Incidence Of Foodborne Diseases Research Articles

Assessment of the Antibacterial Potency of Usnea sp. against Foodborne Pathogens

ABSTRACT 
 The increase in the incidence of foodborne diseases has been demonstrated by epidemiological studies, and the adverse impact on the socio-economic development of countries has been also reported by health authorities. The combat against foodborne pathogens through the use of natural biosources has become the focus of recent research. Lichens produce several secondary metabolites with various biological activities including antibacterial, antifungal, anti-cancer etc. due to competition with other living things in their surrounding environment. In this perspective, we aimed to investigate the antibacterial properties of Usnea sp. that collected from Kastamonu, Turkey against five foodborne pathogens in the present study. These tested bacteria included both Gram-positive and Gram-negative ones. Our data demonstrated that the acetone extracts of Usnea sp. had antibacterial efficiencies especially against Gram-positive bacteria tested (C. perfringens, S. aureus, and B. cereus) at varying percentages. This potential antibacterial activity of Usnea sp. suggests that it can be used in the food industry. Since it has already been reported to be used in dishes or ingredients of bread, it gives the idea that it may be used as a food additive (such as a preservative, extending shelf life). However, detailed studies for its toxicity or the dosages that do not be toxic should be done.

Effects of Climatic Factors on Diarrheal Diseases among Children below 5 Years of Age at National and Subnational Levels in Nepal: An Ecological Study.

Introduction: The incidence of diarrhea, a leading cause of morbidity and mortality in low-income countries such as Nepal, is temperature-sensitive, suggesting it could be associated with climate change. With climate change fueled increases in the mean and variability of temperature and precipitation, the incidence of water and food-borne diseases are increasing, particularly in sub-Saharan Africa and South Asia. This national-level ecological study was undertaken to provide evidence linking weather and climate with diarrhea incidence in Nepal. Method: We analyzed monthly diarrheal disease count and meteorological data from all districts, spanning 15 eco-development regions of Nepal. Meteorological data and monthly data on diarrheal disease were sourced, respectively, from the Department of Hydrology and Meteorology and Health Management Information System (HMIS) of the Government of Nepal for the period from 2002 to 2014. Time-series log-linear regression models assessed the relationship between maximum temperature, minimum temperature, rainfall, relative humidity, and diarrhea burden. Predictors with p-values < 0.25 were retained in the fitted models. Results: Overall, diarrheal disease incidence in Nepal significantly increased with 1 °C increase in mean temperature (4.4%; 95% CI: 3.95, 4.85) and 1 cm increase in rainfall (0.28%; 95% CI: 0.15, 0.41). Seasonal variation of diarrheal incidence was prominent at the national level (11.63% rise in diarrheal cases in summer (95% CI: 4.17, 19.61) and 14.5% decrease in spring (95% CI: −18.81, −10.02) compared to winter season). Moreover, the effects of temperature and rainfall were highest in the mountain region compared to other ecological regions of Nepal. Conclusion: Our study provides empirical evidence linking weather factors and diarrheal disease burden in Nepal. This evidence suggests that additional climate change could increase diarrheal disease incidence across the nation. Mountainous regions are more sensitive to climate variability and consequently the burden of diarrheal diseases. These findings can be utilized to allocate necessary resources and envision a weather-based early warning system for the prevention and control of diarrheal diseases in Nepal.

Research on nanogold-assisted HRM-qPCR technology for highly sensitive and accurate detection of Vibrio parahaemolyticus

The incidence of foodborne diseases ranks at the forefront of the total incidence of various diseases. High-specificity and high-sensitivity detection and reporting of foodborne pathogens have become the core of preventing and solving food safety problems. This study is based on screened highly specific molecular targets, the addition of the third-generation saturated fluorescent dyes and nanogold reduces the Ct value of the system while increasing the fluorescence signal value, thereby establishing highly sensitive and specific Nanogold-assisted HRM-qPCR rapid detection technology. The limit of detection and quantification of assay was 7 fg/μL-70 ng/μL for genomic DNA and 6 CFU/mL-6 × 106 CFU/mL for bacterial suspension. The Nanogold-assisted HRM-qPCR was shown to be able to detect Vibrio parahaemolyticus of 30 CFU/mL without enrichment culture and 3 CFU/mL after 2 h enrichment culture. This work shows promise in rapid instrumental and on-site detection of Vibrio parahaemolyticus.

The Critical Role of Consumers in the Prevention of Foodborne Diseases: An Ethnographic Study of Italian Families.

A high incidence of foodborne diseases occurs in the home setting because consumers adopt inappropriate preparation, consumption, and storage procedures. The present study applies an ethnographic approach to identify inadequate practices that could increase the incidence of foodborne diseases. Techniques related to the ethnographic approach were used: participant observation, kitchens mapping, collection of photographic material, and informal interviews in natural settings. A sample of 14 families was involved through the snowball sampling technique. This study identifies habitual practices and routine behaviour as the main risk factors. The inadequacies most frequently encountered related to the microbiological risks are incorrect handwashing, the presence in the kitchen spaces of objects unrelated to food preparation, the improper use of dishcloths and sponges, the inappropriate washing of utensils and food, the incorrect storage of food in the fridge, and the presence of children and pets without an adequate administration of the spaces. The practices that can expose consumers to chemical risk include food preservation through unsuitable containers/materials, food overcooking, and detergents contamination. The data underline the need to implement communicative and training interventions that give precise and targeted indications about correct safety practices in the home setting.

Knowledge, attitude, and practice regarding food hygiene among food handlers of eating establishments of a medical college, Pune, Maharashtra: A cross-sectional study

Background: Food handler is any person who handles food, regardless whether he/she actually prepares or serves it. The chances of food getting contaminated depend on their knowledge of food hygiene and its application. Any incidence of food-borne diseases that affect medical students and doctors can result not only in sickness absenteeism but also in case of transmission of pathogen to patients and their relatives which ultimately affect the health care services to a great extent. Therefore, the present study was conducted to assess knowledge, attitude, and practice (KAP) of food hygiene and safety among food handlers of eating establishments of medical college and attached hospital. Materials and Methods: A present, cross-sectional study conducted among all the food handlers of food establishments in the premises of Medical College and attached General Hospital in Pune in June–July 2017 selected by the universal sampling method. They were interviewed with prestructured questionnaire. The data were entered in MS excel and analyzed using Epi Info version 7.2. Results: A total 105 food handlers, mean age of 29.4 ± 11.02 years were enrolled. Maximum study participants 71 (67.6%) had good knowledge, 74 (70.5%) had favorable attitude, and 82 (78.1%) had good practice. There was positive relationship between both knowledge and attitude, knowledge and practice, also attitude and practice. It can be anticipated that as knowledge will increase, attitude, and practice will improve accordingly. Conclusion: Education, training, and the development of food safety certification examinations are the key components in the process of ensuring that food handlers are proficient in and knowledgeable about food safety and sanitation principles.

Global impact of foodborne diseases on health

The occurrence of foodborne diseases (FBD) has increased in the last decade as a result of negligence for hygiene. Prevalence of FBD due to lack of education, insufficient health services result in the spread of disease on a larger scale. Personal hygiene, as well as local cleanliness, is the most important aspect of the overall health community. Pandemic like COVID is due to lack of personal hygiene as well as health education. The data published by global bodies like World Health Organization (WHO) indicates that the FBD should be controlled by increasing awareness related to personal hygiene and health education. This article reviewed the global occurrence of FBD, preventive measures and solutions for an overall healthy community. The aim of this review is to analyse reports related to foodborne diseases over the globe and suggest guidelines for community health. The scope of this review is in food safety and quality – microbiological and chemical in Food research Journal. Reviews, reports, research data related to foodborne diseases have been analysed and future solutions for building a better health community have been suggested. A total of 74 references including research articles, reviews, press notes, government sites related to foodborne diseases over the globe have been reviewed and data collection has been analysed to suggest better health community guidelines. All the references showed that the occurrence of foodborne diseases are increasing day by day and thus control measure policies have to be implemented worldwide. These include strict government policies, education of food vendors, strict action against those who are not following it, educating the importance of personal as well as community hygiene. These results will surely help to build a better healthy community in future. The data showed that foodborne disease is affecting many populations at any age each year leading to morbidity and mortality. The disease is caused by bacteria, viruses, parasites and fungi. The common symptoms are diarrhoea, vomiting, fever and abdominal pain. Awareness and education related to community health should be spread using advertisements, social media, newspapers, news channels to lower the incidence of foodborne diseases.

Surveillance results of foodborne diseases in Huzhou, Zhejiang, 2018–2020

Objective To discuss the infection status and epidemiological characteristics of foodborne diseases in Huzhou of Zhejiang province. Methods The Salmonella, Vibrio parahaemolyticus, diarrheogenic Escherichia coli strains from 6 sentinel hospitals (3 key surveillance points and 3 routine surveillance points) in Huzhou from 2018 to 2020 were used for serotyping and virulence gene detection;Real-time PCR was conducted for the nucleic acid detection of norovirus. Results A total of 6783 samples of diarrhea cases were detected, and 1373 were pathogen positive, with a detection rate of 20.24%. The detection rate of diarrheogenic E. coli was 6.49%, mainly enteroaggregative E. coli and enterotoxigenic E. coli. The detection rate of V. parahaemolyticus was 5.31%, the main serotype was O3∶K6, and the main virulence genotype was tdh. The detection rate of Salmonella was 2.85%, with S. typhimurium as the main species. The positive rate of norovirus was 11.65%, and the genotype was mainly GⅡ.2［P16］. The incidence peak of pathogenic bacteria infection was in summer, and the incidence peak of norovirus infection was in winter and spring, and people aged 20–39 years were mostly affected. Conclusion The pathogens causing infectious diarrhea in Huzhou from 2018 to 2020 were norovirus, diarrheogenic E. coli, V. parahaemolyticus and Salmonella, and the infection incidence showed obvious seasonal and age distributions. The surveillance for foodborne pathogens should be strengthened to effectively prevent and control the incidence of foodborne diseases.

Product quality of kaledo, a local food of Palu City Indonesia

Food safety is an important issue in the incidence of foodborne diseases in society. Kaledo is one of the “must-try” traditional foods of Palu City, Indonesia. The main ingredients used for making this dish are beef and cow’s trotters, which are highly susceptible to microbiological, physical, and chemical contamination. This cross-sectional study aimed to analyze the Good Manufacturing Practice (GMP) and Hazard Analysis Critical Control Point (HACCP) in one of the culinary businesses in Palu City. The GMP assessment was carried out using the self-assessment questionnaire developed by Food Supplements Europe. The results of this study indicated that Kaledo X Food Stall still had not implemented GMP. However, HACCP analysis showed a critical control point (CCP) in the cooking process of Kaledo, i.e., at the time of boiling the meat and bones.

A Qualitative Assessment of the Risks of Transmission of Microorganisms to Humans Resulting from the Consumption of Raw Milk and Raw Cream in Norway

Pasteurisation of all consumer milk became mandatory in Norway in 1953, and this has been an important component of the protective measures that have reduced the incidence of milk and food borne diseases. In 2004, a complete recast of the hygiene legislation addressing both food hygiene and veterinary aspects was adopted by the European Union, the so-called “Hygiene package”. According to this legislation, each member state may, on its own initiative, prohibit or restrict the marketing of some foods like raw milk or raw cream, intended for direct human consumption within its territory. In response to this, the Norwegian Food Safety Authority (Mattilsynet) commissioned the Panel on Biological Hazards of the Norwegian Scientific Committee for Food Safety (Vitenskapskomitéen for mattrygghet), to prepare a risk assessment regarding the consumption of raw milk and raw cream. In response, an ad hoc Working Group of experts was appointed with the mandate to draft a risk assessment which should include the following components: identification and characterization of microbiological hazardous agents present in Norwegian raw milk; characterization of the public health consequences of these agents; assessment of the probability of transmission of these agents to humans by distribution of raw milk and cream. Additionally, the risk assessment should identify potential hazards to human health from the importation of raw milk, identify hazards associated with equipment used for production and storage of raw milk, and assess the risks associated with the potential transfer of antimicrobial resistance genes.&#x0D; &#x0D; Observations concerning infections related to consumption of raw milk and raw cream in Norway, other European countries and North America, show that a number of pathogenic microorganisms, including emerging pathogens, can occur in raw milk and raw cream. These pathogenic microorganisms and their toxins may represent a real threat to human health. The panel concluded that the risks associated with E. coli O157:H7 and other EHEC, C. jejuni and L. monocytogenes in raw milk and cream are high. Furthermore the importation of raw milk to Norway may result in the (re)introduction of microorganisms, which have been eradicated, or never previously have been present, in Norway. This can have serious consequences for both human and animal health.

Fe-MIL-88NH2 Metal–Organic Framework Nanocubes Decorated with Pt Nanoparticles for the Detection of Salmonella

Early screening of Salmonella is of utmost importance to minimize the incidence of related foodborne diseases. Here, we reported an immunosensor to fast detect Salmonella using Fe-MIL-88NH2 metal–o...

Interrelationship between climatic factors and incidence of FBD caused by Clostridioides difficile toxin B, Clostridium perfringens, Campylobacter spp., and Escherichia coli O157:H7.

Foodborne diseases (FBDs) remain a global public health concern. Climatic factors such as wind-chill temperature, rainfall, and relative humidity affect the incidence of several FBDs. This study was performed to analyze how the various factors of the climate influence the incidence and severity of FBDs. This study retrospectively analyzed the results of multiplex polymerase chain reaction (mPCR) tests for diarrhea-causing bacteria performed on 2300 fecal samples obtained from patients at Dankook University Hospital, Cheonan, from June 2010 to December 2019. The Clostridioides difficile toxin B infection rate positively correlated with the intensity of sunshine, and the content of particulate matter. The Campylobacter spp. infection rate positively correlated with wind-chill temperature and the content of particulate matter. The Escherichia coli O157:H7 infection rate positively correlated with relative humidity. These findings may explain the dynamics and risks of Clostridioides difficile toxin B, Clostridium perfringens, Campylobacter spp., and Escherichia coli O157:H7 infection. They may help predict interrelationships among climatic factors and standardize national environmental health policies. However, in-depth research with large-scale data, molecular biology, and epidemiology would be required going forward. Future research would also require objective indicators of the changes in the prevalence of FBD-causing microbial pathogens for the effective prevention and management of these bacterial infections.

Surveillance of foodborne diseases in Taiwan: A retrospective study.

Foodborne pathogens cause diseases and death, increasing the economic burden. It needs to identify incident places, media food and pathgens. Our aim is to survey empirical data that provide a retrospective historical perspective on foodborne diseases and explore the causes and trends of outbreaks.We examined publicly available annual summary data on reported foodborne disease outbreaks in Taiwan from 2014 to 2018. We calculated the percentage of places, media food, bacteria and natural toxin sources in foodborne diseases and performed a chi-square test for difference evaluation. The higher risk of places and causes in 2018 compared with 2014 was empolyzed with univariate logistic regression.There were 26847 patients with foodborne diseases during the period from 2014 to 2018. The top 2 primary source locations of the foodborne diseases were schools and restaurants. The top 2 primary food media classifications of the foodborne diseases were boxed meals and compounded foods. The top 2 primary incident bacterial classifications of the observed foodborne diseases were Bacillus cereus and Staphylococcus aureus. The top 2 primary natural toxin classifications of the foodborne diseases were plants and histamines. The incidence of foodborne disease in military facilities, fruits and vegetables, and Staphylococcus aureus was increased in our study.Our study confirmed the high risk and increased incidence of foodborne diseases, food media classifications, bacterial classifications, and natural toxins in Taiwan. It is worthy of attention for the government health department-designed policy to promote disease prevention.

Microbial structure and function diversity of open dumpsite compost used as fertilizer by peasant farmers

A study was carried out to assess the microbial communities and functions in addition to several key environmental variables (pH, temperature, carbon, nitrogen, carbon to nitrogen ratio, and moisture) of open dumpsite compost. Sampling was done on days 45 and 90 following composting of the organic fraction of the municipal solid waste (MSW). Following community DNA extraction, sequencing was done on Illumina Miseq platform. Pair-ends of the sequences reads were assembled using the make-contigs tool while open reading frame (ORFs) was done using FragGeneScan and these were functionally annotated to several bioinformatics pipelines. Structural composition revealed 5 kingdoms namely bacteria, protozoa, unknown, archaea, and fungi but with varying degree of abundance. After unknown phyla, proteobacteria was the second dominant phyla with abundance of 42.45 and 40.30% , respectively on days 45 and 90 and they were well represented in the class, order and family taxas in both samples. Majority of the genus in both samples were uncultured genus. However, potential pathogenic species belonging to the genuses Clostridium, Escherichia, Pseudomonas, Enterococcus, Micrococcus, Shigella, Klebsiella and Bacillus amongst other were detected in our samples on 90days. Physiological diversity assessment revealed that carbohydrate (CHO) metabolisms were the most dominant and was almost similar in both samples. At day 45, the CHO metabolisms were dominated by phylotypes belonging to the alphaproteobacteria and betaproteobacteria classes of bacteria but it was more diverse on day 90 as Chlorobi, Gammaproteobacteria, Firmicutes, Actinobacteria, Tenericutes, and Planctomycetes were also involved. Other metabolisms such as amino acid, nucleotides, vitamins and co-factors, xenobiotics, genetic information and well as environmental information processing were also captured. This practice should be discouraged to avoid incidence of food-borne diseases.

Review of recent advances in improved lateral flow immunoassay for the detection of pathogenic Escherichia coli O157:H7 in foods

AbstractThe incidence of foodborne diseases has continuingly increased over the years and resulted in public health problem globally. EnterohemorrhagicEscherichia coliO157:H7 (E. coliO157:H7) is a human pathogen that causes diarrhea and hemorrhagic colitis.E. coliO157:H7 can be found in various foods. It is important to detect this foodborne pathogen to provide safe food supply. A lot of methods, for example, culture and PCR‐based test, used to detect foodborne pathogens are laborious and time consuming. Hence, a variety of methods have been developed for rapid, simple and reliable detection ofE. coliO157:H7 as it is required in many food analyses. Lateral flow immunoassay (LFIA) are advantageous over conventional detection methods in terms of their rapidity and simplicity for end user, especially the LFIA can be developed as the strip test for on‐site point‐of‐care test (POCT) products. Gold nanoparticles (AuNPs; colloid gold) are the most commonly used labels in the LFIA for the visual analysis, however, there are still several limitations that restrict their applications of traditional LFIA. Therefore, recent reports on improved LFIA forE. coliO157:H7 detection in foods are continuously reported. This review intends to provide these recent advances in improved LFIA methods for the detection ofE. coliO157:H7 in foods.

Transmission Media of Foodborne Diseases as an Index Prediction of Diarrheagenic Escherichia coli: Study at Elementary School, Surabaya, Indonesia.

Foodborne diseases (FBDs) have a large disease burden among children. The major type of FBD in children is diarrhea, caused mainly by contaminated food. One of the diarrhea pathogens is Diarrheagenic Escherichia coli (DEC). The aim of this study was to establish a model of microbial prediction (DEC) in stool, caused by the transmission of FBDs in elementary schoolchildren. An observational analytic study was conducted, with a nested case-control study design. In Stage I, the study population was children in a selected elementary school at Surabaya. The sample size for Stage I was 218 children. In Stage II, the case sample was all children with a positive test for DEC (15 children), and the control sample was all children who had tested negative for DEC (60 children). The result of the laboratory tests showed that the proportion of DEC in children was 6.88% (15 of 218 children) and the proportion of Escherichia coli O157:H7 in children was only 0.46%. The most significant mode of transmission included in the model was the snacking frequency at school and the risk classification of food that was often purchased at school. The formulation of the predicting model of DEC in stool can be used as an early warning against the incidence of FBDs in elementary schoolchildren.

Salmonella Infection Among Food Handlers at Canteens in a Campus

Background: Salmonella is one of the pathogenic microorganisms that can contaminate food through cross-contamination (less hygiene of handlers and environment). In a campus, food management and food handlers have a very important role in the contamination of microorganisms, which can lead to the incidence of foodborne diseases. Objective: This study aimed to assess the incidence of salmonella infections among food handlers at a campus canteen in Depok City, Indonesia. Methods: The cross-sectional study was conducted in May-June 2017. The population of this study was all food handlers working in the canteen (N=260). The data were obtained through interviews and observation of the characteristics and behaviors of the food handlers. Blood samples were also collected from 49 food handlers (n=49). Results: This study revealed that 61.2% of food handlers included in the age group were not at risk, the proportion of female food-handlers was slightly more than men (51%), the majority of them were low educated (59.2%), and all respondents had never given typhoid immunization. The results of the fecal examination revealed that two food handlers had typhoid. In addition, the behavior and personal hygiene of most of the handlers are poor. Environmental factors such as canteen sanitation facilities are mostly qualified, and most of the food handlers have no history of contact with animals. Conclusion: There was no statistically significant relationship between characteristics, behavior, personal hygiene, sanitation facilities, and contact history with animals against pathogenic bacterial infections.

Self-Organizing System of Budgetary Allocation for Food Borne Diseases in the Philippines

The food system is one of the complex systems that require a theoretic perspective. The core objective of the study was to identify an emergent feature described by the variables: total foodborne diseases, and health care expenditure in the 16 regions of the Philippines. This study employed the descriptive-analytic research, utilized data mining, factor analysis, cluster analysis, and complex adaptive systems. Factor analysis results revealed that the factor or feature outlines a foodborne disease allocation. Two clusters were generated using cluster analysis. The first cluster comprised regions with foodborne diseases ranging from 212-890 incidences, and the second cluster contained regions with 1338 to 4770 foodborne disease cases. National Capital Region (NCR), MIMAROPA, Regions 1, 2, 3, 5, 8, and 11 belonged to the cluster with lower incidences of foodborne diseases. These regions also had high positive synergy. Results also revealed that Regions 4, 6, 7, 9, 10, 12, CAR, and CARAGA had higher foodborne disease cases which correspondingly showed extensive distinctions among regions. The emerging pattern appeared to be random albeit cyclical in nature with no upward nor downward drift. This demonstrated an amplitude and slight upward drift as well. To sum, it was detected that there are two emergent patterns in budgetary allocation for foodborne diseases in the Philippines: those regions for which budgetary allocation for foodborne diseases were not based on actual incidences of the diseases, and those regions for which budgetary allocation were more sensitive to the incidence of foodborne diseases.

Natural Preservatives from Plant in Cheese Making.

Simple SummaryCheese is a food that is susceptible to contamination by pathogenic and spoilage microorganisms, which can result in a reduced cheese shelf life, as well as in risks to the consumers’ health. This implies the possible use of preservatives in the cheese making process. At the same time, consumers are increasingly demanding for healthy food, free from synthetic preservatives. Just for this reason, natural ingredients are receiving increasing attention as substitutes for synthetic additives, also because they have bioactive compounds, which might provide health benefits in the prevention of several diseases. Furthermore, most of natural ingredients have shown antimicrobial activity, which could delay or inhibit the growth of pathogenic microorganisms in food, as well as minimize the incidence of foodborne diseases caused by food spoilage bacteria and fungi. This review aims at discussing the antimicrobial activity of the main natural ingredients derived from plants and used in cheese making, and their effect on cheese quality, in terms of chemical, nutritional and sensory characteristics of the products, as well as the increase in cheese shelf-life.Today, consumers are increasingly demanding safety alternatives concerning the use of synthetic additives in the food industry, as well as healthy food. As a result, a major number of plant-derived preservatives have been tested in the food industry. These natural ingredients have antioxidant properties and have shown to increase the bioactive molecules levels and the microbiological stability of the food items. The effect of the plant-based preservatives on the sensorial properties of the new products has also to be considered, because natural preservatives could result in sensorial characteristics that may not be accepted by the consumers. Cheese is a dairy product widely appreciated all over the world, but it is also susceptible to contamination by pathogenic and spoilage microorganisms; therefore, the use of preservatives in cheese making represents an important step. This review deals with one of the innovation in the cheese sector, which is the addition of natural preservatives. Several aspects are discussed, such as the effect of natural ingredients on the microbial stability of cheese, and their influence on the chemical, nutritional and sensorial characteristics of the cheeses. Although the promising results, further studies are needed to confirm the use of natural preservatives from plants in cheese making.

Research progress of biosensors in the detection of foodborne pathogens

As the main factor leading to foodborne illnesses, foodborne pathogens have been attached great importance by people. The development of simple, rapid, high-sensitivity and low-cost food-borne pathogen detection methods is of great significance in reducing the incidence of foodborne diseases. Biosensor technology is a new micro-analysis technology developed by multi-disciplinary cross-infiltration. It has the characteristics of high sensitivity and fast analysis speed, and is widely used in the detection of food-borne pathogens. This paper introduces the basic principles of biosensors, summarizes the application of common biosensors in the detection of foodborne pathogens, and prospects for future development.

Simultaneous Colorimetric Detection of a Variety of Salmonella spp. in Food and Environmental Samples by Optical Biosensing Using Oligonucleotide-Gold Nanoparticles

Optical biosensors for rapid detection of significant foodborne pathogens are steadily gaining popularity due to its simplicity and sensitivity. While nanomaterials such as gold nanoparticles (AuNPs) are commonly used as signal amplifiers for optical biosensors, AuNPs can also be utilized as a robust biosensing platform. Many reported optical biosensors were designed for individual pathogen detection in a single assay and have high detection limit (DL). Salmonella spp. is one of the major causative agents of foodborne sickness, hospitalization and deaths. Unfortunately, there are around 2,000 serotypes of Salmonella worldwide, and rapid and simultaneous detection of multiple strains in a single assay is lacking. In this study, a comprehensive and highly sensitive simultaneous colorimetric detection of nineteen (19) environmental and outbreak Salmonella spp. strains was achieved by a novel optical biosensing platform using oligonucleotide-functionalized AuNPs. A pair of newly designed single stranded oligonucleotides (30-mer) was displayed onto the surface of AuNPs (13 nm) as detection probes to hybridize with a conserved genomic region (192-bases) of ttrRSBCA found on a broad range of Salmonella spp. strains. The sandwich hybridization (30 min, 55°C) resulted in a structural formation of highly stable oligonucleotide/AuNPs-DNA complexes which remained undisturbed even after subjecting to an increased salt concentration (2 M, final), thus allowing a direct discrimination via color change of target (red color) from non-target (purplish-blue color) reaction mixtures by direct observation using the naked eye. In food matrices (blueberries and chicken meat), nineteen different Salmonella spp. strains were concentrated using immunomagnetic separation and then simultaneously detected in a 96-well microplate by oligonucleotide-functionalized AuNPs after DNA preparation. Successful oligonucleotide/AuNPs-DNA hybridization was confirmed by gel electrophoresis while AuNPs aggregation in non-target and control reaction mixtures was verified by both spectrophotometric analysis and TEM images. Results showed that the optical AuNP biosensing platform can simultaneously screen nineteen (19) viable Salmonella spp. strains tested with 100% specificity and a superior detection limit of <10 CFU/mL or g for both pure culture and complex matrices setups. The highly sensitive colorimetric detection system can significantly improve the screening and detection of viable Salmonella spp. strains present in complex food and environmental matrices, therefore reducing the risks of contamination and incidence of foodborne diseases.