Outbreaks where food workers have been implicated in the spread of foodborne disease. Part 6. Transmission and survival of pathogens in the food processing and preparation environment

Food Safety Controls during Bulk Food Preparation-An Observational Analysis

Seeing the palpable impact of food poisoning associated with catering operations, we surveyed caterers with and without past hygiene violations to examine staffing, food safety practices and correlations with microbial counts in food and the processing environment. Past infringements did not negatively impact the current execution of food safety measures nor the microbial quality of food. In preference to added stringencies for errant operators, we discuss alternative efforts to augment food safety, as well as the policy implications thereof.

Surface Hygiene Evaluation Method in Food Trucks as an Important Factor in the Assessment of Microbiological Risks in Mobile Gastronomy

Street food outlets are characterised by poor microbiological quality of the food and poor hygiene practices that pose a risk to consumer health. The aim of the study was to evaluate the hygiene of surfaces in food trucks (FT) using the reference method together with alternatives such as Petrifilm^TM and the bioluminescence method. TVC, S. aureus, Enterobacteriaceae, E. coli, L. monocytogenes, and Salmonella spp. were assessed. The material for the study consisted of swabs and prints taken from five surfaces (refrigeration, knife, cutting board, serving board, and working board) in 20 food trucks in Poland. In 13 food trucks, the visual assessment of hygiene was very good or good, but in 6 FTs, TVC was found to exceed log 3 CFU/100 cm² on various surfaces. The assessment of surface hygiene using various methods in the food trucks did not demonstrate the substitutability of culture methods. Petrifilm^TM tests were shown to be a convenient and reliable tool for the monitoring of mobile catering hygiene. No correlation was found between the subjective visual method and the measurement of adenosine 5-triphosphate. In order to reduce the risk of food infections caused by bacteria in food trucks, it is important to introduce detailed requirements for the hygiene practices used in food trucks, including techniques for monitoring the cleanliness of surfaces coming into contact with food, in particular cutting boards and work surfaces. Efforts should be focused on introducing mandatory, certified training for food truck personnel in the field of microbiological hazards, appropriate methods of hygienisation, and hygiene monitoring.

Assessment of Microbial Source Tracking Marker and Fecal Indicator Bacteria on Food-Contact Surfaces in School Cafeterias

Food poisoning outbreaks in schools can affect many students, causing physical and psychological damage and time and economic loss. Fecal indicator bacteria (FIB) have been used to monitor the contamination; however, the detection is time-consuming and confirms the contamination from all warm-blooded animals. Microbial source tracking (MST) is a molecular-based detection method that is host specific. This study aimed to evaluate MSTs and FIBs for tracing contamination in the school cafeteria. The average total aerobic count was 0.89 to 3.63 log CFU/100 cm2, and the faucets in the cooking area showed a significantly high aerobic count. The stove valve, faucet, and hand-washer were the most contaminated area, with a concentration of 1.90 to 6.80 log CFU/100 cm2 from the frequent hand contact. Escherichia coli was not detected on any surfaces, and coliform was detected on five surfaces: the sink and faucet in the food preparation area, the faucet in the cooking area, the hand-washer, and the toilet seat in the restroom with 0.33 to 3.64 log CFU/100 cm2. Human-specific crAssphage appeared on a faucet in the food preparation area, while HF183 was not detected. The result indicates that the continuous monitoring of frequent hand-contact areas is recommended to maintain the hygiene condition in the school cafeteria.

Colorimetric detection of norovirus by helicase-dependent amplification method based on specific primers integrated with HRPzyme

Noroviruses (NoVs) are the most common causes of epidemic gastroenteritis, responsible for at least 50% of all gastroenteritis outbreaks worldwide and significant causes of foodborne illness. In the USA, approximately 21 million illnesses attributable to NoVs have annually occurred. Therefore, there is a great demand to develop a rapid, low-cost, and accurate detection method for NoVs. This study first reported colorimetric helicase-dependent amplification (HDA) methods based on specific primers integrated with HRPzyme for the rapid and sensitive detection of NoV GI and GII. The colorimetric HDA methods exhibited a detection limit of 10 copies mL^-1 of each NoV GI and GII and were confirmed to be specific to each NoV GI and GII. The period required to complete the HDA method was 2 h, including a step of RNA extraction and cDNA synthesis without expensive instruments such as a thermal cycler and detector. The cutoff value of the method for the oyster artificially inoculated with a known amount of NoV was all 10² copies g^-1 for NoV GI and GII. Therefore, the HDA method developed in this study can be useful tool for the on-site detection of NoVs in food samples.

Food, Beverage, and Feedstock Processing Facility Wastewater: a Unique and Underappreciated Source of Contaminants to U.S. Streams

Process wastewaters from food, beverage, and feedstock facilities, although regulated, are an under-investigated environmental contaminant source. Food process wastewaters (FPWWs) from 23 facilities in 17 U.S. states were sampled and documented for a plethora of chemical and microbial contaminants. Of the 576 analyzed organics, 184 (32%) were detected at least once, with concentrations as large as 143 μg L^-1 (6:2 fluorotelomer sulfonic acid), and as many as 47 were detected in a single FPWW sample. Cumulative per/polyfluoroalkyl substance concentrations up to 185 μg L^-1 and large pesticide transformation product concentrations (e.g., methomyl oxime, 40 μg L^-1; clothianidin TMG, 2.02 μg L^-1) were observed. Despite 48% of FPWW undergoing disinfection treatment prior to discharge, bacteria resistant to third-generation antibiotics were found in each facility type, and multiple bacterial groups were detected in all samples, including total coliforms. The exposure-activity ratios and toxicity quotients exceeded 1.0 in 13 and 22% of samples, respectively, indicating potential biological effects and toxicity to vertebrates and invertebrates associated with the discharge of FPWW. Organic contaminant profiles of FPWW differed from previously reported contaminant profiles of municipal effluents and urban storm water, indicating that FPWW is another important source of chemical and microbial contaminant mixtures discharged into receiving surface waters.

Evaluation of glove type on survival and transfer of Escherichia coli in model systems and during hand harvesting of lettuce

BACKGROUND

Both reusable and single-use gloves can be employed during hand harvesting of lettuce and leafy greens. The impact of glove type on survival and transfer of Escherichia coli was evaluated using agar or lettuce in a laboratory setting and during simulated lettuce harvesting in the field.

RESULTS

Textured and smooth reusable latex and smooth disposable latex gloves inoculated with E. coli were sequentially touched to 10 or 20 agar plates or 20 lettuce leaves (n = 6; laboratory) or used to sequentially harvest 20 heads of lettuce (n = 6; field). E. coli was recovered by enrichment from significantly fewer leaves (46%; 55 of 120) or heads (26%; 31 of 120) of lettuce when inoculated reusable textured gloves were used compared with disposable gloves (leaves: 98%; 118 of 120, or heads: 74%; 89 of 120). In contrast, when a single head of lettuce was the point source for glove contamination, there was no significant difference in the number of E. coli-positive lettuce heads harvested with reusable textured (71%; 85 of 120) or disposable gloves (75%; 90 of 120). In either field-contamination scenario, at the 20th head of lettuce harvested with a single glove (final sample point), E. coli was recovered from one to five of six lettuce heads across experimental trials.

CONCLUSION

Contamination of a glove from a single point source can lead to subsequent contamination of multiple heads of lettuce during hand harvesting, showing the importance of policies to manage hand hygiene and glove use for harvest crews.

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.

Cross-Contamination on Atypical Surfaces and Venues in Food Service Environments

ABSTRACT

Cross-contamination of raw food to other surfaces, hands, and foods is a serious issue in food service. With individuals eating more meals away from home, contracting a foodborne illness from a food service establishment is an increasing concern. However, most studies have concentrated on hands or food contact surfaces and neglected atypical and unusual surfaces (surfaces that are not typically identified as a source of cross-contamination) and venues. This review was conducted to identify atypically cross-contaminated surfaces and atypical venues where cross-contamination could occur that have not been examined thoroughly in the literature. Most surfaces that could be at risk for cross-contamination are frequently touched, are rarely cleaned and sanitized, and can support the persistence and/or growth of foodborne pathogens. These surfaces include menus, spice and condiment containers, aprons and coveralls, mobile devices and tablets, and money. Venues that are explored, such as temporary events, mobile vendors, and markets, are usually limited in space or infrastructure, have low compliance with proper hand washing, and provide the opportunity for raw and ready-to-eat foods to come into contact with one another. These factors create an environment in which cross-contamination can occur and potentially impact food safety. A more comprehensive cleaning and sanitizing regime encompassing these surfaces and venues could help mitigate cross-contamination. This review highlights key surfaces and venues that have the potential to be cross-contaminated and have been underestimated or not fully investigated. These knowledge gaps indicate where further work is needed to fully understand the role of these surfaces and venues in cross-contamination and how it can be prevented.

HIGHLIGHTS

COVID-19 pandemic and emerging plastic-based personal protective equipment waste pollution and management in Africa

The threat of plastic waste pollution in African countries is increasing exponentially since the World Health Organisation declared the coronavirus infection as a pandemic. Fundamental to this growing threat are multiple factors, including the increased public consumption for single-use plastics, limited or non-existence of adequate plastic waste management infrastructures, and urbanisation. Plastics-based personal protective equipment including millions of surgical masks, medical gowns, face shields, safety glasses, protective aprons, sanitiser containers, plastics shoes, and gloves have been widely used for the reduction of exposure risk to Severe Acute Respiratory Syndrome (SARS) Coronavirus 2 (SARS-CoV-2). This paper estimates and elucidates the growing plethora of plastic wastes in African countries in the context of the current SARS-CoV-2 pandemic. A Fourier transform infrared (FTIR) spectral fingerprint indicates that face masks were characterised by natural and artificial fibres including polyester fibres, polypropylene, natural latex resin. Our estimate suggests that over 12 billion medical and fabric face masks are discarded monthly, giving the likelihood that an equivalent of about 105,000 tonnes of face masks per month could be disposed into the environment by Africans. In general, 15 out of 57 African countries are significant plastic waste contributors with Nigeria (15%), Ethiopia (8.6%), Egypt (7.6%), DR Congo (6.7%), Tanzania (4.5%), and South Africa (4.4%) topping the list. Therefore, this expert insight is an attempt to draw the attention of governments, healthcare agencies, and the public to the potential risks of SARS-CoV-2-generated plastics (COVID plastic wastes), and the environmental impacts that could exacerbate the existing plastic pollution epidemic after the COVID-19 pandemic.

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

Critical Food Safety Issues Facing the Food Industry: A Delphi Analysis

ABSTRACT

The topic of food safety continues to receive increased attention and has ramifications on various human, environmental, policy, and economic levels worldwide. By garnering feedback from 30 food industry experts, this study was undertaken to identify the most critical issues facing the food industry in relation to food safety. According to expert opinion and after three rounds of Delphi inquiry, food contamination detection, outbreaks, and prevention along with governmental oversight, education for and communication with consumers and employees, and globalization were identified as the main areas at the forefront of food safety. Delphi and constant comparative research methods are explained, and suggestions on how to make meaning from the results to progress in this area are discussed.

HIGHLIGHTS

In the landscape of SARS-CoV-2 and fresh fruits and vegetables: The fake and hidden transmission risks

From the first notification reporting to the WHO a cluster of coronavirus in Wuhan City (China), over 114 million cases of SARS‐CoV‐2 have been confirmed, with more than 2,530,000 deaths, and over 400,000 new cases and 10,000 deaths daily. Numerous viruses are susceptible to contaminate crops during growth, harvesting, handling, marketing and minimally processing, and these steps share one common factor which is human. Different studies showed that viruses might persist on different crops for periods of 2 to 14 days under different conditions such as refrigeration, household and freezing. Little is known on SARS‐CoV‐2, but preliminary studies showed that this virus might survive 24 hr on cardboard and 72 hr on plastic, materials used in fruits and vegetables packaging. Based on preliminary data, there is no evidence of food or food packaging being associated with transmission of SARS‐CoV‐2. Certainly, to date there is no scientific evidence that SARS‐CoV‐2 might be transmitted by a contact with, or the ingestion of contaminated fresh or minimally processed fruits and vegetables. However, this risk even though being considered improbable, it cannot be “completely and definitely” discarded or ignored, particularly where the virus is spreading in the word. Some agencies indicated that in case some commodities and handlers are contaminated among the multiple people involved from the farm to the table, a cross‐contamination may occur, and the risk of the contamination of food, food contact materials, and packaging from infected but asymptomatic workers should not be discarded even though considered “Very Low = meaning very rare but cannot be excluded.”

COVID pollution: impact of COVID-19 pandemic on global plastic waste footprint

Plastic products have played significant roles in protecting people during the COVID-19 pandemic. The widespread use of personal protective gear created a massive disruption in the supply chain and waste disposal system. Millions of discarded single-use plastics (masks, gloves, aprons, and bottles of sanitizers) have been added to the terrestrial environment and could cause a surge in plastics washing up the ocean coastlines and littering the seabed. This paper attempts to assess the environmental footprints of the global plastic wastes generated during COVID-19 and analyze the potential impacts associated with plastic pollution. The amount of plastic wastes generated worldwide since the outbreak is estimated at 1.6 million tonnes/day. We estimate that approximately 3.4 billion single-use facemasks/face shields are discarded daily as a result of COVID-19 pandemic, globally. Our comprehensive data analysis does indicate that COVID-19 will reverse the momentum of years-long global battle to reduce plastic waste pollution. As governments are looking to turbo-charge the economy by supporting businesses weather the pandemic, there is an opportunity to rebuild new industries that can innovate new reusable or non-plastic PPEs. The unanticipated occurrence of a pandemic of this scale has resulted in unmanageable levels of biomedical plastic wastes. This expert insight attempts to raise awareness for the adoption of dynamic waste management strategies targeted at reducing environmental contamination by plastics generated during the COVID-19 pandemic.

Evaluating the Behavior of Staphylococcus aureus and Bacillus cereus in Dairy- and Non-Dairy-Based Aqueous Slurries during Manufacturing of Table Spreads

ABSTRACT

High-moisture slurries used in the production of table spreads may permit growth of Staphylococcus aureus and Bacillus cereus and subsequent production of heat-stable enterotoxins. Compliance with the Food Safety Modernization Act (FSMA), specifically 21 CFR Part 117, subpart B and section 117.80 (c)(2) and (c)(3), requires a hazard analysis to determine whether preventive controls are needed. This study estimates the risk of potential growth of S. aureus and B. cereus in eight different dairy- and non-dairy-based slurries during extended storage and use. Mathematical models were used to screen which slurries might support the growth of S. aureus and B. cereus. Samples were individually inoculated with multiple strains of S. aureus and B. cereus to achieve a target level of 102 to 103 CFU/g. Inoculated and uninoculated slurry samples were incubated at typical holding temperatures of 35°C (95°F), 46.1°C (115°F), and 54.4°C (130°F). Samples were removed and tested following inoculation (time zero), after 4 and 12 h, and after 1, 2, 3, 4, 5, 6, 7, and 10 days of incubation at the target temperatures. All experiments were repeated in triplicate. Samples were analyzed for S. aureus and B. cereus using Baird-Parker agar and mannitol yolk polymyxin agar, respectively. Neither S. aureus nor B. cereus exceeded (P < 0.05) proposed food safety limits (105 CFU/g) at the evaluated experimental conditions. The study highlights the role of multiple hurdles (e.g., pH, potassium sorbate and sodium benzoate, salt, and other ingredients) in assuring microbiological safety of in-process dairy- and non-dairy-based slurries used in the production of table spreads. This study also found that mathematical models representative of product composition, intrinsic parameters, and experimental conditions can help risk managers make informed decisions during product development. Finally, the study findings indicate no significant risk of growth of the target pathogens associated with the dairy- and non-dairy-based aqueous slurries used in the routine manufacturing of table spreads.

HIGHLIGHTS

Both Handwashing and an Alcohol-Based Hand Sanitizer Intervention Reduce Soil and Microbial Contamination on Farmworker Hands during Harvest, but Produce Type Matters

Hand hygiene interventions are critical for reducing farmworker hand contamination and preventing the spread of produce-associated illness. Hand hygiene effectiveness may be produce-commodity specific, which could influence implementation strategies. This study's goal was to determine if produce commodity influences the ability of handwashing with soap and water or two-step alcohol-based hand sanitizer (ABHS) interventions to reduce soil and bacteria on farmworker hands. Farmworkers (n = 326) harvested produce (cantaloupe, jalapeño, and tomato) for 30 to 90 minutes before engaging in handwashing, two-step ABHS (jalapeño and cantaloupe), or no hand hygiene. Hands were rinsed to measure amounts of soil (absorbance at 600 nm) and indicator bacteria (coliforms, Enterococcus sp., generic Escherichia coli, and Bacteroidales universal [AllBac] and human-specific [BFD] 16S rRNA gene markers). Without hand hygiene, bacterial concentrations (0.88 to 5.1 log₁₀ CFU/hand) on hands significantly differed by the produce commodity harvested. Moderate significant correlations (ρ = -0.41 to 0.56) between soil load and bacterial concentrations were observed. There were significant produce-commodity-specific differences in the ability of handwashing and two-step ABHS interventions to reduce soil (P < 0.0001), coliforms (P = 0.002), and Enterococcus sp. (P = 0.003), but not the Bacteroidales markers AllBac (P = 0.4) or BFD (P = 0.3). Contamination on hands of farmworkers who harvested cantaloupe was more difficult to remove. Overall, we found that a two-step ABHS intervention was similar to handwashing with soap and water at reducing bacteria on farmworker hands. In summary, produce commodity type should be considered when developing hand hygiene interventions on farms.IMPORTANCE This study demonstrated that the type of produce commodity handled influences the ability of handwashing with soap and water or a two-step alcohol-based hand sanitizer (ABHS) intervention to reduce soil and bacterial hand contamination. Handwashing with soap and water, as recommended by the FDA's Produce Safety Rule, when tested in three agricultural environments, does not always reduce bacterial loads. Consistent with past results, we found that the two-step ABHS method performed similarly to handwashing with soap and water but also does not always reduce bacterial loads in these contexts. Given the ease of use of the two-step ABHS method, which may increase compliance, the two-step ABHS method should be further evaluated and possibly considered for implementation in the agricultural environment. Taken together, these results provide important information on hand hygiene effectiveness in three agricultural contexts.

Survival of foodborne pathogens on stainless steel soiled with different food residues

Insufficient and ineffective cleaning practices can cause food residues to remain in kitchen and can facilitate bacterial attachment and persistence by protective films. The present study investigated the survival of five major foodborne pathogens on stainless steel coupons, in the presence of cooked rice, whole eggs, and soymilk. Foodborne pathogens showed different survival rates by desiccation and disinfection depending on food residues. Overall, the pathogens showed stronger survival than the control at 0.13-3.97 log CFU/coupon with 5% residues, and at 0.75-5.29 log CFU/coupon with 50% residues. Staphylococcus aureus was not affected by the food residue with showing the least difference in concentration, while Escherichia coli O157:H7 showed the most significant increase by food residue. The cells with cooked rice were observed using FE-SEM, and demonstrated bacterial binding or embedment. All results suggest that food safety can be practically ensured by food residue types and appropriate cleaning and disinfectants.

Imprinting Pentaphyrin on Conductive Electropolymerized Dipyrromethane Films: A New Strategy towards the Synthesis of Photokilling Materials

We report herein the synthesis and photoinduced bactericidal activity of two new polymeric materials, obtained by imprinting the photosensitizer 20-(4-carboxyphenyl)-2,13-dimethyl-3,12-diethyl-[22]pentaphyrin (PCox, 1) into suitable electropolymerized dipyrromethane films. 5-Phenyl-dipyrromethane (5-ph-DP) and 5-(4-pyridyl)dipyrromethane (5-py-DP) have been selected as the monomers for the synthesis of the materials in order to assess the correlation between the substituent in C5 and the capability in Pcox uptake. Both films have been tested in their photokilling ability toward Staphylococcus aureus by using a multi-LED blue lamp at a fluence rate of 40 W/m² . Poly-5-py-DP/PCox, with a PCox load of 10^-8  mol/cm² , achieved a 4-log reduction in microbial viability after 60 min of irradiation. The polymeric films proved to be stable over time and under oxidation conditions; in addition, no loss of photosensitizer was observed during the experiments, thus demonstrating that the bactericidal action was effectively brought by the ROS generated by PCox immobilized in the material. After use, the films were recharged with PCox, with almost complete recovery of their photodynamic efficiency.

Monitoring of Hygiene in Institutional Kitchens in Belgium

ABSTRACT

Microbiological contamination of food during preparation and storage is a risk factor in institutional kitchens. In this Belgian study, hygiene practices in 40 institutional kitchens from four public sectors (10 hospitals, 10 schools, 10 retirement homes, and 10 child care centers) were evaluated to determine whether differences in these practices exist between these sectors. Contamination levels were also analyzed at several critical contact points. A data collection instrument and microbiological analysis of hand contact surfaces, food contact surfaces, and kitchen utensils were used. Hand washing resulted in only a slight reduction in total aerobic bacteria counts (TACs), and all microorganisms evaluated except E. coli were still present at countable levels. Enterobacteriaceae were found on one-third of the cleaned cutting boards. Cleaned work surfaces had the highest average TAC of all cleaned surfaces. Only slight improvements in TACs and Enterobacteriaceae and B. cereus counts were observed between used and cleaned work surfaces. The results from the data collection instrument revealed that child care centers had the lowest hygiene scores, whereas the other three sectors were fairly similar, with hospitals scoring highest. The low hygiene score for the child care centers was verified by comparing the results for cleaned surfaces among the sectors. The average TAC on surfaces was highest for child care centers and lowest for hospitals. Child care centers also had the second highest total mean counts and the highest number of total surface samples positive for Enterobacteriaceae. The highest number of surface samples positive for Staphylococcus aureus was also found in child care centers. This study highlights some areas of concern for hygiene improvement in institutional kitchens, differences between public sectors, and similarities in conclusions about hygiene based on the scores from the survey instrument and the results of the microbiological analyses.

HIGHLIGHTS

Antimicrobial Efficiency and Surface Interactions of Quaternary Ammonium Compound Absorbed on Dielectric Barrier Discharge (DBD) Plasma Treated Fiber-Based Wiping Materials

The physicochemical interactions between alkyldimethylbenzylammonium chloride (ADBAC) as disinfectant and three commercial wiping materials made from 100% polyester (PET), 55%cellulose/45%PET (blend), and 100% cellulose were investigated after treatment with dielectric barrier discharge (DBD) plasma at atmospheric pressure. Wipe material type in terms of cellulose content, liquor ratio, and immersion time demonstrated a significant influence on the adsorption of ADBAC. The higher the content of cellulose in the material, the higher is the adsorption of ADBAC active ingredient. The antimicrobial tests confirm that the ADBAC adsorbed on pure cellulosic material is inactivated losing its bactericidal activity, while 100% PET and blend wipes showed good antimicrobial efficacy. XPS analysis demonstrates the strong interactions of ADBAC with the plasma-generated oxygen species in the polyester-containing wipes surface. Unexpectedly, plasma-treated blend wipe displays a reverse antimicrobial effect compared to untreated samples, performing better in Gram-negative bacteria. The best result was obtained in the plasma treated 100% polyester wipe showing an improvement of about 20% in Gram-positive bacteria and an excellent performance in Gram-negative ones. This method allows the unprecedented use of pure polyester as effective wiping material for surface disinfection eliminating the major drawback of pure polyester, its high hydrophobicity.

Dangerous passengers: multidrug-resistant bacteria on hands and mobile phones

INTRODUCTION

It is recognized that mobile phones may play a role in microorganism transmission and that hand hygiene, is considered the most important action for preventing infections and the spread of pathogens. The objective of this study was to determine presence and circulation bacteria on hands and mobile phones capable of causing infections in people and also determine if disinfection with gel-alcohol is useful to reduce the bacterial colonization.

METHODS

The bacterial evaluation included 596 hands of participants and 256 mobile phones. Isolated colonies were identified by biochemical test and confirmed by gene 16S rRNA sequencing. Antimicrobial susceptibility was performed using the automated instrument Vitek®2-Compact and disk-diffusionmethod.

RESULTS

In total, 92.9% of mobile phones and 98.3% of participants in study demonstrated evidence of bacterial contamination with different types of bacteria. Surprisingly, we observed that 18.6% plaques inoculated with disinfected fingers showed bacterial growth. In general, Gram negative isolates showed resistance to a higher number of antibiotics tested than Gram positive isolates.

CONCLUSIONS

Our results could help to raise awareness in our society about the importance of hand hygiene, as well as frequently used devices, reducing bacterial contamination and limiting the possibility of transmission of resistant multi-drug bacteria.

Quantifying the Influence of Relative Humidity, Temperature, and Diluent on the Survival and Growth of Enterobacter aerogenes

Survival of bacteria on surfaces plays an important role in the cross-contamination of food. Temperature, relative humidity (RH), surface type, and inoculum diluent can affect bacterial survival. This study was conducted to examine how temperature, RH, and diluent affect the survival of Enterobacter aerogenes on stainless steel, polyvinyl chloride, and ceramic tile. Although surface type had little effect on survival, temperature had a clear effect. E. aerogenes survival was highest at 7°C and 15 and 50% RH on all surfaces. Some diluents allowed growth under high RH conditions. Cell populations in distilled water inoculated onto each surface decreased initially compared with populations in 1% phosphate-buffered saline (PBS) and 0.1% peptone broth. At 15 and 50% RH, cell populations in 1% PBS declined more sharply after 120 h than did those 0.1% peptone, but populations in both diluents had similar declines up to 3 weeks. Cell populations in 0.1% peptone had the greatest growth and reached the highest population density (∼8 log CFU/mL). Cell populations in PBS and distilled water increased by ∼2 log CFU/mL. When cells in 0.1% peptone were inoculated onto stainless steel at 100% RH, populations increased to ∼7 log CFU per coupon, whereas cells in 1% PBS increased to ∼5 log CFU per coupon followed by a decline over 3 weeks. DMFit and GInaFiT software modeled inactivation on surfaces at all conditions other than 100% RH at 21°C. These findings have important implications for experiments in which microorganisms are inoculated onto foods or food contact surfaces because the growth observed may be affected more by the inoculum diluent at high or uncontrolled RH than by the type of inoculated surface.

Tracking bacteriome variation over time in Listeria monocytogenes-positive foci in food industry

The variation in microbial composition over time was assessed in biofilms formed in situ on selected non-food and food contact surfaces of meat and fish industries, previously identified as Listeria monocytogenes-positive foci. First, all samples were analysed for the detection and quantification of L. monocytogenes using ISO 11290-1 and ISO 11290-2 norms, respectively. Although the pathogen was initially detected in all samples, direct quantification was not possible. Psychrotrophic bacteria counts were among resident microbiota in meat industry samples (Mean_max = 6.14 log CFU/cm²) compared to those form fish industry (Mean_max = 5.85 log CFU/cm²). Visual analysis of the biofilms using epifluorescence microscopy revealed a trend to form microcolonies in which damaged/dead cells would act as anchoring structures. 16S rRNA gene metagenetic analysis demonstrated that, although Proteobacteria (71.37%) initially dominated the bacterial communities at one meat industry location, there was a dramatic shift in composition as the biofilms matured, where Actinobacteria (79.72%) became the major phylum present in later samples. This change was largely due to an increase of Nocardiaceae, Micrococcaceae and Microbacteriaceae. Nevertheless, for the other sampling location, the relative abundance of the dominating phylum (Firmicutes) remained consistent over the entire sampling period (Mean = 63.02%). In fish industry samples, Proteobacteria also initially dominated early on (90.69%) but subsequent sampling showed a higher diversity in which Bacteroidetes and Proteobacteria were the most abundant phyla accounting for the 48.04 and 37.98%, respectively by the last sampling period. Regardless of the location, the community profiles of the endpoint samples were similar to those reported previously. This demonstrated that in a given industrial setting there is a trend to establish a determinate biofilm structure due to the environmental factors and the constant incoming microbiota. This information could be used to improve the existing sanitisation protocols or for the design of novel strategies.

Outbreak Investigation of a Multipathogen Foodborne Disease in a Training Institute in Rabat, Morocco: Case-Control Study

BACKGROUND

On June 18, 2017, the public health service was alerted about 43 students in the training institute in Rabat who were admitted to the emergency room for acute gastroenteritis following the uptake of a meal a day before.

OBJECTIVE

This study aimed to investigate the foodborne disease outbreak by confirming the outbreak, identifying the source of contamination, and recommending control measures.

METHODS

We conducted a case-control study. Cases and controls were selected in a ratio of 1:1. We defined a case as any member of the training institute who attended the Ramadan buffet in the institute's restaurant and who had presented, in the weekend of June 16 to 20, 2017, symptoms of diarrhea or vomiting with at least one of the following signs: abdominal pain, fever, headache, nausea, and dizziness. A control was defined as anyone who attended the Ramadan buffet in the institute's restaurant but had not presented any symptoms from June 16 to 20, 2017. We conducted a bivariate and multivariable analysis. Stools of ill students were collected, and a food specimen was collected for bacterial testing.

RESULTS

A total of 50 cases and 50 controls were selected. Among the cases, males were predominant (43/50, 86%); the median age was 21 years. A total of 47 cases sought medical care. There were no hospitalizations and no deaths. The episode was short with an estimated average incubation period of 9 hours. The epidemic curve oriented toward a common source of contamination. Among food items, briwates were strongly associated with the illness with an odd ratio of 14.23 (95% CI 5.04-40.04; P<.001). Laboratory testing of briwates showed presence of Escherichia coli O157 and Staphylococcus aureus.

CONCLUSIONS

This foodborne disease outbreak was likely caused by briwates that was contaminated with S aureus and E coli. We recommended strengthening hygiene measures. Food handling techniques should be taught as part of continuous professional development for food handlers.

Foodborne Parasites in Europe: Present Status and Future Trends

Although foodborne parasites (FBPs) are becoming recognized as important foodborne pathogens, they remain neglected compared with bacterial and viral foodborne pathogens. As drivers for infection with FBPs are variable, it is often unclear for funding bodies where research should be prioritized. Through a COST Action (Euro-FBP; FA1408), we harnessed Europe-wide expertise to address these questions, using an Expert Knowledge Elicitation approach. Eating habits, lack of food-chain control, lack of awareness from relevant agencies, globalization, and water quality were identified as major drivers for FBP infection. Prioritized research needs to be largely focused on methodological gaps, but also on surveillance concerns, impact-assessment issues, and the role of microbiota. Despite the European focus, these responses should be relevant to those concerned with FBPs globally.

Method to Study the Survival Abilities of Foodborne Bacterial Pathogens Under Food Processing Conditions

The proper use of controllable atmospheric containers can facilitate investigations related to the survival abilities, and physiological states of key and emerging foodborne pathogens under recreated applicable food processing environmental conditions. Of particular note, the use of saturated salt solutions can efficiently control relative humidity in airtight containers. This chapter describes a practical experimental setup, with necessary prerequisites for exposing foodborne pathogens to simulated and relevant food processing environmental conditions. Subsequent analyses for studying cell physiology will also be suggested.

Evaluation of prevalence and risk factors associated with Cryptosporidium infection in rural population of district Buner, Pakistan

BACKGROUND

Cryptosporidium spp are important intestinal protozoan parasites that cause diarrhea in humans, domestic and wild animals. Its infection remains a main public health concern however, the epidemics in human being is still unclear, particularly in developing countries. There are several factors that may enhance the spreading of this parasite in human population especially in young children.

METHODOLOGY

A questionnaire was designed to obtain the demographic and clinical data from the participants. A total of 425 stool samples were collected from suspected children (aged 3-10 years) in different hospitals and villages. The initial screening was performed with modified Ziehl Neelsen (mZN) staining technique followed by polymerase chain reaction (PCR). Several potential risk factors were also assessed through the obtained information from suspected individuals.

RESULTS

Out of all 425 collected samples, 127 were observed positive by mZN with a prevalence of 29.88% (127/425). The 127 mZN positive samples together with 50 mZN negative samples were processed for molecular analysis through PCR assay. Among them, 71 out of 127 mZN positive samples and 4 out of 50 mZN negative samples were found positive by PCR. The molecular analysis showed that Cryptosporidium parvum was the main cause of infection in children. The results revealed that individuals exposed to diarrhea were more likely to be infected with Cryptosporidium infection while several environmental factors may also play a key role in spreading of this parasite.

CONCLUSIONS/SIGNIFICANCE OF THE STUDY

The current high prevalence of Cryptosporidium infection may be due to the lack of awareness and routine based testing in identification of this parasite in District Buner. Further studies are required to determine the importance of Cryptosporidium infection in this area as well as across the country and to find out the possible risk factors that may be associated with the occurrence of this protozoan. There is, however, an urgent need for laboratory-based observational studies to develop a more dynamic estimate of the cryptosporidial disease burden in the region.

Microgreens-A review of food safety considerations along the farm to fork continuum

The food safety implications of microgreens, an emerging salad crop, have been studied only minimally. The farm to fork continuum of microgreens and sprouts has some overlap in terms of production, physical characteristics, and consumption. This review describes the food safety risk of microgreens as compared to sprouts, potential control points for microgreen production, what is known to date about pathogen transfer in the microgreen production environment, and where microgreens differ from sprouts and their mature vegetable counterparts. The synthesis of published research to date may help to inform Good Agricultural Practices (GAPs) and Good Handling Practices (GHPs) for the emerging microgreen industry.

Percepção sobre a higiene dos manipuladores de alimentos e perfil microbiológico em restaurante universitário

Resumo Este trabalho teve por objetivo analisar a percepção dos manipuladores de alimentos em relação às práticas de higiene no local de trabalho e a correlacionar com os resultados das análises bacteriológicas e das observações sistematizadas, em um Restaurante Universitário no Rio de Janeiro. A percepção da higiene foi investigada por meio de questionários de autorresposta. As práticas operacionais foram analisadas por meio de pesquisa observacional sistemática. Na pesquisa bacteriológica, dividida em duas etapas, buscou-se identificar a presença de Coliformes a 45°C, de Clostridium Sulfito Redutor, Staphylococcus coagulase positiva e Bactérias Heterotróficas Aeróbias Mesófilas nas mãos, nos Equipamentos de Proteção Individual e nos utensílios. Nos resultados da percepção dos manipuladores sobre a higiene pessoal, a higiene ambiental e a manipulação dos alimentos, obtiveram-se valores médios de 86.11; 96.73 e 83.76, respectivamente. Na pesquisa bacteriológica para mãos e Equipamentos de Proteção Individual, obteve-se 61,36% de resultados positivos, para as bactérias pesquisadas; quanto aos utensílios, 25% dos resultados foram positivos para as bactérias pesquisadas. Conclui-se que o serviço possui falhas, com riscos à saúde do consumidor.

Removal of Listeria monocytogenes dual-species biofilms using combined enzyme-benzalkonium chloride treatments

The effects of pronase (PRN), cellulase (CEL) or DNaseI alone or combined with benzalkonium chloride (BAC) against Listeria monocytogenes-carrying biofilms were assayed. The best removal activity against L. monocytogenes-Escherichia coli biofilms was obtained using DNaseI followed by PRN and CEL. Subsequently, a modified logistic model was used to quantify the combined effects of PRN or DNaseI with BAC. A better BAC performance after PRN compared to DNaseI eradicating L. monocytogenes was observed. In E. coli the effects were the opposite. Finally, effects of DNaseI and DNaseI-BAC treatments were compared against two different L. monocytogenes-carrying biofilms. DNaseI-BAC was more effective against L. monocytogenes when co-cultured with E. coli. Nonetheless, comparing the removal effects after BAC addition, these were higher in mixed-biofilms with Pseudomonas fluorescens. However, a high number of released viable cells was observed after combined treatments. These results open new perspectives of enzymes as an anti-biofilm strategy for environmental pathogen control.

Routes of Transmission in the Food Chain

More than 250 different foodborne diseases have been described to date, annually affecting about one-third of the world's population. The incidence of foodborne diseases has been underreported and underestimated, and the asymptomatic presentation of some of the illnesses, worldwide heterogeneities in reporting, and the alternative transmission routes of certain pathogens are among the factors that contribute to this. Globalization, centralization of the food supply, transportation of food products progressively farther from their places of origin, and the multitude of steps where contamination may occur have made it increasingly challenging to investigate foodborne and waterborne outbreaks. Certain foodborne pathogens may be transmitted directly from animals to humans, while others are transmitted through vectors, such as insects, or through food handlers, contaminated food products or food-processing surfaces, or transfer from sponges, cloths, or utensils. Additionally, the airborne route may contribute to the transmission of certain foodborne pathogens. Complicating epidemiological investigations, multiple transmission routes have been described for some foodborne pathogens. Two types of transmission barriers, primary and secondary, have been described for foodborne pathogens, each of them providing opportunities for preventing and controlling outbreaks. Primary barriers, the most effective sites of prophylactic intervention, prevent pathogen entry into the environment, while secondary barriers prevent the multiplication and dissemination of pathogens that have already entered the environment. Understanding pathogen dynamics, monitoring transmission, and implementing preventive measures are complicated by the phenomenon of superspreading, which refers to the concept that, at the level of populations, a minority of hosts is responsible for the majority of transmission events.

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

Hands can be a vector for transmitting pathogenic microorganisms to foodstuffs and drinks, and to the mouths of susceptible hosts. Hand washing is the primary barrier to prevent transmission of enteric pathogens via cross-contamination from infected persons. Conventional hand washing involves the use of water, soap, and friction to remove dirt and microorganisms. The availability of hand sanitizing products for use when water and soap are unavailable has increased in recent years. The aim of this systematic review was to collate scientific information on the efficacy of hand sanitizers compared with washing hands with soap and water for the removal of foodborne pathogens from the hands of food handlers. An extensive literature search was carried out using three electronic databases: Web of Science, Scopus, and PubMed. Twenty-eight scientific publications were ultimately included in the review. Analysis of this literature revealed various limitations in the scientific information owing to the absence of a standardized protocol for evaluating the efficacy of hand products and variation in experimental conditions. However, despite conflicting results, scientific evidence seems to support the historical skepticism about the use of waterless hand sanitizers in food preparation settings. Water and soap appear to be more effective than waterless products for removal of soil and microorganisms from hands. Alcohol-based products achieve rapid and effective inactivation of various bacteria, but their efficacy is generally lower against nonenveloped viruses. The presence of food debris significantly affects the microbial inactivation rate of hand sanitizers.

Assessment of Enterotoxin Production and Cross-Contamination of Staphylococcus aureus between Food Processing Materials and Ready-To-Eat Cooked Fish Paste

This study evaluated Staphylococcus aureus growth and subsequent staphylococcal enterotoxin A production in tryptone soy broth and on ready-to-eat cooked fish paste at 12 to 37 °C, as well as cross-contamination between stainless steel, polyethylene, and latex glove at room temperature. A model was developed using Barany and Roberts's growth model, which satisfactorily described the suitable growth of S. aureus with R(2)-adj from 0.94 to 0.99. Except at 12 °C, S. aureus cells in TSB presented a lag time lower (14.64 to 1.65 h), grew faster (0.08 to 0.31 log CFU/h) and produced SEA at lower cell density levels (5.65 to 6.44 log CFU/mL) compare to those inoculated on cooked fish paste with data of 16.920 to 1.985 h, 0.02 to 0.23 log CFU/h, and 6.19 to 7.11 log CFU/g, respectively. Staphylococcal enterotoxin type A (SEA) visual immunoassay test showed that primary SEA detection varied considerably among different storage temperature degrees and media. For example, it occurred only during exponential phase at 30 and 37 °C in TSB, but in cooked fish paste it took place at late exponential phase of S. aureus growth at 20 and 25 °C. The SEA detection test was negative on presence of S. aureus on cooked fish paste stored at 12 and 15 °C, although cell density reached level of 6.12 log CFU/g at 15 °C. Cross-contamination expressed as transfer rate of S. aureus from polyethylene surface to cooked fish paste surface was slower than that observed with steel surface to cooked fish paste under same conditions. These results provide helpful information for controlling S. aureus growth, SEA production and cross-contamination during processing of cooked fish paste.

Paper money and coins as potential vectors of transmissible disease

Paper currency and coins may be a public health risk when associated with the simultaneous handling of food and could lead to the spread of nosocomial infections. Banknotes recovered from hospitals may be highly contaminated by Staphylococcus aureus. Salmonella species, Escherichia coli and S. aureus are commonly isolated from banknotes from food outlets. Laboratory simulations revealed that methicillin-resistant S. aureus can easily survive on coins, whereas E. coli, Salmonella species and viruses, including human influenza virus, Norovirus, Rhinovirus, hepatitis A virus, and Rotavirus, can be transmitted through hand contact. Large-scale, 16S rRNA, metagenomic studies and culturomics have the capacity to dramatically expand the known diversity of bacteria and viruses on money and fomites. This review summarizes the latest research on the potential of paper currency and coins to serve as sources of pathogenic agents.

Effect of the food production chain from farm practices to vegetable processing on outbreak incidence

The popularity in the consumption of fresh and fresh-cut vegetables continues to increase globally. Fresh vegetables are an integral part of a healthy diet, providing vitamins, minerals, antioxidants and other health-promoting compounds. The diversity of fresh vegetables and packaging formats (spring mix in clamshell container, bagged heads of lettuce) support increased consumption. Unfortunately, vegetable production and processing practices are not sufficient to ensure complete microbial safety. This review highlights a few specific areas that require greater attention and research. Selected outbreaks are presented to emphasize the need for science-based 'best practices'. Laboratory and field studies have focused on inactivation of pathogens associated with manure in liquid, slurry or solid forms. As production practices change, other forms and types of soil amendments are being used more prevalently. Information regarding the microbial safety of fish emulsion and pellet form of manure is limited. The topic of global climate change is controversial, but the potential effect on agriculture cannot be ignored. Changes in temperature, precipitation, humidity and wind can impact crops and the microorganisms that are associated with production environments. Climate change could potentially enhance the ability of pathogens to survive and persist in soil, water and crops, increasing human health risks. Limited research has focused on the prevalence and behaviour of viruses in pre and post-harvest environments and on vegetable commodities. Globally, viruses are a major cause of foodborne illnesses, but are seldom tested for in soil, soil amendments, manure and crops. Greater attention must also be given to the improvement in the microbial quality of seeds used in sprout production. Human pathogens associated with seeds can result in contamination of sprouts intended for human consumption, even when all appropriate 'best practices' are used by sprout growers.