Foodborne Gastroenteritis Outbreaks Research Articles

Prevalence of extended-spectrum �-lactamase (ESBL)-producing Escherichia coli associated with outbreaks of food-borne gastroenteritis in Tehran

Prevalence of extended-spectrum �-lactamase (ESBL)-producing Escherichia coli associated with outbreaks of food-borne gastroenteritis in Tehran

Foodborne Outbreak by Salmonella enterica Serovar Weltevreden in West Bengal, India.

Foodborne gastroenteritis outbreaks owing to Salmonella enterica serovar Weltevreden (Salmonella Weltevreden) represent a significant global public health problem. In the past two decades, Salmonella Weltevreden has emerged as a dominant foodborne pathogen, especially in South-East Asian countries. This report describes a community foodborne outbreak of gastroenteritis caused by Salmonella Weltevreden in August 2022 following consumption of panipuri from a street vendor in the Polba block in Hooghly district, West Bengal, India. This food item was consumed by 185 people, of whom 129 had acute watery diarrhea with other clinical symptoms and 65 of them were admitted to different District hospitals for treatment. Stool specimens collected from hospitalized cases were positive for S. enterica, and further serotyped as Salmonella Weltevreden. All the Salmonella Weltevreden strains possessed the Salmonella pathogenicity islands associated genes (invA/E, orgA, ttrc, ssaQ, mgtC, misL, spi4D), the enterotoxin (stn), and hyperinvasive locus gene (hilA). Except erythromycin, all the strains were susceptible for commonly used antimicrobials in the treatment of diarrhea. The XbaI-based pulsed-field gel electrophoresis analysis indicated that all the isolates responsible for the recent outbreak were similar, but diverged from other Salmonella Weltevreden that were previously reported in West Bengal. This report indicates that foodborne infection is a major public health concern in India and demands to strengthen capacity-building measures at the local health care levels for linking causative agents of outbreaks.

Characteristics of Gastroenteritis Outbreaks Investigated in Singapore: 2018-2021.

There is a need to study the characteristics of outbreaks via Singapore's outbreak surveillance system to understand and identify the gaps in food safety for targeted policy interventions due to the increasing trend in gastroenteritis outbreaks and consequential increase in foodborne-related deaths and economic burden on public health systems worldwide. A total of 171 gastroenteritis outbreaks were investigated in Singapore from January 2018 to December 2021. This study analyzed the annual trend of investigated gastroenteritis outbreaks, the proportion of outbreaks by implicated sources of food, and the proportion of the type of pathogens identified from human cases, food samples, and environmental swabs collected from outbreak investigations. Among the foodborne gastroenteritis outbreaks (n = 121) investigated in Singapore, approximately 42.1% of the outbreaks had food prepared by caterers, 14.9% by restaurants, and 12.4% had food prepared by in-house kitchens. Clostridium perfringens and Salmonella were the most common causative pathogens in foodborne outbreaks throughout the analysis period. The food samples and environmental swabs collected were mostly detected for Bacillus cereus. Norovirus was the most common causative pathogen in non-foodborne outbreaks and was mainly attributable to preschools. This highlights the importance of monitoring and educating the catering industry and preschools to prevent future outbreaks.

Vibrio-Sequins - dPCR-traceable DNA standards for quantitative genomics of Vibrio spp

BackgroundVibrio spp. are a diverse group of ecologically important marine bacteria responsible for several foodborne outbreaks of gastroenteritis around the world. Their detection and characterization are moving away from conventional culture-based methods towards next generation sequencing (NGS)-based approaches. However, genomic methods are relative in nature and suffer from technical biases arising from library preparation and sequencing. Here, we introduce a quantitative NGS-based method that enables the quantitation of Vibrio spp. at the limit of quantification (LOQ) through artificial DNA standards and their absolute quantification via digital PCR (dPCR).ResultsWe developed six DNA standards, called Vibrio-Sequins, together with optimized TaqMan assays for their quantification in individually sequenced DNA libraries via dPCR. To enable Vibrio-Sequin quantification, we validated three duplex dPCR methods to quantify the six targets. LOQs were ranging from 20 to 120 cp/µl for the six standards, whereas the limit of detection (LOD) was ~ 10 cp/µl for all six assays. Subsequently, a quantitative genomics approach was applied to quantify Vibrio-DNA in a pooled DNA mixture derived from several Vibrio species in a proof-of-concept study, demonstrating the increased power of our quantitative genomic pipeline through the coupling of NGS and dPCR.ConclusionsWe significantly advance existing quantitative (meta)genomic methods by ensuring metrological traceability of NGS-based DNA quantification. Our method represents a useful tool for future metagenomic studies aiming at quantifying microbial DNA in an absolute manner. The inclusion of dPCR into sequencing-based methods supports the development of statistical approaches for the estimation of measurement uncertainties (MU) for NGS, which is still in its infancy.

A foodborne outbreak of gastroenteritis caused by Norovirus and Bacillus cereus at a university in the Shunyi District of Beijing, China 2018: a retrospective cohort study

BackgroundOn September 4, 2018, a boarding school in the Shunyi District of Beijing, China reported an outbreak of acute gastroenteritis. At least 209 suspected students caused of diarrhea and vomiting. The case was investigated, and control measures were taken to prevent further spread.MethodsA retrospective cohort study was conducted among the school students and staff in order to test hypothesis that high risk of food served at the school canteen. We collected information on demographics, refectory records, person to person transmission by uniform epidemiological questionnaire. Risk ratios (RR) and 95% confidence intervals (CI) were calculated. Stool specimens of cases and canteen employees, retained food, water, and environmental swabs were investigated by laboratory analysis.ResultsWe identified 209 cases (including 28 laboratory-confirmed cases) which occurred from August 29 to September 10. All cases were students, and the average age was 20, 52% were male. The outbreak lasted for 13 days, and peaked on September 5. Consumption of Drinks stall and Rice flour stall on September 1 (RR:3.4, 95%CI:1.5–7.8, and RR:7.6, 95%CI:2.8–20.2), Rice flour stall and Fish meal stall on September 2 (RR:4.0, 95%CI:1.2–13.6, and RR:4.6, 95%CI:1.7–12.5), muslim meal stall on September 4 (RR:2.7, 95%CI:1.3–5.4), Barbeque stall on September 5 (RR:3.0, 95%CI:1.2–7.0) were independently associated with increased risk of disease within the following 2 days. Among 35 specimens of rectal swabs or feces from students, 28 specimens were positive. Norovirus GI.6 alone was detected in 23 specimens, Bacillus cereus alone in 3 specimens and both norovirus GI.6 and Bacillus cereus in 2 specimens. Ten specimens of rectal swabs from canteen employees were positive for norovirus GI, and 2 specimens were positive for Bacillus cereus. Four retained food specimens were positive for Bacillus cereus, and environmental samples were negative for any viruses or bacteria.ConclusionOur investigation indicated that canteen employees were infected by two pathogens (norovirus and Bacillus cereus) and transmission may have been possible due to unhygienic practices. Student consumption of food or drink at high-risk stalls was determined as the probable cause of the outbreak.

Involvement of Egyptian Foods in Foodborne Viral Illnesses: The Burden on Public Health and Related Environmental Risk Factors: An Overview

Foodborne viral diseases are a major public health threat and pose a huge burden on the economies of both developed and developing countries. Enteric viruses are the causative agents of most foodborne illnesses and outbreaks. Egypt is classified by WHO among the regions with intermediate to high endemicity for various enteric viruses. This is manifested by the high prevalence rates of different enteric virus infections among Egyptian population such as Hepatitis A and E viruses, human rotaviruses, human noroviruses, human astroviruses, and human adenovirus. Recently, a number of foodborne gastroenteritis and acute hepatitis outbreaks have occurred in the US, Canada, Australia, and the European Union countries. Some of these outbreaks were attributed to the consumption of minimally processed foods imported from Egypt indicating the possibility that Egyptian foods may also be partially responsible for high prevalence of enteric virus infections among Egyptian population. In the absence of official foodborne-pathogen surveillance systems, evaluating the virological safety of Egyptian foods is a difficult task. In this review, we aim to provide a preliminary evaluation of the virological safety of Egyptian foods. A comprehensive review of prevalence studies on enteric virus infections shows hyperendemicity of several enteric viruses in Egypt and provides strong evidence of implication of Egyptian foods in these infections. We also address possible environmental risk factors that may lead to the contamination of Egyptian foods with enteric viruses. In addition, we describe potential obstacles to any plan that might be considered for improving the virological safety of Egyptian foods.

Outbreak of foodborne gastroenteritis in a school, Kohima District, Nagaland, India, September 2017

Purpose: A private hospital in Kohima reported 41 admitted cases of diarrhoea to State Surveillance Unit Nagaland on September 2, 2017. Our team started investigation on September 2, 2017 to describe the epidemiological characteristics of outbreak and to determine the associated risk factors. Methods & Materials: We defined a case as “diarrhoea (>3 stools in 24 hours) or vomiting in a child studying in a private school, Kohima from August 29, 2017 to September 8, 2017”. We did a classroom to classroom survey for cases and conducted a retrospective cohort study on people who attended or ate from school farewell event on September 1, 2017. We observed exposure of different food items and risk factors involved. We collected four stool samples for testing pathogens. Results: We identified 209 cases with an attack rate of 77%. Among them, 154 were hospitalised. There were no deaths. Attack rate was highest in age group of 16-25 years (73%). Females (59%) were more affected. Among identified cohort of 271 people, 249 attended the farewell and 187 fell ill, 22 did not attend but ate food brought home. Risk of gastroenteritis was 4.5 times (95% CI = 1.8-11.0) among those who ate chocolate cake with coffee toppings and 1.2 times (95% CI = 1.0-1.3) among females than in males. Of the four stool samples, one tested positive for Escherichia Coli, one for Bacillus Pseudomonas and two for Staphylococcus Aureus. Conclusion: An outbreak of gastroenteritis due to mixed bacterial infection occurred following a school farewell event having strong association with food item chocolate cake with coffee toppings. We recommend Information, Education and Communication activities regarding proper cooking and food storage and timely collection of appropriate samples for testing.

Surveillance of norovirus contamination in commercial fresh/frozen berries from Heilongjiang Province, China, using a TaqMan real-time RT-PCR assay

Norovirus (NoV), a major food-borne virus, causes non-bacterial acute gastroenteritis in humans. Berries are generally harvested from low-growing bushes by hand and are minimally processed before being sold to consumers. Therefore, the consumption of berries has been linked to numerous food-borne gastroenteritis outbreaks caused by NoV in many countries. We performed a survey of NoV contamination in commercial fresh/frozen berry fruits collected from 2016 to 2017 in the Heilongjiang Province, the main berry-producing area in China, using a TaqMan-based real-time reverse transcription-PCR assay. Among 900 frozen and 900 fresh domestic retail berry samples, the prevalence of NoV was 9% (81/900) and 12.11% (109/900), including 35.80% (29/81) and 29.36% (32/109) of genotype GI alone, 54.32% (44/81) and 60.55% (66/109) of GII alone, and 9.88% (8/81) and 10.09% (11/109) of both GI and GII, respectively. No NoV was detected among the 677 frozen berry samples for export. Thus, the occurrence of NoV contamination was significantly higher in domestic berries than in exported berries and higher in fresh berries than in frozen berries. This study highlights the need for further risk surveillance for NoV contamination in berries produced in the Heilongjiang Province and recommends region-extended monitoring of retail berries for NoV.

A foodborne outbreak of gastroenteritis caused by Vibrio parahaemolyticus associated with cross-contamination from squid in Korea.

OBJECTIVESWater-borne diseases caused by Vibrio parahemolyticus are often known to cause gastritis when raw or undercooked seafood is eaten. It is very rare that Vibrio gastritis caused by ingesting non-seafood products occurs on a large scale. On September 19, 2017, a large-scale Vibrio gastritis occurred after the city residents consumed food at a bazaar held in a welfare center in Jungnang-gu, Seoul.METHODSThe total number of visitors was approximately 299, and 237 (79.3%) of them showed symptoms. Among those who showed symptoms, 116 (48.9%) consulted the hospital, and 53 (45.6%) were hospitalized. Among the 299 exposed individuals, 174 (58.1%) responded to this survey: 163 (93.6%) with and 11 (6.4%) without symptoms. This study was retrospectively conducted by investigating the exposed individuals. To investigate the spread of infection, medical staff of hospitals in the epidemic area were interviewed, exposed individuals surveyed, microbiological testing conducted, and ingredient handling and cooking processes investigated.RESULTSA total of 237 individuals, including 6 food handlers, were affected (prevalence, 79.2%). During the microbiological testing, V. parahemolyticus was found in 34 patients and 4 food handlers. In the consumption analysis, the relative risk of kimbap was 6.79 (confidence interval 1.10 to 41.69). In-depth investigation found that squid, an ingredient of Korean pancake, and egg sheets, an ingredient of kimbap, were prepared using the same cutting board and knife, which were thought to be the cause of cross-contamination that led to a large-scale outbreak of Vibrio gastritis.CONCLUSIONSA recent large-scale outbreak of Vibrio gastritis occurred due to the cross-contamination with kimbap during the preparation process of squid rather than the actual consumption of seafood. Thus, a more stringent hygiene management is necessary during the processing and management of food to prevent infections associated with V. parahemolyticus.

Foodborne outbreak of gastroenteritis caused by Staphyilococcal enterotoxin in Northern Italy

Foodborne outbreak of gastroenteritis caused by Staphyilococcal enterotoxin in Northern Italy

Development of a rapid and sensitive electrochemical biosensor for detection of human norovirus via novel specific binding peptides

Human noroviruses cause acute foodborne gastroenteritis outbreaks worldwide. In this study, a highly sensitive and selective electrochemical biosensor was fabricated for the detection of human norovirus using novel peptides as recognition elements. The electrochemical biosensor was fabricated by assembling of eight novel peptides separately on the gold electrode and investigated their efficiencies for sensing human noroviruses. Among eight peptides, NoroBP peptide coated onto the gold electrode exhibited a high binding affinity towards human noroviruses, resulting a progressive decrease in current signals with increasing concentration of human norovirus (0–105 copies/mL). As a result, NoroBP-nonFoul(FlexL)2-coated gold electrode acts an efficient electrochemical biosensor for highly selective detection of human norovirus with a detection limit of 1.7 copies/mL, which is 3-fold lower than the reported methods. The developed electrochemical biosensor was successfully applied to detect human norovirus prepared by standard procedure from oyster, which suggests that the developed biosensor can be used as a very sensitive and selective point-of-care bioanalytical platform for the detection of human norovirus in various food samples.

Identification of Sapovirus GV.2 in a Suspected Foodborne Gastroenteritis Outbreak Using Next-Generation Sequencing

Identification of Sapovirus GV.2 in a Suspected Foodborne Gastroenteritis Outbreak Using Next-Generation Sequencing

Research on the contamination levels of norovirus in food facilities using groundwater in South Korea, 2015–2016

Norovirus (NoV) is a major pathogenic virus that is responsible for foodborne and waterborne gastroenteritis outbreaks. Groundwater is an important source of drinking water and is used in agriculture and food manufacturing processes. This study investigated norovirus contamination of groundwater treatment systems at 1360 sites in seven metropolitan areas and nine provinces in 2015–2016. Temperature, pH, residual chlorine, and turbidity content were assessed to analyze the water quality. In 2015, six sites were positive for the presence of NoV (0.88%) and in 2016, two sites were positive (0.29%); in total, NoV was detected in 8 of the 1360 sample sites (0.59%) investigated. Identified genotypes of NoV in groundwater included GI.5, 9 and GII.4, 6, 13, 17, and 21. GII.17 was the most prevalent genotype in treated groundwater used in the food industry. This dominance of GII.17 was corroborated by NoV infection outbreak cases and the results of a survey of coastal waters in South Korea in 2014–2015. Although a low detection rate was observed in this study, NoV is a pathogen that can spread extensively. Therefore, it is necessary to periodically monitor levels of norovirus which is responsible for food poisoning in groundwater. This is a first report to reveal epidemic genotype shift of norovirus in groundwater treatment system of food facilities in South Korea. Our results may contribute to the enhancement of public health and sanitary conditions by providing molecular epidemiological information on groundwater NoV.

A Bacterial Surface Display System Expressing Cleavable Capsid Proteins of Human Norovirus: A Novel System to Discover Candidate Receptors.

Human noroviruses (HuNoVs) are the dominant cause of food-borne outbreaks of acute gastroenteritis. However, fundamental researches on HuNoVs, such as identification of viral receptors have been limited by the currently immature system to culture HuNoVs and the lack of efficient small animal models. Previously, we demonstrated that the recombinant protruding domain (P domain) of HuNoVs capsid proteins were successfully anchored on the surface of Escherichia coli BL21 cells after the bacteria were transformed with a plasmid expressing HuNoVs P protein fused with bacterial transmembrane anchor protein. The cell-surface-displayed P proteins could specifically recognize and bind to histo-blood group antigens (HBGAs, receptors of HuNoVs). In this study, an upgraded bacterial surface displayed system was developed as a new platform to discover candidate receptors of HuNoVs. A thrombin-susceptible “linker” sequence was added between the sequences of bacterial transmembrane anchor protein and P domain of HuNoV (GII.4) capsid protein in a plasmid that displays the functional P proteins on the surface of bacteria. In this new system, the surface-displayed HuNoV P proteins could be released by thrombin treatment. The released P proteins self-assembled into small particles, which were visualized by electron microscopy. The bacteria with the surface-displayed P proteins were incubated with pig stomach mucin which contained HBGAs. The bacteria-HuNoV P proteins-HBGAs complex could be collected by low speed centrifugation. The HuNoV P proteins-HBGAs complex was then separated from the recombinant bacterial surface by thrombin treatment. The released viral receptor was confirmed by using the monoclonal antibody against type A HBGA. It demonstrated that the new system was able to capture and easily isolate receptors of HuNoVs. This new strategy provides an alternative, easier approach for isolating unknown receptors/ligands of HuNoVs from different samples including mammalian cell lines, oysters, and fresh produce.

Norovirus contamination in retail oysters from Beijing and Qingdao, China

The consumption of raw oyster has been linked to numerous foodborne gastroenteritis outbreaks caused by norovirus (NoV) in different countries of the world, including in China. This study investigated the prevalence of NoV and contamination levels in retail oysters taken from markets in Beijing and Qingdao in China. The oysters were collected monthly from seafood markets between September 2015 and September 2016 (13 months) in both cities. The digestive glands of these oysters were dissected and NoV particles were extracted. Viral RNA was detected using a TaqMan-based real time one-step reverse transcription-PCR (qRT-PCR) protocol. Of total 672 oyster samples assessed, 652 were considered to be valid for inclusion in the study. The prevalence of NoV was 20.71% (135/652), and this included 21.48% (29/135) of the samples that were positive for the GI strain alone, 62.96% (85/135) contained the GII strain alone and 15.56% (21/135) were mixed with GI and GII, respectively. A total of 68 NoV-positive samples were quantified by qRT-PCR and values obtained ranged from 3.55 × 103 to 1.45 × 106 genomic copies per g digestive tissue. The NoV contamination in retail oysters fluctuated with the sampling month and peaks of contamination occurred in February (49.12%) and March (55.36%) 2016, respectively. Considering some of the oysters were consumed as raw or half-cooked in China, as a risk reduction measure these oysters should be well heated prior to consumption. Furthermore, successive and region-extended monitoring in retail oysters for NoV as well as risk communication is recommended.

The major targets of acute norovirus infection are immune cells in the gut-associated lymphoid tissue.

Noroviruses are the leading cause of food-borne gastroenteritis outbreaks and childhood diarrhoea globally, estimated to be responsible for 200,000 deaths in children each year 1-4 . Thus, reducing norovirus-associated disease is a critical priority. Development of vaccines and therapeutics has been hindered by the limited understanding of basic norovirus pathogenesis and cell tropism. While macrophages, dendritic cells, B cells and stem-cell-derived enteroids can all support infection of certain noroviruses in vitro 5-7 , efforts to define in vivo norovirus cell tropism have generated conflicting results. Some studies detected infected intestinal immune cells 8-12 , other studies detected epithelial cells 13 , and still others detected immune and epithelial cells 14-16 . Major limitations of these studies are that they were performed on tissue sections from immunocompromised or germ-free hosts, chronically infected hosts where the timing of infection was unknown, or following non-biologically relevant inoculation routes. Here, we report that the dominant cellular targets of a murine norovirus inoculated orally into immunocompetent mice are macrophages, dendritic cells, B cells and T cells in the gut-associated lymphoid tissue. Importantly, we also demonstrate that a norovirus can infect T cells, a previously unrecognized target, in vitro. These findings represent the most extensive analyses to date of in vivo norovirus cell tropism in orally inoculated, immunocompetent hosts at the peak of acute infection and thus they significantly advance our basic understanding of norovirus pathogenesis.

Norovírus em alimentos

Introduction: Noroviruses (NoV) are important causative agents of foodborne gastroenteritis outbreaks associated with the consumption of fruits, leafy vegetables, bivalve molluscs and delicatessen foods. The establishment of laboratory surveillance networks in different continents has demonstrated increased epidemiological importance of those viruses. In Brazil, the NoV infection is considered an important public health issue with socioeconomic burden, but the investigation of these viruses in foodborne outbreaks is still restricted to research laboratories. NoV infections have become more known especially with the consolidation of the cruise ship market in the country since 2004. Objective: This study aims to present advances related to NoV research in foods, highlighting features of this pathogen and strategies for its detection in these matrices. Method: An integrative review, collecting scientific articles with the objective of dealing with the main aspects of NoV, was carried out. Results: A broad literature review was performed, describing the main results in the literature and discussing aspects such as foodborne diseases, viruses as food contaminants, stability and disinfection, foodborne outbreaks associated with NoV, food associated with NoV contamination, NoV concentration and detection methods in food, risk assessment studies and prevention and control. Conclusions: records of foodborne outbreaks associated with NoV and the increasing genetic diversity of these viruses reinforce the need for laboratory and epidemiological surveillance, especially in developing countries, such as Brazil.

Investigation of a food-borne outbreak of gastroenteritis in a school canteen revealed a variant of sapovirus genogroup V not detected by standard PCR, Sollentuna, Sweden, 2016.

A food-borne outbreak of gastroenteritis with more than 650 suspected cases occurred in April 2016 in Sollentuna, Sweden. It originated in a school kitchen serving a total of 2,700 meals daily. Initial microbiological testing (for Campylobacter, Salmonella, Shigella, Yersinia, Giardia, Cryptosporidium, Entamoeba histolytica, adeno-, astro-, noro-, rota- and sapovirus) of stool samples from 15 symptomatic cases was negative, despite a clinical presentation suggestive of calicivirus. Analyses of the findings from both the Sollentuna municipality environmental team and a web-based questionnaire suggested that the source of the outbreak was the salad buffet served on 20 April, although no specific food item could be identified. Subsequent electron microscopic examination of stool samples followed by whole genome sequencing revealed a variant of sapovirus genogroup V. The virus was not detected using standard PCR screening. This paper describes the epidemiological outbreak investigation and findings leading to the discovery.

Erratum to: The Presence of Norovirus and Adenovirus on Environmental Surfaces in Relation to the Hygienic Level in Food Service Operations Associated with a Suspected Gastroenteritis Outbreak.

Norovirus (NoV) gastroenteritis outbreaks appear frequently in food service operations (FSOs), such as in restaurants and canteens. In this study the presence of NoV and adenovirus (AdV) genomes was investigated on the surfaces of premises, especially in kitchens, of 30 FSOs where foodborne gastroenteritis outbreaks were suspected. The objective was to establish a possible association between the presence of virus genomes on surfaces and a visual hygienic status of the FSOs. NoV genome was found in 11 and AdV genome in 8 out of 30 FSOs. In total, 291 swabs were taken, of which 8.9% contained NoV and 5.8% AdV genome. The presence of NoV genomes on the surfaces was not found to associate with lower hygiene level of the premises when based on visual inspection; most (7/9) of the FSOs with NoV contamination on surfaces and a completed evaluation form had a good hygiene level (the best category). Restaurants had a significantly lower proportion of NoV-positive swabs compared to other FSOs (canteens, cafeteria, schools etc.) taken together (p = 0.00014). The presence of a designated break room for the workers was found to be significantly more common in AdV-negative kitchens (p = 0.046). Our findings suggest that swabbing is necessary for revealing viral contamination of surfaces and emphasis of hygiene inspections should be on the food handling procedures, and the education of food workers on virus transmission.

The Presence of Norovirus and Adenovirus on Environmental Surfaces in Relation to the Hygienic Level in Food Service Operations Associated with a Suspected Gastroenteritis Outbreak

Norovirus (NoV) gastroenteritis outbreaks appear frequently in food service operations (FSOs), such as in restaurants and canteens. In this study the presence of NoV and adenovirus (AdV) genomes was investigated on the surfaces of premises, especially in kitchens, of 30 FSOs where foodborne gastroenteritis outbreaks were suspected. The objective was to establish a possible association between the presence of virus genomes on surfaces and a visual hygienic status of the FSOs. NoV genome was found in 11 and AdV genome in 8 out of 30 FSOs. In total, 291 swabs were taken, of which 8.9% contained NoV and 5.8% AdV genome. The presence of NoV genomes on the surfaces was not found to associate with lower hygiene level of the premises when based on visual inspection; most (7/9) of the FSOs with NoV contamination on surfaces and a completed evaluation form had a good hygiene level (the best category). Restaurants had a significantly lower proportion of NoV-positive swabs compared to other FSOs (canteens, cafeteria, schools etc.) taken together (p = 0.00014). The presence of a designated break room for the workers was found to be significantly more common in AdV-negative kitchens (p = 0.046). Our findings suggest that swabbing is necessary for revealing viral contamination of surfaces and emphasis of hygiene inspections should be on the food handling procedures, and the education of food workers on virus transmission.