather follicle samples as well as the slaughter environment samples suggests that the gastrointestinal feces contaminated the feather follicles on the chicken skin mainly during the evisceration, defeathering, and chilling processes, and the last-stage chilling water also caused severe cross-contamination to the feather follicles during the chilling process.

Characterization of Salmonella Resistome and Plasmidome in Pork Production System in Jiangsu, China

The prevalence of antimicrobial resistance in zoonotic Salmonella is a significant ongoing concern over the world. Several reports have investigated the prevalence of Salmonella infections in the farm animals in China; however, there is only limited knowledge about the Salmonella cross-contamination in the slaughterhouses. Moreover, the application of genomic approaches for understanding the cross-contamination in the food-animal slaughterhouses is still in its infancy in China. In the present study, we have isolated 105 Salmonella strains from pig carcasses and environment samples collected from four independent slaughterhouses in Jiangsu, China. All the Salmonella isolates were subjected to whole genome sequencing, bioinformatics analysis for serovar predictions, multi-locus sequence types, antimicrobial resistance genes, and plasmid types by using the in-house Galaxy platform. The antimicrobial resistance of Salmonella isolates was determined using a minimal inhibitory concentration assay with 14 antimicrobials. We found that the predominant serovar and serogroup was S. Derby and O:4(B), with a prevalence of 41.9 and 55%, respectively. All the isolates were multidrug-resistant and the highest resistance was observed against antimicrobials tetracycline (95.4%) and trimethoprim and sulfamethoxazole (90.9%). Additionally, the colistin-resistant determinant mcr-1 gene was detected in five (4.8%) strains. Our study demonstrated the prevalence of antimicrobial resistance in Salmonella strains isolated from pig slaughterhouses in China and suggested that the genomic platform can serve as routine surveillance along with the food-chain investigation.

Patients With COVID-19 Undergoing Cesarean Deliveries: Adapting the OR Suite and Perioperative Care to Prevent Transmission

The novel coronavirus SARS-CoV-2 first appeared in Wuhan, China, in December 2019 and led to the Coronavirus Disease 2019 (COVID-19), which quickly spread globally. Protocols for surgical patients with COVID-19 were lacking, particularly for pregnant women undergoing cesarean deliveries. Perioperative nurses at Tongji Hospital in Wuhan retrospectively analyzed the perioperative nursing process, including OR preparation, intraoperative care, and OR cleanup, for women with COVID-19 undergoing cesarean deliveries. Preparation involved altering the layout of the surgical suite, educating staff members, providing personal protective equipment, and creating new in-house guidelines to help protect personnel and patients. This article describes how perioperative personnel strategized to prevent the transmission of COVID-19 in the OR and presents a multiple-case summary of six pregnant patients with COVID-19 who underwent cesarean deliveries at Tongji Hospital in January and February 2020.

Control of Antimicrobials in Feed Using Liquid Chromatography-Tandem Mass Spectrometry: Assessment of Cross-Contamination Rates at the Farm Level

Antimicrobial cross-contamination of animal feed may occur during feed manufacturing, because shared production lines can be used for the production of medicated and nonmedicated feeds, and also during feed transport, storage at the farm level, and usage. This is a major issue in the current context in which antimicrobial usage must be controlled to maintain their effectiveness. The purpose of this study was to assess the antimicrobial cross-contamination rate of feed at the farm level. Here, we optimized a liquid chromatography-tandem mass spectrometry method for the determination of 11 antimicrobials in feed for pigs, poultry, and rabbits, which were strategically chosen. The method was validated according to European regulations in terms of mass spectrometry identification criteria and quantification criteria (linearity, trueness, precision, limit of quantification, and limit of decision). The results were in compliance with these regulations except for doxycycline, which may be quantified with higher uncertainty. This method was applied to the analysis of 192 nonmedicated pig, poultry, and rabbit feed samples that were collected directly from farms to assess antimicrobials animal exposure. Cross-contamination rates were relatively high with 44% of the samples being contaminated at a concentration above the quantification limit of 0.125 mg/kg and 15% of the samples being contaminated above 1 mg/kg. This result suggests that the current regulations and feed processing recommendations need to be improved, taking into account the risks arising from these contaminations.

High Occurrence of Multiresistant Salmonella Infantis in Retail Meat in Ecuador

Salmonella enterica is among the most important foodborne pathogens. In Ecuador, there is limited information about non-typhoidal S. enterica occurrence in raw meats, its serotype distribution, and antimicrobial resistance. In this study, we addressed this issue in 1095 retail fresh meats (chicken, pork, veal, lamb, beef, and turkey) in Quito by performing a traditional culture methodology and molecular detection. We found that S. enterica was present in 38.1% of the samples, and Salmonella Infantis was the most common serotype showing a high antibiotic resistance and a wide host range. Some host-adapted serotypes were found in uncommon sources of meat, suggesting cross-contamination and the need to implement good manufacturing practices in meat processing. High levels of multidrug resistance were found in all serotypes. There is an urgent need to identify Salmonella serotypes in food to compare with clinical data and to carry out epidemiological studies to control and prevent outbreaks and infections.

Microbial Cross-contamination in Multidose Eyedrops: The Impact of Instillation Angle and Bottle Geometry

Purpose

To evaluate the impact of instillation angle and nozzle tip geometry on cross-contamination risk of multidose ocular solution bottles.

Methods

Pseudomonas aeruginosa solution was passed exclusively on the outside of the nozzle to simulate contamination on the exterior of topical agents. Three drops were administered from angles of 90° and 45° from bottles with either a round or sharp tip geometry, and the cultures were examined for growth. Two-hundred sixteen cultures from nine lubricant eyedrop brands currently existing in the Brazilian market were assessed for bacterial growth.

Results

After seven days, bacterial contamination was detected in 53.7% of cultures when drops were administered at 90° and in 70.4% of cultures at 45°. Eyedrops collected from a rounded nozzle tip and an instillation angle of 90° transmitted bacteria in 69.4% of cases, whereas those administered from a sharp tip transmitted bacteria in only 22.2% of cases (P = 0.001). At an instillation angle of 45°, contamination was identified in 83.3% of bottles with a rounded tip geometry and in only eight of 18 bottles (44.4%) from those with a sharp nozzle geometry (P = 0.005).

Conclusions

Adjusting the instillation angle of eyedrop solutions to 90°, as well as using a nozzle geometry that prevents flow of the solution to the side of the bottle, significantly reduced contamination rates.

Translational Relevance

Standardizing drop bottles and adjusting delivery angle shows promise in reducing contamination rates and may critically impact the quality of care for patients requiring topical therapeutic agents.

An Italian survey of undeclared allergens in food over the years 2014-2018

Large population studies estimated that the frequency of food allergies is increasing worldwide. In the last two decades, a 'second wave' of the allergy epidemic has emerged as a growing public health problem. EU regulation strengthened information to consumers about allergens in pre-packed food, since December 2014 it has been extended to non-prepacked foods by the Regulation (EU) No 1169/2011 of the European Commission. The present work aims to present a five-year survey on the presence of nine types of allergen in several foods, including food of animal origin and baby food. The concentration found for each irregular allergen is generally low, but some samples with no gluten indication contained a concentration above 10 mg kg^-1 with the highest value of 138.5 mg kg^-1 in a dietetic food, during the screening in 2017. These data underline the importance and the necessity of a complete food labelling to protect the majority of allergic individuals.

Fate of Listeria monocytogenes in the Presence of Resident Cheese Microbiota on Common Packaging Materials

Literature data regarding the survival of microorganisms on materials used for food package purposes are scarce. The aim of the current study is to assess the survival of Listeria monocytogenes on different packaging materials for dairy products during extended storage at different temperatures. Three packaging materials (5 × 5 cm) were contaminated with a cocktail of five strains of Listeria monocytogenes suspended in a cheese homogenate, including the cheese's native microbial population. Contaminated samples were incubated at 37°, 12°, and 4°C and periodically analyzed up to 56 days. The evolution of the total viable count and pathogen population was evaluated. At 37°C, the results showed that Listeria monocytogenes was no longer detected on polyethylene-coated nylon (B) by day 4 and on polyethylene-coated parchment (A) and greaseproof paper (C) by day 7. Interestingly, the initial cell population (ranging between 2.5 and 2.7 log CFU/cm2) of Listeria monocytogenes increased to 3 log CFU/cm2 within 4 days of storage at 12°C on A and C. During storage, the number remained fairly constant at 12°C and 4°C on two materials (A-C) and decreased slowly on the third one (B). This study shows that survival of Listeria monocytogenes on packaging materials for dairy products will be higher when stored at 4 or 12°C compared to 37°C. The survival of Listeria monocytogenes on the packaging materials raises concerns of cross-contamination during food handling and preparation at catering and retail premises and within the home, highlighting the importance of treating the packaging materials as a potential source of cross-contamination. These initial findings may aid in quantifying risks associated with contamination of food packaging materials.

Appearance of Thiacloprid in the Guttation Liquid of Coated Maize Seeds

Thiacloprid (TCL) uptake by maize plants that emerge from coated seeds has been investigated and characterized via measurements of the compound in the guttation liquid. TCL levels were determined in the guttation liquid: (a) under field and semi-field conditions, (b) for different maize varieties, (c) applying different dosages, and (d) as affected by cross-contamination between maize seeds via soil. Cross-contamination was described by uptake interactions between seeds coated with TCL and neighboring seeds not coated or coated with other neonicotinoids, e.g., either thiamethoxam (TMX) or clothianidin (CLO). TCL levels remained under 100 µg/mL in the guttation liquid under field conditions, and were quantifiable even on the 39th day after planting of coated seeds. Higher levels up to 188.6 µg/mL were detected in plants grown under semi-field conditions in pots. Levels in the guttation liquid were also found to be influenced by the applied dosages. The uptake of TCL was found to vary for different maize varieties. Appearance of TCL as a cross-contaminant in the guttation liquid of neighboring plants emerging from non-coated maize seeds indicates translocation of the compound via soil. Peak levels of TCL cross-contamination were found to be lower (43.6 µg/mL) than the corresponding levels in the parent maize plants emerging from coated seeds (107.5 µg/mL), but values converge to each other. Similar trends were observed with neighboring seeds coated with other neonicotinoids (TMX or CLO). The translocation rate of TCL and its uptake by other plants seem to be lower than that of TMX or CLO.

CUT-LAMP: Contamination-Free Loop-Mediated Isothermal Amplification Based on the CRISPR/Cas9 Cleavage

Loop-mediated isothermal amplification (LAMP) is a sensitive and widely used gene amplification technique. However, high amplification efficiency and amplification products containing multiple inverted repeats make the LAMP reaction extremely vulnerable to false-positive amplification caused by contamination. Herein, a contamination-free LAMP (CUT-LAMP) assisted by the CRISPR/Cas9 cleavage with superior reliability and durability has been reported. The core of CUT-LAMP is the engineering of the forward or backward inner primer in the target-independent region, which makes the LAMP products contain a protospacer adjacent motif (PAM) site for the CRISPR/Cas9 recognition. For the CUT-LAMP reaction, cross-contamination can be efficiently cleaved by the corresponding Cas9/sgRNA, but the target gene can get rid of digestion due to the lack of a PAM site near the recognition region. CUT-LAMP shows impressive contamination resistance but does not significantly increase procedure complexity; thus, it represents a simple and versatile toolkit facilitating the adoption by open- and closed-tube detection format.