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Health risk assessment of Staphylococcus aureus and Salmonella from the consumption of street foods in Ethiopia

BMC Infectious Diseases volume 25, Article number: 576 (2025) Cite this article

Abstract

Introduction

Due to inadequate hygienic practices and improper handling, street foods may become contaminated, posing a significant risk for various foodborne diseases. This study aimed to determine the health risks to consumers from consuming street foods contaminated with Staphylococcus aureus and Salmonella.

Method

A cross-sectional study design was used from December 2022 to February 2023 on the street foods of Addis Ababa, Hawassa, Dire Dawa, and Jimma towns. A total of 525 street foods were taken from 175 street food vending stalls. A stratified sampling technique was used to select vending stalls. A questionnaire was used to collect the data which were analyzed via SPSS-25. Food samples were analyzed at the Ethiopian Public Health Institute food microbiology laboratory using the standard microbiological methods used for the isolation, enumeration, and identification of bacteria. A quantitative microbial risk assessment was used to assess and determine the risk of infection using a deterministic approach.

Result

The frequent, average, and occasional consumers of street foods were 26.9%, 52.6%, and 20.5% respectively. The prevalence of Staphylococcus aureus was 43.4% whereas 25.7% for Salmonella species. The risk of infection from S. aureus was higher than Salmonella. The mean annual risk of S aureus infection of consumers was 100%, 99%, and 93% for frequent, average, and occasional consumers respectively. A total of 32.6% of the sampled foods had greater than 104 CFU/g a colony count of Staphylococcus aureus whereas in 25.7% of the samples Salmonella exceeded the safety standards and made the food unfit for consumption.

Conclusion

The results highlighted the significant risk of infection with Staphylococcus aureus and Salmonella in Ethiopian street foods, and revealed that frequent consumption of street foods was associated with a high risk of infection. This urges improved hygiene practices to mitigate hazards and protect public health.

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Introduction

Street foods are ready-to-eat foods and beverages prepared and/or sold by vendors and hawkers, especially in streets and other similar public places [1]. As urbanization increases worldwide, the consumption of meals outside the home is becoming more common. Street foods play an important role in meeting the food needs of urban dwellers in many developing-country cities and towns [2]. It feeds millions of people every day with a diverse range of low-cost and easily accessible foods [3]. Food safety is a significant issue with street foods, as they are often prepared and sold in unsanitary environments [4, 5]. In addition, the traditional processing methods that are used in preparation, inappropriate holding temperatures, and poor personal hygiene of food handlers are some of the main causes of contamination of street foods [2, 3, 6].

Food safety is a critical public health concern within communities [7]. Studies on street food safety in developing countries have revealed the presence of different species of pathogens as well as favorable conditions to allow their proliferation. Staphylococcus aureus and Salmonella are the common foodborne pathogens associated with street foods in different parts of the world [3, 4, 8, 9]. This happens due to the use of nutritious ingredients in processing fast food [10], and is associated with contamination that has been directly introduced into the food by food handlers through coughing and sneezing [11].

Staphylococcus aureus, which is commonly present in the environment, coexists as a commensal organism within the human body and is a well-recognized zoonotic pathogen transmitted through food, often swiftly developing resistance to antimicrobial agents [7, 11]. It remains one of the primary bacteria implicated in human diseases [12]. As major bacterial culprits of food-borne illnesses globally [7]. Staphylococcus aureus is part of the normal skin microbiota in both animals and humans, with a carriage rate ranging from 20 to 30% in healthy individuals [13].

Risk analysis is used to estimate the risks to human health, identify and implement effective risk-control measures, and communicate with stakeholders about the risks and the implemented measures [10]. Microbiological risk assessment is a systematic method for determining and characterizing the risk of biological hazards in food [14]. It can be performed qualitatively, semi-quantitatively, or quantitatively [1]. Quantitative microbiological risk assessment (QMRA), which is one of the three components of the risk analysis process, is a scientific-based process consisting of four components; hazard identification, hazard characterization (dose-response), exposure assessment, and risk characterization which together provide numerical expressions of risk [12, 15, 16]. This holistic approach to food safety uses process risk models to simulate consumer exposure and response to pathogens that contaminate food produced by specific farm-to-table scenarios [17]. It is a relatively new scientific field that can approximate the impact of contaminated food on consumer health by connecting data on food-borne diseases and information on food production to consumption [15, 18].

There have been few studies on the safety and quality of Ethiopian street foods, with the majority of them focused on assessing hygienic practices and the isolation of pathogens and their susceptibility patterns to various antibiotic drugs [8, 19,20,21,22,23,24]. However, none of them have attempted to assess the risk of infection from the consumption of Staphylococcus aureus and Salmonella contaminated street foods. Hence, the purpose of this study was to assess the health risks to street food consumers from S aureus and Salmonella contaminated street food.

Materials and methods

Study design, study period, and settings

A Laboratory-based cross-sectional study design was used from December 2022 to February 2023 in four selected towns of Ethiopia, namely Addis Ababa, Dire Dawa, Hawassa, and Jimma.

Sample size determination and sampling procedure

The sample size was determined via the single population proportion formula by considering the 95% CI, corresponding to a standard score of 1.96, margin of error (d) 0.05, and 11.7% prevalence (P) of Staphylococcus aureus on street food [19] including a 10% non-response rate and the sample size was one hundred seventy five street food vending stalls. Proportional allocation of street food vendors to the number of population found in the selected cities was used, and stratified sampling was used to locate the vending stalls while a convenient sampling technique was used to select a person who consumes one of the street food items from the selected street food vending stall [25].

Bacteria culture and enumeration

Sample collection

The three selected food items from a single vending stall were collected aseptically, kept in labeled sterile polyethylene plastic bags on ice, and immediately transported to Hawassa, Jimma, Haramaya Universities, medical laboratory departments, and Ethiopian Public Health Institute Laboratories. On arrival, samples were registered, and given a unique code [25].

Media Preparation

Mannitol-salt agar (MSA), Nutrient agar, and Buffered Peptone water (BPW) all from Oxoid Ltd, England, were prepared according to manufacturer’s instructions, and sterilized by autoclaving at 121oC for 15 min.

Food sample processing

The food samples were prepared for analysis following the standard methods for isolation, and detection of bacteria from food samples as described by Moges et al. (2024).

Enumeration and Isolation of Staphylococcus aureus

Staphylococcus aureus was isolated and enumerated by the pour plate method via Mannitol-salt agar (MSA). After 24 h of incubation at 37oC, golden yellow colonies were counted and recorded as presumptive Staphylococcus species in CFU/g using the colony counter. Presumptive Staphylococcus species colonies on MSA were sub cultured onto freshly prepared nutrient agar plates and confirmed by Gram staining and coagulase tests with rabbit plasma. Colonies on mannitol salt agar that were Gram positive and coagulase-positive were taken as Staphylococcus aureus [26].

Enumeration and isolation of Salmonella

The bacteriological examination for Salmonella followed the food chain microbiology guidelines, specifically the horizontal method for detection, enumeration, and serotyping of Salmonella, as referenced by Gebeyehu et al. (2022). A 25 g of sample food were aseptically mixed with 225 ml of 0.1% buffered peptone water (OXOID, CM059) and incubated at 37 °C for 24 h. In the secondary enrichment phase, a 0.1 ml aliquot was transferred to 10 ml of Rappaport-Vassiliadis with soya (RVS) broth and incubated at 41.5 °C for 24 h. For the selective stage, 10 µl of the enriched sample was plated onto xylose lysine deoxycholate (XLD) agar and incubated at 35 °C for 24 h, after which the plates were examined for Salmonella colonies. Typical Salmonella colonies appear as pink with or without black centers on XLD agar. Three to five typical colonies were selected and streaked onto tryptone soya agar, then incubated at 37 °C for 18–24 h for further biochemical identification. The biochemical tests followed standard protocols, including indole, methyl red, urease, citrate utilization, triple sugar iron (TSI), lysine decarboxylase, and hydrogen sulfide production tests [4, 25, 27].

Microbial risk assessment

Risk assessment is a process that involves evaluating the health effects of foodborne pathogens, using quantitative or qualitative methods based on available resources and the background of involved parties [28]. For this study, the quantitative microbial risk assessment technique was used following WHO standards, which call for hazard characterization, hazard identification, exposure assessment, and risk characterization [29]. As described by [30] owing to the absence of full data and the multifaceted nature of processing and handling of food items throughout the food chain, it is sometimes possible to focus on the end product to conduct risk assessment. Hence, this research focuses only on processed ready-to-eat food items.

Hazard identification

It is the identification of biological, chemical, and physical agents capable of causing adverse health effects that may be present in a particular food or group of foods [29]. The indicator microorganisms for this research were Staphylococcus aureus and Salmonella as they are commonly found in street food samples from Ethiopia and other countries [8, 10, 19].

Staphylococcus aureus is one of the major pathogens related to outbreaks of foodborne illness [31]. This gram-positive, catalase, and coagulase-positive coccus can thrive across a wide range of pH values, temperatures, and water activities as low as 0.83 [12]. Due to its adaptability to these diverse conditions, S. aureus is commonly found in various foods, particularly ready-to-eat items, making them significant reservoirs of the bacteria. Additionally, S. aureus is a part of the normal skin microbiota in both animals and humans, with a carriage rate of 20 to 30% in healthy individuals [32]. Economically, S. aureus is considered one of the most impactful pathogens. It is associated with staphylococcal food poisoning, which typically results in a self-limiting but acutely intense illness. The pathogen is also capable of causing a broad spectrum of infections and foodborne diseases. Its presence in food is often linked to cross-contamination and poor handling practices during food preparation [15, 33].

Salmonella are motile, gram-negative bacilli that can infect or colonize humans. These bacteria produce hydrogen sulfide and are acid-labile, meaning that they are sensitive to acidic environments, and can live both inside and outside cells. Salmonella can cause cross-infections between humans and animals, leading to various clinical conditions such as gastroenteritis, enteric fever, bacteremia, and a chronic carrier state. Enteric fever is caused by specifically Salmonella typhi and Salmonella paratyphi, whereas other strains of Salmonella are referred to as non-typhoidal [27, 34, 35].

Exposure assessment

It is the qualitative or quantitative evaluation of the likely intake of biological agents via food and exposure from other sources if relevant [29]. The exposure scenarios were assessed as frequent consumption as consumed daily, average consumption once a week, and occasional consumption once in month [30]. The number of exposure days per year was taken as 365, 52, and 12 days for frequent, average, and occasional consumers respectively. The average amount of selected food consumed per person per day was weighted, and the other inputs are shown in table one. The dose of the model organisms used for the dose-response assessment was obtained from the exposure assessment via the mathematical relationship [36].

d = q x W.

where: d = quantity of microorganisms consumed per serving,

q = quantity of microorganisms per gram of selected food item (CFU/g).

W = the weight of selected food item consumed per serving.

Hazard characterization (dose response assessment)

It is the qualitative or quantitative evaluation of the nature of the adverse health effects and hazards that may be present in food [29]. S. aureus bacteria are responsible for approximately 100,000 infectious disease cases, with an annual mortality rate of 20–30% in the United States and this pathogen has been the cause of 171 outbreaks of foodborne illness in the past decade in Korea [31, 37]. The intoxication dose of S. aureus is less than 1000 ng, a level that is reached when it exceeds 100,000 organisms/g in food, indicative of unsanitary conditions. In highly sensitive people, ingestion of 100–200 ng of enterotoxin can cause symptoms of staphylococcal food poisoning [38]. This results in minor skin infections such as boils and a range of food poisoning symptoms. These symptoms, which include nausea, sweating, dizziness, vomiting, hypothermia, stomach cramps, weakness, lethargy, and diarrhea, typically appear within six hours after ingesting contaminated food [11].

Typhoid fever is notably common in South Asia and sub-Saharan Africa, with incidence rates exceeding 100 per 100,000 people each year [34, 35]. In the European Union, Salmonella ranks as the second most frequent cause of gastrointestinal outbreaks. In France, Salmonella is responsible for nearly half of the 1,500 annual foodborne infections, primarily originating from poultry meat, while usually self-limiting, severe cases in immunocompromised individuals require antibiotics [35, 39]. The exponential dose-response model was used to assess the dose-response rate to predict the probability of S. aureus infection. Mathematically, the probability of infection for the exponential model used is given as: [36].

P = 1- e – r.d.

where: P is the probability of infection

d is the dose (CFU) of microorganisms consumed.

r is a dimensionless infectivity constant (the probability for one organism to successfully initiate an infection).

Risk characterization

It is a qualitative or quantitative estimation, including attendant uncertainties, of the probability of occurrence and severity of known or potential adverse health effects in a given population on the basis of hazard identification, hazard characterization, and exposure assessment [29].

Risk in this case is defined as the likelihood of the occurrence of an illness and the likely magnitude of its consequences. The risk was assessed on the basis of the identified hazard concentration to which individuals were exposed. The annual probability was calculated using the number of exposure events per year. The annual exposures were analyzed as follows; frequent (365 days), 52 days average, and occasional 12 days. The risk was obtained via the following formula [36], and using the input parameters as described in Table 1.

P (a) = 1-(1-P(d)) n.

P (a) = the annual probability of infection per person per year.

P(d) = the daily probability of infection.

n = the annual exposure frequency (days).

Table 1 Input parameters for quantitative microbial risk assessment, 2024 Ethiopia
Full size table

Data collection

Socio-demographic data of the consumers were collected via an interviewer-administered questionnaire (attached as a supplementary file) and the identified food items were also purchased from each street food vendors. From a single vending stall Sambussa, Bobolino/biscuit, and Ambasha were taken randomly for the analysis. All food samples were collected and stored in labeled sterile polyethylene plastic bags and kept in an icebox, after which they were immediately transported to Hawassa, Jimma, Haramaya Universities, medical laboratory departments, and Ethiopian Public Health Institute Laboratories. On arrival, samples were registered, given a special code, and stored at 4 °C until testing.

Data analysis

The data were entered into SPSS 25.0 for descriptive socio-economic status analysis. For microbial risk assessment, a deterministic quantitative microbial risk assessment was used.

Description of the food items

Sambussa

also known as samosa, is a well-known snack in Ethiopia and many other countries around the world that is made up of wheat dough. The dough is prepared flatly and the other ingredients rolled in triangle shape within it and roasted in deep frying oil. The ingredients are wheat dough, salt, oil, chopped onions and red pepper, cooked rice, cooked lentils, Sambussas are typically deep-fried until they are golden brown and crispy on the outside, with a deliciously soft and flavorful filling on the inside. They commonly serve as appetizers, snacks, or street food and are enjoyed across Ethiopia and other parts of the world for their delicious taste and portable nature [8, 26, 41].

Bonbolino

is a traditional Ethiopian dessert, also known as Ethiopian doughnuts. These delightful treats are typically made from a simple dough consisting of flour, yeast, sugar, and water. The dough is mixed until smooth and then allowed to rise before being shaped into small balls or rings. Once shaped, the dough is deep-fried until it becomes golden brown and crispy on the crust while remaining soft and fluffy on the crumb. Sometimes, after frying, Bonbolinos are often dusted with powdered sugar for added sweetness [26, 41].

Ambasha

is a well-known Ethiopian traditional flat bread. The fermented wheat dough is shaped into a round, flat disc and baked on a hot plate until it has a golden brown and cooked through. The texture of Ambasha is soft and fluffy on the crumb and crust. It is eaten either solely or together with other stews. Besides it can be eaten at any time of the day as a breakfast, lunch, or dinner. It is made up of wheat dough, salt, baking powder, yeast, oil, and small sugar [8, 26].

Results

Sociodemographic characteristics of the respondents

This study involved a total of 175 street food consumers from four Ethiopian towns: Addis Ababa, Dire Dawa, Hawassa, and Jimma. The majority of the respondents were males aged 20 to 29 years. The frequency of street food consumption among these consumers was categorized into three groups: daily or frequent (26.9%), weekly or average (52.6%), and monthly or occasional (20.5%), as shown in Table 2.

Table 2 Sociodemographic characteristics of the respondents, 2024, Ethiopia
Full size table

Prevalence of S. aureus

The mean prevalence of S. aureus in this study was 43.4% with the highest occurrence in Ambasha. The highest count was 4.88 × 105 CFU/g which was observed in Bonbolino. The mean prevalence of Salmonella species was 25.7% and the highest count was 4.2 × 102 CFU/g. The highest prevalence of Salmonella was observed in Bonbolino. As shown in Table 3.

Table 3 S. aureus and Salmonella loads of sampled ready-to-eat foods, 2024 Ethiopia
Full size table

Microbial risk assessment

The probability of infection from S. aureus was higher than that of Salmonella among street food consumers. Frequent and average consumers of Ambasha were at a slightly higher risk of infection for both S. aureus and Salmonella. The mean annual risk of S. aureus infection of consumers was 100%, 99.3%, and 93% for frequent, average, and occasional consumers respectively as it is shown in Table 4.

Table 4 S. aureus and Salmonella exposure assessment of the respondents, 2024 Ethiopia
Full size table

The mean annual risk of S. aureus infection was 100% for all three ready-to-eat food items. The mean annual risk of Salmonella infection was higher in frequent consumers of Ambasha than Bonbolino and Sambussa.

As shown in Tables  5, 32.6% of the sampled ready-to-eat foods were contaminated with S. aureus with a count greater than 104 CFU/g and were unfit for consumption whereas 25.7% were contaminated with Salmonella and unfit for consumption.

Table 5 S. aureus and Salmonella loads of the sample food, 2024 Ethiopia
Full size table

Discussion

Foodborne diseases remain a global challenge for public health and economic development, with cases rising worldwide [42]. The prevalence of S. aureus in the examined samples in this study was 43.4%. This prevalence was lower than reported in studies performed in different towns of Ethiopia and worldwide. 61% in the world [43], 53.9% [26] in Gondar, 64.4% [8] in Jigjiga, 53.7% [41]in Gondar. This finding was higher than those of studies conducted in Hawassa 9.9% [24], in Arbaminch 31, 9.4% [22], and in Gondar town 35.5% [23], in Iran, Theran 15.4% [37]. This variation could be due to differences in water activity (aw), pH values, and the type of sampled food, as S. aureus can grow under various conditions [42]. The use of low-quality, contaminated raw ingredients might also contribute to the high bacterial prevalence in ready-to-eat food [44]. Additionally, transmission might be from infected staff via respiratory passages, skin, and superficial wounds [37, 45] in preparation for smoky fires, and storing food at room temperature for 1–3 h before consumption could lead to contamination and pathogen proliferation [43].

The findings of this study also revealed that the prevalence of Salmonella species in the sampled ready-to-eat food items was 25.7%. This percentage was higher than that reported in studies conducted in Hawassa 12.7% [24], Jigjiga 19.7% [8], and Johannesburg 21.8% [46], whereas it was lower than that reported in studies conducted in Gondar 38% [41], and Bahirdar 57.5% [47]. This variation might be due to cross-contamination through the use of contaminated vegetables that are improperly cleaned, the type of sampled food items and environmental factors which might include exposure of the foods to air, the type of water used, the utensils used in the preparation and the personal hygiene of the vendors [45, 48].

The study revealed that the prevalence of S. aureus in Ambasha was higher than that in Bonbolino and Sambussa. This finding corroborates the findings of [49], who reported that Sambussa had a lower prevalence of S. aureus than Ambasha and Bonbolino. Whereas, a study in Gondar reported the highest incidence of S. aureus (66.7%) in Bonbolino [41], and a study in Jigjiga reported that the highest incidence (69%) in Sambussa [8]. The lower prevalence in Sambussa and Bonbolino observed in this study could be due to their preparation process, involving frying in boiled oil, and the presence of more oil on the surface of the food items may inhibit bacterial growth than Ambasha does [50]. The presence of S. aureus indicates contamination from the skin, mouth, or nose of food handlers through coughing and sneezing, often introduced during handling, processing, or vending [41, 51]. In addition, this might be due to the reuse of improperly washed dishes, open-air distribution, and improperly held temperatures during distribution. Moreover, street foods, which are frequently displayed and sold in unsanitary conditions by the roadside, can be easily contaminated by dust, insects, and consumers’ hands [52]. S. aureus is a commensal and opportunistic pathogen capable of causing numerous illnesses due to its toxin-mediated pathogenicity, invasiveness, and antimicrobial resistance [11].

Concerning Salmonella, the findings of this study revealed that more Salmonella species were isolated from Bonbolino than from Sambussa and Ambasha. This finding aligns with another in Gondar town, where the highest incidence of Salmonella (16.9%) was observed in Bonbolino [23], the differences between our results and those reported elsewhere could also be due to factors like sample source, and geographical origin [52].

The mean difference in S aureus and Salmonella among the three street food items was not statistically significant (p > 0.05) but significant differences were observed in individual food items among the four cities.

In this study, Quantitative Microbiological Risk Assessment (QMRA), which provides information on pathogen presence and growth to aid food safety decisions [15, 16]was used to estimate the risk of unsafe food on consumers. QMRA requires extensive data, and assumptions are made when data are unavailable [53] and uses deterministic and stochastic model [18]. For this study, a deterministic approach was used to estimate the risk. Variables were assigned fixed values, such as means or maximums, and the risk level was calculated using the consumption rate, pathogen dose, and food item weight, then categorized based on the results [54, 55].

In this study, 57 (32.6%) of the sampled ready-to-eat food items contained S.s aureus counts of > 104 and in 45 (25.7%) of the samples Salmonella was detected in which these counts were higher than the recommended reference value of the International Commission for Microbiological Specifications for ready-to-eat foods Center for Food Safety (2014). Microbial safety standards for ready to eat foods have been taken from international regulations, like the public health laboratory service guidelines for the microbiological quality of ready to eat foods [56], and the New South Wales (NSW) Food Authority microbiological quality guide for ready-to-eat foods [57]. This study result is similar to that of studies conducted in different developing countries [12, 45, 58].

The findings of this study revealed that consumers who frequently consumed street food were more likely to be infected by both S. aureus and Salmonella than those who consumed street foods on average or occasionally. Moreover, S aureus infection was more prevalent than Salmonella infection. This finding corroborates a study conducted by [10]. This might be due to the increase in the dose of the microorganisms. As the dose of the microorganism increases, the probability of infection increases [59]. The mean annual risk of frequent (daily) consumption by S aureus infection was similar for all three ready-to-eat food items at 100% of risk of infection. This result is similar to that of the study conducted by [49] where S aureus infection was similar for all three consumption frequencies that is daily, weekly, and monthly. The result of this study also revealed that the annual risk of Salmonella infection for frequent, average, or occasional consumers was approximately 92.6%, 38.7%, and 10.7%, respectively. S aureus and Salmonella are among the most common bacteria that cause food borne diseases. The presence of these organisms in ready-to-eat food depicts a deplorable state of poor hygiene and sanitary practices employed in the processing of this food product [60].

According to the public health laboratory service guidelines for the microbiological quality of ready-to-eat street foods and cited by [56], street foods are safe and fit for consumption, if the plate count is < 104 CFU/g. In this research, S.aureus load of some of the food samples was higher than the amount stipulated; hence, their presence above the stipulated amount constituted a health risk. Some of the street food retailed on the roads and streets of the selected towns in Ethiopia, as obtained in this study is not bacteriologically fit for consumption.

Conclusion

This study underscores the significant public health risks posed by foodborne pathogens, particularly S aureus and Salmonella, in ready-to-eat street foods. The prevalence of these pathogens varies widely across different locations and food types and is, influenced by factors such as food handling practices, environmental conditions, and hygiene standards. The high levels of contamination found in some samples exceeded international street food safety guidelines, indicating poor sanitary practices and potential health risks for consumers. The deterministic quantitative microbiological risk assessment highlighted that frequent consumers of street foods face a high risk of infection, with S aureus being more prevalent than Salmonella. Overall, these findings call for improved hygiene practices and stricter regulatory measures to ensure the microbiological safety of street foods in Ethiopia. In addition, the respective towns’ health and regulatory offices should implement strict monitoring strategies to minimize the risk of contamination of street foods. Moreover, policymakers, public health authorities, and food vendors can work collaboratively to mitigate the risks associated with foodborne pathogens in street food, enhancing public health and consumer confidence.

Limitations

The use of the deterministic quantitative microbial risk assessment approach to estimate the risk of infection from microbial contaminants in street food in this study relies on fixed values and does not account for variability or randomness in factors such as pathogen concentration and environmental conditions. It assumes specific conditions and inputs, such as the mean pathogen levels, average consumption rates, and typical food handling practices, to calculate the risk of infection. This method provides straightforward risk estimates that are easy to interpret but may overlook the inherent variability in real-world scenarios. Moreover, S. aureus bacteria isolated in this study were not further characterized for presence of enterotoxins thus it is possible that the risk of staphylococcal food poisoning may be overestimated.

Data availability

Data is provided within the manuscript.

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Acknowledgements

The authors would like to acknowledge, Jimma University, NORPART EXCELL SMART Project, UiO, Oslo Norway and CIH LMU One Health Center for International Health, University Hospital, LMU Munich, Germany for giving scholarship to write the article in Oslo, Norway, and University of Oslo, College of health and society. Moreover Oslo metropolitan University Oslo, Norway to let me to have an office while I am writing this article, Addis Ababa, Dire Dawa, Hawassa and Jimma towns administration offices for facilitating data collection process, Haramaya, Hawassa, and Jimma University laboratory departments and Ethiopian public health institute food and nutrition department microbiology laboratory unit for letting me to conduct laboratory analysis. Professor Jeanette H. Magnus, and Professor Dawit Shawel giving direction and technical advice, Mrs. Ester Mæland for supporting and guiding me in all aspects while I was in Oslo, Data collectors and all street food vendors who were participated in our study. People who are directly or indirectly encouraged us while doing this study.

Funding

Jimma University covered the cost of data collectors.

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Authors and Affiliations

  1. College of medicine and health sciences, Department of Environmental Health, Hawassa University, Hawassa, Ethiopia

    Mathewos Moges

  2. Division of Water and Health, Ethiopian Institute of Water Resources, Addis Ababa University, Addis Ababa, Ethiopia

    Argaw Ambelu

  3. Norwegian Institute of Public Health, Oslo, Norway

    Ernst Kristian Rodland

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  1. Mathewos Moges
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Contributions

MM: conceptualization, methodology, validation, formal analysis, investigation, data curation, writing original draft preparation. AA: conceptualization, methodology validation writing, review and editing, and supervision. EKR: Designed the study, reviewed the draft manuscript, and edited the manuscript. All authors reviewed the manuscripts and agreed to the published version.

Corresponding author

Correspondence to Mathewos Moges.

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Ethics approval and consent to participate

This study was conducted in agreement with the Declaration of Helsinki, the Ethical principle for medical research involving human subjects. Jimma University’s institutional review board has provided ethical clearance (JUIH/IRB/201/22) and Informed consent was obtained from all subjects involved in the study.

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It is not applicable.

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The authors declare no competing interests.

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Moges, M., Rodland, E.K. & Ambelu, A. Health risk assessment of Staphylococcus aureus and Salmonella from the consumption of street foods in Ethiopia. BMC Infect Dis 25, 576 (2025). https://doiorg.publicaciones.saludcastillayleon.es/10.1186/s12879-025-10977-5

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BMC Infectious Diseases

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