Efficacy of Instant Hand Sanitizers against Foodborne Pathogens Compared with Hand Washing with Soap and Water in Food Preparation Settings: A Systematic Review

Efficacy of a New Alcohol-Free Organic Acid-Based Hand Sanitizer against Foodborne Pathogens

In light of the global health crisis triggered by the COVID-19 pandemic, numerous experts have deemed the utilization of hand sanitizers imperative as a precautionary measure against the virus. Consequently, the demand for hand sanitizers has experienced a substantial surge. Since the beginning of 2020, the utilization of alcohol-free hand sanitizers has been increasingly favored due to the potential risks associated with alcohol poisoning, flammability, as well as the adverse effects on skin lipid dissolution, dehydration, and sebum reduction, which can lead to severe cases of eczema and norovirus infections. In this study, we developed an aqueous hand sanitizer that does not contain alcohol. The sanitizer consists of naturally occurring, food-grade organic acids, including lactic, citric, and azelaic acids. Additionally, food-grade ammonium sulfate and a small amount of povidone-iodine (PVPI) were included in the formulation to create a synergistic and potent antibacterial effect. The effectiveness of the hand sanitizer was evaluated against four common foodborne pathogens, namely Clostridium botulinum, Escherichia coli, Listeria monocytogenes, and Staphylococcus aureus, via in vitro testing. The organic acids exhibited a synergistic inhibitory function, resulting in a 3-log reduction in CFU/mL. Furthermore, the presence of povidone-iodine and ammonium sulfate enhanced their antibacterial effect, leading to a 4-log reduction in CFU/mL. The hand sanitizer solution remained stable even after 60 days of storage. During this period, the detection of additional triiodide (I3-) ions occurred, which have the ability to release broad-spectrum molecular iodine upon penetrating the cell walls. This alcohol-free hand sanitizer may offer extended protection and is anticipated to be gentle on the skin. This is attributed to the presence of citric and lactic acids, which possess cosmetic properties that soften and smoothen the skin, along with antioxidant properties.

Effect of Drinking Water Salt Content on the Interaction between Surfactants and Bacteria

Sodium dodecyl sulfate (SDS) is a common surfactant used in various hygienic products. Its interactions with bacteria were studied previously, but the three-way interaction between surfactants, bacteria, and dissolved salts in the context of bacterial adhesion has not been studied. Here, we examined the combined effects of SDS (at concentrations typical of everyday hygienic activities) and salts, sodium chloride, and calcium chloride (at concentrations typically found in tap water) on the adhesion behavior of the common opportunistic pathogen Pseudomonas aeruginosa. We found that bacterial adhesion in the absence of SDS was dependent on the cation concentration rather than the total ionic strength and that combined treatment with several millimolar NaCl and SDS can increase bacterial adhesion. The addition of low concentrations of SDS (2 mM) to tens to hundreds millimolar concentrations of NaCl, typical of systems that suffer seawater incursion, reduced bacterial adhesion dramatically. Combined treatment with Ca+2 (in concentrations typical of those found in hard water) and SDS produced a small increase in total adhesion but a dramatic increase in the strength of adhesion. We conclude that the type and concentration of salts in water can have a considerable effect on the efficacy of soap in reducing bacterial adhesion and should be taken under consideration in critical applications. IMPORTANCE Surface-adhering bacteria are a reoccurring problem in many settings, including households, municipal water systems, food production facilities, and hospitals. Surfactants, and specifically sodium dodecyl sulfate (also known as SDS/SLS), are commonly used to remove bacterial contamination, but data regarding the interaction of SDS with bacteria and especially the effects of water-dissolved salts on this interaction are lacking. Here, we show that calcium and sodium ions can dramatically affect the efficacy of SDS on bacterial adhesion behavior and conclude that salt concentrations and ion species in the water supply should be considered in SDS applications.

Hand Sanitizer Gels: Classification, Challenges, and the Future of Multipurpose Hand Hygiene Products

Hand hygiene is a crucial measure in the prevention and control of infections, and there is a growing awareness among individuals who are making a conscious effort to maintain hand cleanliness. With the advent of the SARS-CoV-2 outbreak, the demand for hand hygiene products has also gradually shifted towards those with antimicrobial properties. Among these products, hand sanitizer gels (HSGs) have gained considerable popularity as an efficient method of hand cleaning, due to their rapid drying and sustained antimicrobial efficacy. Concurrently, there has been a growing interest in novel HSGs that offer additional functions such as skin whitening, moisturizing, and anti-inflammatory effects. These novel HSGs effectively address concerns associated with the ingestion of antimicrobial ingredients and demonstrate reduced skin irritation, thereby alleviating hand dermatological issues. This review provides an extensive overview of the application scenarios, classification, and challenges associated with HSGs while emphasizing the emergence of novel components with biological functions, aiming to contribute to the advancement of hand hygiene practices and offer novel insights for the development of novel HSGs with outstanding antimicrobial properties with other multiple biological functions and desirable biosafety profiles.

Impact on S. aureus and E. coli Membranes of Treatment with Chlorhexidine and Alcohol Solutions: Insights from Molecular Simulations and Nuclear Magnetic Resonance

Membranes form the first line of defence of bacteria against potentially harmful molecules in the surrounding environment. Understanding the protective properties of these membranes represents an important step towards development of targeted anti-bacterial agents such as sanitizers. Use of propanol, isopropanol and chlorhexidine can significantly decrease the threat imposed by bacteria in the face of growing anti-bacterial resistance via mechanisms that include membrane disruption. Here we have employed molecular dynamics simulations and nuclear magnetic resonance to explore the impact of chlorhexidine and alcohol on the S. aureus cell membrane, as well as the E. coli inner and outer membranes. We identify how sanitizer components partition into these bacterial membranes, and show that chlorhexidine is instrumental in this process.

Assessment of the effect of hand dryers used in shopping malls on hand hygiene

BACKGROUND

Hand drying is one of the most important factors affect hand hygiene. This study was conducted to investigate the effect of hand dryers used in the restrooms located on the food court floors in shopping malls in Turkey on hand hygiene.

METHODS

Hands were washed for at least 20 seconds by following hygienic hand washing procedures of the World Health Organization. Swab samples were taken from the wet hands after hand washing, then from the dry hands, which were dried under the hand dryers and from the air blowing part of the hand dryers. Samples were cultured on agar plates that were directly exposed to the air-blowing part of the hand dryers.

RESULTS

It was found that total coliform bacteria were 0.000 colony-forming unit (CFU)/petri in wet and dried hand, 3.437 CFU/petri in blown air and 5.250 CFU/petri in swab samples. Staphylococcus aureus was found to be 0.125, 64.125, 26.375, and 388.750 CFU/petri, respectively. Total bacteria count was found to be 0.687, 48.750, 35.625, and 595.000 CFU/petri, respectively. S. aureus and the total bacterial load were higher in the blower outlet of the hand dryers than washed hand, blown air and dried hand (P < .05). The bacteria count in the unfiltered hand dryers was higher than that in the filtered hand dryers (P < .05).

CONCLUSIONS

Using hand dryers would negatively affect hand hygiene even if hands were washed following hygienic hand washing procedures.

Association between years with incidence of communicable diseases focused on COVID-19 and hand hygiene among adults in South Korea: a cross-sectional study

Background

Handwashing is important considering the impact of communicable diseases on the public. We aimed to identify the association between years with incidence of communicable diseases during the coronavirus disease 2019 (COVID-19) pandemic and hand hygiene in South Korea.

Methods

This cross-sectional study evaluated 5 years (2013, 2015, 2017, 2019, and 2020) of data from the Korea Community Health Survey and included 1,034,422 adults. Multinomial logistic regression analysis was performed to assess handwashing frequency by year. Receiver operating characteristic analysis was used to determine the cut-off point for handwashing frequency.

Results

The always/frequently handwashing rate was 44.7%. This tendency was stronger in adults with each ascending year, with reference to 2013 (2015, odds ratio [OR] = 1.10, 95% confidence interval [CI] = 1.08, 1.13; 2017, OR = 1.10, 95% CI = 1.08, 1.13; 2019, OR = 1.17, 95% CI = 1.14, 1.20; 2020, OR = 3.21, 95% CI = 3.14, 3.29). Among women, the OR of frequently/always handwashing was 3.55 times higher (95% CI = 3.45, 3.66) in 2020 than in 2013. This OR was 2.95 among men (95% CI = 2.86, 3.04). In influenza-vaccinated participants, the OR of frequent/always handwashing was 3.25 times higher in 2020 than in 2013 (95% CI = 3.15, 3.36), while in non-vaccinated participants it was 3.17 (95% CI = 3.08, 3.27). Among adults who practiced physical distancing during the COVID-19 pandemic, the OR was 1.36 times higher (95% CI = 1.29, 1.42) with frequent handwashing, 1.64 times higher (95% CI = 1.57, 1.70) than those who did not practice it.

Conclusions

There was a strong tendency toward frequent handwashing over the years; the trend was even greater in 2020 during the COVID-19 pandemic. Given that communicable diseases and handwashing are closely related, it is necessary to promote hand hygiene for prevention.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-022-13951-x.

A case study of food handler hand hygiene compliance in high-care and high-risk food manufacturing environments using covert-observation

Observation of behaviour is superior to cognitive data, which does not equate to behaviour. Covert-observation is seldom used in food manufacturing to assess behaviour. In this case study, closed-circuit-television footage (15 h) in a business were reviewed to assess hand hygiene compliance using an electronic-checklist. Hand hygiene attempts were observed prior to entering high-risk (cake/pie)(n= 47) and high-care (sandwich/salad)(n= 153) production areas. Business hand hygiene protocol required handwashing durations ≥ 20 s. Observed durations ranged 1-71 s, <96% of attempts were <20 s. Significantly longer durations were observed when food handlers were in the presence of others (12 s) than when alone (9 s). Although <99% utilised soap, only 56-69% wetted hands first. Failure to rub all parts of hands was commonplace (<87%) and 24-35% failed to apply sanitiser after drying. Consequently, >98% of observed attempts before entering production areas did not comply with the protocol. Observed non-compliant practices may have implications for food safety in manufacturing.

Hand sanitizers as a preventive measure in COVID-19 pandemic, its characteristics, and harmful effects: a review

Background

In the global health emergency caused by COVID-19, multiple experts have mandated the use of hand sanitizers as a safety measure from COVID-19. The sale of hand sanitizers has increased many folds. Therefore, when there is such large use of hand sanitizers, it becomes extremely important to study and understand hand sanitizers in a comprehensive manner.

Main body of the abstract

This article starts with the importance of sanitizers as a defence mechanism that is employed by the hand to fight against the coronavirus. This article provides information about history, types, composition, various dosage forms, and marketed formulations of hand sanitizers. The article sheds a detailed light on industrial production techniques for hand sanitizers and also outlines new innovative techniques that were employed by the industry to mass produce hand sanitizers in the wake of the pandemic. The article further dives into a comparison between hand sanitizers and soaps so as to give pros and cons of the use of soap against the use of hand sanitizers. One of the aims of the article is to study the side effects of sanitizers so as to develop a cautious approach while using hand sanitizers and therefore a comprehensive list of side effects of the use of hand sanitizers is given.

Conclusion

The review article finds that hand sanitizers are extremely efficient in fight the virus but along with it, it brings along arrange of risks which are outlined in the article.

Alcohol-Based Sanitizers: An Effective Means for Preventing the Spread of Contagious Viral Diseases Including COVID-19

The global community is struggling with the highly contagious COVID-19. Returning to \normal life" now poses risks, and the use of appropriate protective measures has become necessary to continue daily life and protect public health. The main protective measures to prevent transmission of COVID-19 are masks, soaps and disinfectants. Because coronavirus is a \lipid-enveloped virus", it is very sensitive to lipid-dissolving chemicals and can therefore be effectively removed by washing hands sufficiently with soap and water. However, using an alcohol-based disinfectant is a more viable option for outdoor use. Alcohol-based disinfectants are inexpensive, immediately effective, easy to use and better tolerated by the skin compared to other disinfectants. WHO recommends disinfectants containing 75% isopropanol or 80% ethanol as highly effective in inactivating the SARS-CoV-2-virus. The current review discusses the role of alcohol-based hand sanitizers (ABHS) in preventing the spread of viruses, their side effects on human health, and suggests the use of alcohol-based sanitizers as potentially effective in combating the current epidemic.

Environmental impact of increased soap consumption during COVID-19 pandemic: Biodegradable soap production and sustainable packaging

A year into the coronavirus disease 2019 pandemic, the role of washing hands with soap and hand disinfectants is unavoidable as a primary way to control the infection spread in communities and healthcare facilities. The extraordinary surge in demand for handwashing products has led to environmental concerns. Since soaps are complex mixtures of toxic and persistent active ingredients, the prudent option is to promote eco-friendly replacements for the current products. On the other hand, with the increase in soap packaging waste production, soap packaging waste management and recycling become essential to reduce environmental impact. This systematic review aimed to collect some recent methods for identifying biodegradable and sustainable raw materials to produce and package cleaning agents, especially soap.

Food Safety and Employee Health Implications of COVID-19: A Review

The COVID-19 pandemic has greatly impacted the U.S. food supply and consumer behavior. Food production and processing are being disrupted as illnesses, proactive quarantines, and government-mandated movement restrictions cause labor shortages. In this environment, the food industry has been required to adopt new, additional practices to minimize the risk of COVID-19 cases and outbreaks among its workforce. Successfully overcoming these challenges requires a comprehensive approach that addresses COVID-19 transmission both within and outside the facility. Possible interventions include strategies (i) to vaccinate employees, (ii) to assure that employees practice social distancing, (iii) to assure that employees wear face coverings, (iv) to screen employees for COVID-19, (v) to assure that employees practice frequent hand washing and avoid touching their faces, (vi) to clean frequently touched surfaces, and (vii) to assure proper ventilation. Compliance with these control strategies must be verified, and an overall COVID-19 control culture must be established to implement an effective program. Despite some public misperceptions about the health risk of severe acute respiratory syndrome coronavirus 2 on foods or food packaging, both the virus biology and epidemiological data clearly support a negligible risk of COVID-19 transmission through food and food packing. However, COVID-19 pandemic-related supply chain and workforce disruptions and the shift in resources to protect food industry employees from COVID-19 may increase the actual food safety risks. The goal of this review was to describe the COVID-19 mitigation practices adopted by the food industry and the potential impact of these practices and COVID-19-related disruptions on the industry's food safety mission. A review of these impacts is necessary to ensure that the food industry is prepared to maintain a safe and nutritious food supply in the face of future global disruptions.

Soap, water, and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2): an ancient handwashing strategy for preventing dissemination of a novel virus

Public Health Agencies worldwide (World Health Organization, United States Centers for Disease Prevention & Control, Chinese Center for Disease Control and Prevention, European Centre for Disease Prevention and Control, etc.) are recommending hand washing with soap and water for preventing the dissemination of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections. In this review, we have discussed the mechanisms of decontamination by soap and water (involving both removal and inactivation), described the contribution of the various components of formulated soaps to performance as cleansers and to pathogen inactivation, explained why adherence to recommended contact times is critical, evaluated the possible contribution of water temperature to inactivation, discussed the advantages of antimicrobial soaps vs. basic soaps, discussed the differences between use of soap and water vs. alcohol-based hand sanitizers for hand decontamination, and evaluated the limitations and advantages of different methods of drying hands following washing. While the paper emphasizes data applicable to SARS-CoV-2, the topics discussed are germane to most emerging and re-emerging enveloped and non-enveloped viruses and many other pathogen types.

Coronavirus Disease 2019 (COVID-19) Crisis Measures: Health Protective Properties?

The ongoing 2019 coronavirus disease (COVID-19) crisis has led governments to impose measures including mask wearing, physical distancing, and increased hygiene and disinfection, combined with home confinement and economic shutdown. Such measures have heavy negative consequences both on public health and the economy. However, these same measures have positive outcomes as "side effects" that are worth mentioning since they contribute to the improvement of some aspects of the population health. For instance, mask wearing helps to reduce allergies as well as the transmission of other airborne disease-causing pathogens. Physical distancing and social contact limitation help limit the spread of communicable diseases, and economic shutdown can reduce pollution and the health problems related to it. Decision makers could get inspired by these positive "side effects" to tackle and prevent diseases like allergies, infectious diseases and noncommunicable diseases, and improve health care and pathology management. Indeed, the effectiveness of such measures in tackling certain health problems encourages inspiration from COVID-19 measures towards managing selected health problems. However, with the massive damage COVID-19-related measures have caused to countries' economies and people's lives, the question of how to balance the advantages and disadvantages of these measures in order to further optimize them needs to be debated among health care professionals and decision makers.

Scientific Evidence Supports the Use of Alcohol-Based Hand Sanitizers as an Effective Alternative to Hand Washing in Retail Food and Food Service Settings When Heavy Soiling Is Not Present on Hands

ABSTRACT

Suboptimal food worker health and hygiene has been a common contributing factor in foodborne disease outbreaks for many years. Despite clear U.S. Food and Drug Administration (FDA) Model Food Code recommendations for hand washing and glove use, food worker compliance with hand washing recommendations has remained poor for >20 years. Food workers' compliance with recommended hand washing guidelines is adversely impacted by a number of barriers, including complaints of time pressure, inadequate number and/or location of hand washing sinks and hand washing supplies, lack of food knowledge and training regarding hand washing, the belief that wearing gloves obviates the need for hand washing, insufficient management commitment, and adverse skin effects caused by frequent hand washing. Although many of the issues related to poor hand washing practices in food service facilities are the same as those in health care settings, a new approach to health care hand hygiene was deemed necessary >15 years ago due to persistently low compliance rates among health care personnel. Evidence-based hand hygiene guidelines for health care settings were published by both the Centers for Disease Control and Prevention in 2002 and by the World Health Organization in 2009. Despite similar low hand washing compliance rates among retail food establishment workers, no changes in the Food Code guidelines for hand washing have been made since 2001. In direct contrast to health care settings, where frequent use of alcohol-based hand sanitizers (ABHSs) in lieu of hand washing has improved hand hygiene compliance rates and reduced infections, the Food Code continues to permit the use of ABHSs only after hands have been washed with soap and water. This article provides clear evidence to support modifying the FDA Model Food Code to allow the use of ABHSs as an acceptable alternative to hand washing in situations where heavy soiling is not present. Emphasis on the importance of hand washing when hands are heavily soiled and appropriate use of gloves is still indicated.

HIGHLIGHTS

Skin Reactions to Personal Protective Equipment among First-Line COVID-19 Healthcare Workers: A Survey in Northern Morocco

Objectives

Health care workers (HCWs) adopted several protective measures, including hand hygiene and wearing personal protective equipment (PPE) during the COVID-19 outbreak. However, the frequent use of these preventive measures can lead to skin reactions. Our study aimed to determine the frequency of these reactions in Northern Morocco. In addition, we also looked at the risk factors and the consequences of these injuries on work efficiency and performance.

Materials and Methods

An anonymous online survey was used to collect data, which was sent to 500 health workers in the study region. Descriptive and inferential statistics were used to analyze the data on IBM SPSS software.

Results

In total, 273/500 responded to the questionnaire (55%). For the participants’ profession, 41% were doctors, 32% were nursing staff, and 26% held other jobs. The general prevalence rate of adverse reactions for all health workers was (80%), including skin problems: after wearing goggles (58%), after wearing surgical masks and respirators (57%), after handwashing and wearing gloves (45%), after wearing a face shield (23%), and after wearing protective clothing (11%). Bleach immersion was highly significantly associated with hand reaction (OR: 2.9, 95% CI: 1.77–4.90; P < 0.001). Moreover, we found a statistically significant association between hand cream use more than twice daily and fewer reactions (OR: 1.9, 95% CI: 0.98–3.77; P = 0.038). The skin reactions related to goggles use were also significantly associated with use duration (OR: 1.7, 95% CI: 0.988–3.12; P = 0.05). Similarly, wearing masks and N95 respirators and their related adverse reactions were significantly associated with use duration (OR: 0.5, 95% CI: 0.20–0.7; P = 0.02). In addition, adverse reactions of regular use of protective clothing were related to the frequency of its use per shift (OR: 3.5, 95% CI: 1.47–8.54; P = 0.05).

Conclusions

Our survey-based study showed that the prevalence of these skin reactions in our context should not be neglected. The length of daily wearing time and the frequency of PPE uses were the most implicated factors. More attention must be paid to these reactions for better care of HCWs during these critical times.

Human Skin Microbiome: Impact of Intrinsic and Extrinsic Factors on Skin Microbiota

The skin is the largest organ of the human body and it protects the body from the external environment. It has become the topic of interest of researchers from various scientific fields. Microorganisms ensure the proper functioning of the skin. Of great importance, are the mutual relations between such microorganisms and their responses to environmental impacts, as dysbiosis may contribute to serious skin diseases. Molecular methods, used for microorganism identification, allow us to gain a better understanding of the skin microbiome. The presented article contains the latest reports on the skin microbiota in health and disease. The review discusses the relationship between a properly functioning microbiome and the body's immune system, as well as the impact of internal and external factors on the human skin microbiome.

Hand hygiene: virucidal efficacy of a liquid hand wash product against Ebola virus

Background

Hand washing is an important targeted hygiene intervention for limiting the spread of infectious agents, including the Ebola virus, which continues to re-emerge. We have assessed the virucidal efficacy of a commercially available liquid hand wash product (LHW) for inactivating Ebola virus.

Methods

The ASTM E1052-11 Standard was used to evaluate the efficacy of an LHW containing the microbicidal active salicylic acid for inactivating Ebola virus - Makona variant suspended in an organic load. Three concentrations (12.5%, 25%, 50%) of three lots of LHW prepared in 440 ppm hard water were evaluated at room temperature for 20, 30, and 60 s contact time.

Results

A 25% solution of the LHW caused 4.5 log₁₀ and 4.8 log₁₀ reduction in Ebola virus titer within 20 and 30 s, respectively. The efficacy of a 12.5% LHW solution was lower (1.9 and 2.0 log₁₀ reduction in titer within 20 and 30 s, respectively). The efficacy of the 50% LHW solution could not be measured, due to inability to sufficiently neutralize the LHW at the end of exposure.

Conclusion

These results suggest the potential utility of an appropriately formulated liquid hand wash agent during Ebola virus disease outbreaks for use within healthcare, community, and home settings. Such an LHW should also be effective against other enveloped viruses, such as the pandemic coronavirus SARS-CoV-2.

A review of wipes used to disinfect hard surfaces in health care facilities

BACKGROUND

Despite a plethora of wipes available for use in health care facilities, there is a paucity of articles describing wipe composition, potential interactions between wipes and disinfectants, the manner in which wipes are used, and their relative efficacy. The purpose of this article is to provide an in-depth review of wipes used for disinfection of hard surfaces in health care settings.

METHODS

Comprehensive searches of the Pubmed database and Internet were conducted, and articles published from 1953 through September 2019 and pertinent on-line documents were reviewed. Bibliographies of relevant articles were reviewed.

RESULTS

Wipes vary considerably in their composition, and the disinfectants with which they are used. With reusable dry wipes, the ratio of wipe material to disinfectant and the amount of disinfectant absorbed by the wipe and delivered to surfaces is difficult to standardize, which may affect their efficacy. The manner in which wipes are used by health care personnel is highly variable, due in part to insufficient instructions for use and inadequate education of relevant personnel.

CONCLUSIONS

Additional research is needed regarding the best practices for using different types of wipes, improved methods for educating staff, and establishing the relative efficacy of wipes in reducing environmental contamination and health care-associated infections.

Hand sanitizers: A review of ingredients, mechanisms of action, modes of delivery, and efficacy against coronaviruses

Background

The emergence of the novel virus, SARS-CoV-2, has posed unprecedented challenges to public health around the world. Currently, strategies to deal with COVID-19 are purely supportive and preventative, aimed at reducing transmission. An effective and simple method for reducing transmission of infections in public or healthcare settings is hand hygiene. Unfortunately, little is known regarding the efficacy of hand sanitizers against SARS-CoV-2.

Methods

In this review, an extensive literature search was performed to succinctly summarize the primary active ingredients and mechanisms of action of hand sanitizers, compare the effectiveness and compliance of gel and foam sanitizers, and predict whether alcohol and non-alcohol hand sanitizers would be effective against SARS-CoV-2.

Results

Most alcohol-based hand sanitizers are effective at inactivating enveloped viruses, including coronaviruses. With what is currently known in the literature, one may not confidently suggest one mode of hand sanitizing delivery over the other. When hand washing with soap and water is unavailable, a sufficient volume of sanitizer is necessary to ensure complete hand coverage, and compliance is critical for appropriate hand hygiene.

Conclusions

By extrapolating effectiveness of hand sanitizers on viruses of similar structure to SARS-CoV-2, this virus should be effectively inactivated with current hand hygiene products, though future research should attempt to determine this directly.

Techno-Economic Evaluation of Hand Sanitiser Production Using Oil Palm Empty Fruit Bunch-Based Bioethanol by Simultaneous Saccharification and Fermentation (SSF) Process

Oil palm empty fruit bunch (OPEFB) is a potential raw material abundantly available for bioethanol production. However, the second-generation bioethanol is still not yet economically feasible. The COVID-19 pandemic increases the demand for ethanol as the primary ingredient of hand sanitisers. This study evaluates the techno-economic feasibility of hand sanitiser production using OPEFB-based bioethanol. OPEFB was alkaline-pretreated, and simultaneous saccharification and fermentation (SSF) was then performed by adding Saccharomyces cerevisiae and cellulose enzyme. The cellulose content of the OPEFB increased from 39.30% to 63.97% after pretreatment. The kinetic parameters of the OPEFB SSF at 35 °C, which included a µ max, ks, and kd of 0.018 h−1, 0.025 g/dm3, and 0.213 h−1, respectively, were used as input in SuperPro Designer® v9.0. The total capital investment (TCI) and annual operating costs (AOC) of the plant were $645,000 and $305,000, respectively, at the capacity of 2000 kg OPEFB per batch. The batch time of the modelled plant was 219 h, with a total annual production of 32,506.16 kg hand sanitiser. The minimum hand sanitiser selling price was found to be $10/L, achieving a positive net present value (NPV) of $108,000, showing that the plant is economically feasible.

Comparison of estimated norovirus infection risk reductions for a single fomite contact scenario with residual and nonresidual hand sanitizers

BACKGROUND

The purpose of this study was to relate experimentally measured log₁₀ human norovirus reductions for a nonresidual (60% ethanol) and a residual (quaternary ammonium-based) hand sanitizer to infection risk reductions.

METHODS

Human norovirus log₁₀ reductions on hands for both sanitizers were experimentally measured using the ASTM International Standard E1838-10 method, with modification. Scenarios included product application to: (1) inoculated fingerpads with 30- and 60-second contact times, and (2) hands followed by inoculation with human norovirus immediately and 4 hours later. Hand sanitizer efficacies were used in a mathematical model estimating norovirus infection risk from a single hand-to-fomite contact under low and high environmental contamination conditions.

RESULTS

The largest log₁₀ reductions for the residual and nonresidual hand sanitizers were for a 60-second contact time, reducing infection risk by approximately 99% and 85%, respectively. Four hours after application, the residual hand sanitizer reduced infection risks by 78.5% under high contamination conditions, whereas the nonresidual hand sanitizer offered no reduction.

DISCUSSION

Log₁₀ virus and infection risk reductions were consistently greater for the residual hand sanitizer under all scenarios. Further data describing residual hand sanitizer efficacy with additional contamination or tactile events are needed.

CONCLUSIONS

Residual antinoroviral hand sanitizers may reduce infection risks for up to 4 hours.

In-flight transmission of foodborne disease: How can airlines improve?

Food contamination during air travel presents unique risks to those affected. Foodborne pathogens can cause serious illness among all on board, and potentially jeopardize flight safety. These risks are likely to increase with current trends of "densification" and a predicted massive expansion of air travel. While aircraft are being equipped with ever newer designs with a focus on efficiency and comfort, regulations remained largely unmodified in terms of basic hygiene requirements. Strict guidelines for food hygiene exist for on-ground food settings and catering kitchens. There is uncertainty about hygiene standards on board commercial aircraft, and little regulatory oversight of what happens to food in-flight. In two hypothetical scenarios we indicate the potential risks associated with poor food handling practice onboard aircraft, with the ultimate aim of bringing aviation food safety in line with on-ground regulations. Changes in cabin design alongside adequate training in safe food handling have the potential to increase public health protection. We urge a review of existing in-flight hygiene protocols to better direct the development of regulation, prevention, and intervention measures for aviation food safety.

Is open defaecation in outdoor recreation and camping areas a public health issue in Australia? A literature review

Issue addressed

In Australia, natural areas used for outdoor recreation activities or camping often have limited or no sanitation infrastructure. Recreationist and campers may use open defaecation practices where toilets are not provided. Contaminated soils and watercourses are associated with gastrointestinal illnesses. This review aims to determine if open defaecation is a public health issue in outdoor recreation and camping areas in Australia.

Method

A literature review was conducted using the following search engines: CINAHL, Informit Database, Scopus, ProQuest Science & Technology, Medline (Ovid) and EBSCOhost. Inclusion criteria for this review were both experimental and observational research designs for studies describing the public health issues associated with open defaecation practice.

Results

Out of 12 147 papers identified, only three studies met the inclusion criteria, showing a lack of research into this area. Included were two studies that addressed human waste management practices in outdoor environments and the breakdown of human waste in alpine regions of Tasmania. The third study measured water contamination at a freshwater beach on K'gari‐Fraser Island, Queensland. Visitors to natural areas are potentially at high risk of illness due to exposure to faecal contamination from other visitors using unsafe open defaecation practices in high‐use camping areas.

Conclusion

The limited number of studies addressing open defaecation in the outdoor recreation and camp areas in Australia indicates this review is a starting point to identify critical areas that may be of concern when managing visitors in an outdoor recreation setting. This review recommends investigating barriers and enablers motivating human disposal waste in these settings to help formulate health promotion content; environmental management policies related to sanitation and hygiene should be also underpinned by public health policy; and providing appropriate sanitation options depending on the ecological and visitor numbers to natural areas.

So what‐relevance of findings

Outdoor recreation activities offer physical and mental health benefits for communities. The popularity of outdoor recreation activities is on the increase in Australia. With the rise in visitation to natural areas, management of human waste needs to be addressed to reduce the public health risk of illness.

Microbial Quality and Safety of Sushi Prepared with Gloved or Bare Hands: Food Handlers' Impact on Retail Food Hygiene and Safety

Food handlers play an important role in retail food hygiene and safety. This study was conducted to better understand the impact of food handlers on the microbiological quality and safety of sushi and ingredients handled by gloved and bare hands. At retail premises, food handlers were asked to prepare a batch of sushi with raw fish followed by a batch of sushi with cooked ingredients. Food (sushi and ready-to-eat ingredients), hand, and glove samples were collected for analysis of overall microorganisms (standard plate counts) and targeted foodborne bacteria: Staphylococcus aureus, Bacillus cereus, Escherichia coli, Salmonella, and Listeria monocytogenes. Results suggested that cross-contamination was more prevalent at premises where bare hands were used to prepare sushi. When bare hands were used, significantly higher standard plate counts were obtained from samples of cooked rice (2.3 to 4.9 log CFU/g) and sushi (2.8 to 6.9 log CFU/g) and the prevalence of S. aureus in samples was higher on food (21.7%, 28 of 129 samples) and hands (30%, 18 of 60 samples) ( P < 0.05). Glove changing in combination with hand washing minimized cross-contamination during sushi preparation as indicated by the lower prevalence of S. aureus (0%, 0 of 28 samples) and total targeted foodborne bacteria (3.6%, 1 of 28 samples) on the gloves of food handlers who changed gloves and washed their hands compared with those handlers who did not don new gloves. Repeated use of dishcloths could be a cause of cross-contamination, and the prevalence of total targeted foodborne bacteria was significantly higher on hands dried with dishcloths (64.7%, 11 of 17 samples) than on hands dried with paper towels (12.5%, 1 of 8 samples) ( P < 0.05). The prevalences of B. cereus, L. monocytogenes, and Salmonella in the 356 food samples were 5.1% (18 samples), 0.8% (3 samples), and 0%, respectively. Improvements to hand washing, hand drying, and glove changing practices are needed to lower the occurrence of cross-contamination during sushi preparation.

Safely Managed Hygiene: A Risk-Based Assessment of Handwashing Water Quality

Sustainable Development Goal (SDG) Indicator 6.2.1 requires household handwashing facilities to have soap and water, but there are no guidelines for handwashing water quality. In contrast, drinking water quality guidelines are defined: water must be "free from contamination" to be defined as "safely managed" (SDG Indicator 6.1.1). We modeled the hypothesized mechanism of infection due to contaminated handwashing water to inform risk-based guidelines for microbial quality of handwashing water. We defined two scenarios that should not occur: (1) if handwashing caused fecal contamination, indicated using Escherichia coli, on a person's hands to increase rather than decrease and (2) if hand-to-mouth contacts following handwashing caused an infection risk greater than an acceptable threshold. We found water containing <1000 E. coli colony-forming units (CFU) per 100 mL removes E. coli from hands with>99.9% probability. However, for the annual probability of infection to be <1:1000, handwashing water must contain <2 × 10^-6 focus-forming units of rotavirus, <1 × 10^-4 CFU of Vibrio cholerae, and <9 × 10^-6 Cryptosporidium oocysts per 100 mL. Our model suggests that handwashing with nonpotable water will generally reduce fecal contamination on hands but may be unable to lower the annual probability of infection risks from hand-to-mouth contacts below 1:1000.

Biology of Hand-to-Hand Bacterial Transmission

Numerous studies have demonstrated that adequate hand hygiene among hospital staff is the best measure to prevent hand-to-hand bacterial transmission. The skin microbiome is conditioned by the individual physiological characteristics and anatomical microenvironments. Furthermore, it is important to separate the autochthonous resident microbiota from the transitory microbiota that we can acquire after interactions with contaminated surfaces. Two players participate in the hand-to-hand bacterial transmission process: the bacteria and the person. The particularities of the bacteria have been extensively studied, identifying some genera or species with higher transmission efficiency, particularly those linked to nosocomial infections and outbreaks. However, the human factor remains unstudied, and intrapersonal particularities in bacterial transmission have not been yet explored. Herein we summarize the current knowledge on hand-to-hand bacterial transmission, as well as unpublished results regarding interindividual and interindividual transmission efficiency differences. We designed a simple in vivo test based on four sequential steps of finger-to-finger contact in the same person artificially inoculated with a precise bacterial inoculum. Individuals can be grouped into one of three observed transmission categories: high, medium, and poor finger-to-finger transmitters. Categorization is relevant to predicting the ultimate success of a human transmission chain, particularly for the poor transmitters, who have the ability to cut the transmission chain. Our model allowed us to analyze transmission rate differences among five bacterial species and clones that cause nosocomial infections, from which we detected that Gram-positive microorganisms were more successfully transmitted than Gram-negative.

The contribution of hand drying in prevention of transmission of microorganisms: Comparison of the efficacy of three hand drying methods in the removal and distribution of microorganisms

Background

Hand hygiene is a key tool in infection control. While methods of hand washing have been widely researched, there have been fewer studies investigating the effectiveness of available ways to dry hands in public areas.

Aims

This study compared the efficacy of using paper towels (PT), warm air dryers (WAD) and jet air dryers (JAD) after hand washing in terms of microbiological effectiveness and potential for dispersal of pathogens.

Methods

Microbial flora on palms and fingertips of 30 subjects were sampled on nutrient agar plates before washing hands and after drying with PTs, WADs and JADs. Total colony forming units (cfus) were recorded. Walls in the vicinity of a PT dispenser, WAD and JAD in female and male washrooms were sampled for the presence of viable microorganisms.

Results

Mean cfu significantly reduced after drying with PTs (palms t= 2.67, p <0.05; fingertips t=4.44, p<0.01) significantly increased after using WADs (palms t=3.11, p<0.01; fingertips t=2.06, p<0.05), but there was no difference with JAD (palms t= 1.85, p>0.05; fingertips t=0.97, p>0.05). Some dispersal of organisms was detected on the washroom walls, with the least distribution around PT dispensers and unusual opportunistic pathogens isolated from the JAD units.

Discussion

PTs are more effective at drying hands than WADs and JADs, they are more likely to be used appropriately and lead to minimal dispersal of microorganisms from wet hands.

Quantitative Risk Assessment of Norovirus Transmission in Food Establishments: Evaluating the Impact of Intervention Strategies and Food Employee Behavior on the Risk Associated with Norovirus in Foods

We developed a quantitative risk assessment model using a discrete event framework to quantify and study the risk associated with norovirus transmission to consumers through food contaminated by infected food employees in a retail food setting. This study focused on the impact of ill food workers experiencing symptoms of diarrhea and vomiting and potential control measures for the transmission of norovirus to foods. The model examined the behavior of food employees regarding exclusion from work while ill and after symptom resolution and preventive measures limiting food contamination during preparation. The mean numbers of infected customers estimated for 21 scenarios were compared to the estimate for a baseline scenario representing current practices. Results show that prevention strategies examined could not prevent norovirus transmission to food when a symptomatic employee was present in the food establishment. Compliance with exclusion from work of symptomatic food employees is thus critical, with an estimated range of 75-226% of the baseline mean for full to no compliance, respectively. Results also suggest that efficient handwashing, handwashing frequency associated with gloving compliance, and elimination of contact between hands, faucets, and door handles in restrooms reduced the mean number of infected customers to 58%, 62%, and 75% of the baseline, respectively. This study provides quantitative data to evaluate the relative efficacy of policy and practices at retail to reduce norovirus illnesses and provides new insights into the interactions and interplay of prevention strategies and compliance in reducing transmission of foodborne norovirus.

Removal of Escherichia coli and Enterococcus faecalis after Hand Washing with Antimicrobial and Nonantimicrobial Soap and Persistence of These Bacteria in Rinsates

Food handlers are important sources of contamination in the agricultural environment. This study was conducted (i) to evaluate the activity of antimicrobial soaps against Escherichia coli and Enterococcus faecalis using a hand washing model with soiled hands and (ii) to determine the survival and persistence of these bacteria in rinsates. Sterilized agricultural soil from tomato and pepper farms was inoculated with E. coli or E. faecalis at 10³ or 10⁶ CFU/g. Decontaminated hands were placed in contact with contaminated soil for 2 min and were then washed with soaps with or without antimicrobial compounds (citric extracts, chloroxylenol, triclosan, or chlorhexidine gluconate). As the control, hands were washed with sterile distilled water. The levels of bacteria remaining on the hands and recovered from the rinsates were determined using a membrane filtration method and selective media. Antimicrobial soaps removed levels of E. coli similar to those removed by distilled water and nonantimicrobial soap on hands contaminated with E. coli at 10³ CFU/g. However, when hands were contaminated with E. coli at 10⁶ CFU/g, more E. coli was removed with the chlorhexidine gluconate soap. When hands were contaminated with E. faecalis at 10³ CFU/g, bacteria were removed more effectively with soaps containing chloroxylenol or chlorhexidine gluconate. When hands were contaminated with E. faecalis at 10⁶ CFU/g, all of the antimicrobial soaps were more effective for removing the bacteria than were distilled water and nonantimicrobial soap. E. coli grew in all of the hand washing rinsates except that containing triclosan, whereas E. faecalis from the 10⁶ CFU/g treatments grew in rinsates containing chlorhexidine gluconate and in the distilled water rinsates. Washing with antimicrobial soap was more effective for reducing bacteria on soiled hands than was washing with water or nonantimicrobial soap. However, persistence or growth of bacteria in these rinsates poses health risks.