RESUMEN
One of the main challenges in food microbiology is to prevent the risk of outbreaks by avoiding the distribution of food contaminated by bacteria. This requires constant monitoring of the circulating strains throughout the food production chain. Bacterial genomes contain signatures of natural evolution and adaptive markers that can be exploited to better understand the behavior of pathogen in the food industry. The monitoring of foodborne strains can therefore be facilitated by the use of these genomic markers capable of rapidly providing essential information on isolated strains, such as the source of contamination, risk of illness, potential for biofilm formation, and tolerance or resistance to biocides. The increasing availability of large genome datasets is enhancing the understanding of the genetic basis of complex traits such as host adaptation, virulence, and persistence. Genome-wide association studies have shown very promising results in the discovery of genomic markers that can be integrated into rapid detection tools. In addition, machine learning has successfully predicted phenotypes and classified important traits. Genome-wide association and machine learning tools have therefore the potential to support decision-making circuits intending at reducing the burden of foodborne diseases. The aim of this chapter review is to provide knowledge on the use of these two methods in food microbiology and to recommend their use in the field.
Asunto(s)
Bacterias , Microbiología de Alimentos , Enfermedades Transmitidas por los Alimentos , Estudio de Asociación del Genoma Completo , Aprendizaje Automático , Humanos , Bacterias/genética , Enfermedades Transmitidas por los Alimentos/microbiología , Enfermedades Transmitidas por los Alimentos/genética , Variación Genética , Genoma Bacteriano , Estudio de Asociación del Genoma Completo/métodos , FenotipoRESUMEN
The use of direct nucleic acid amplification of pathogens from food matrices has the potential to reduce time to results over DNA extraction-based approaches as well as traditional culture-based approaches. Here we describe protocols for assay design and experiments for direct amplification of foodborne pathogens in food sample matrices using loop-mediated isothermal amplification (LAMP) and polymerase chain reaction (PCR). The examples provided include the detection of Escherichia coli in milk samples and Salmonella in pork meat samples. This protocol includes relevant reagents and methods including obtaining target sequences, assay design, sample processing, and amplification. These methods, though used for specific example matrices, could be applied to many other foodborne pathogens and sample types.
Asunto(s)
ADN Bacteriano , Microbiología de Alimentos , Leche , Técnicas de Amplificación de Ácido Nucleico , Reacción en Cadena de la Polimerasa , Salmonella , Técnicas de Amplificación de Ácido Nucleico/métodos , Microbiología de Alimentos/métodos , Animales , Leche/microbiología , Salmonella/genética , Salmonella/aislamiento & purificación , ADN Bacteriano/genética , ADN Bacteriano/aislamiento & purificación , Reacción en Cadena de la Polimerasa/métodos , Enfermedades Transmitidas por los Alimentos/microbiología , Escherichia coli/genética , Escherichia coli/aislamiento & purificación , Técnicas de Diagnóstico Molecular/métodos , PorcinosRESUMEN
Foodborne pathogens continue to be a major health concern worldwide. Culture-dependent methodologies are still considered the gold standard to perform pathogen detection and quantification. These methods present several drawbacks, such as being time-consuming and labor intensive. The implementation of real-time PCR has allowed to overcome these limitations, and even reduce the cost associated with the analyses, due to the possibility of simultaneously and accurately detecting several pathogens in one single assay, with results comparable to those obtained by classical approaches. In this chapter, a protocol for the simultaneous detection of two of the most important foodborne pathogens, Salmonella spp. and Listeria monocytogenes, is described.
Asunto(s)
Microbiología de Alimentos , Enfermedades Transmitidas por los Alimentos , Listeria monocytogenes , Reacción en Cadena de la Polimerasa Multiplex , Salmonella , Listeria monocytogenes/genética , Listeria monocytogenes/aislamiento & purificación , Microbiología de Alimentos/métodos , Salmonella/genética , Salmonella/aislamiento & purificación , Reacción en Cadena de la Polimerasa Multiplex/métodos , Enfermedades Transmitidas por los Alimentos/microbiología , Enfermedades Transmitidas por los Alimentos/diagnóstico , Reacción en Cadena en Tiempo Real de la Polimerasa/métodos , Humanos , ADN Bacteriano/genética , ADN Bacteriano/análisisRESUMEN
In food industry, Listeria monocytogenes contamination can occur accidentally despite the quality control of raw materials and factory. Decontamination processes or inhibitory effects of ingredients/additives in food products are set up to ensure compliance with hygiene and microbiological criteria. These actions represent stresses for the pathogenic agent, causing fluctuations in its physiological states. Moreover, during these environmental stresses, Listeria monocytogenes can enter in a viable but nonculturable (VBNC) state which is not detected by plate counting but by flow cytometry. This technique coupled with cell staining by fluorescent dyes offers the possibility to assess different physiological states based on different cellular parameters: enzymatic activity, transmembrane integrity, membrane potential, and respiratory activity. In this chapter, we present a method to assess the viability of foodborne pathogens using a double-staining principle based on the assessment of membrane integrity and intracellular esterase activity.
Asunto(s)
Citometría de Flujo , Listeria monocytogenes , Viabilidad Microbiana , Listeria monocytogenes/crecimiento & desarrollo , Listeria monocytogenes/fisiología , Citometría de Flujo/métodos , Microbiología de Alimentos/métodos , Colorantes Fluorescentes/química , Coloración y Etiquetado/métodos , Membrana Celular/metabolismoRESUMEN
Foodborne pathogens are responsible for foodborne diseases and food poisoning and thus pose a great threat to food safety. These microorganisms can adhere to surface and form a biofilm composed of an extracellular matrix. This matrix protects bacterial cells from industrial environmental stress factors such as cleaning and disinfection operations. Moreover, during these environmental stresses, many bacterial species can be entered in a viable but nonculturable (VBNC) state. VBNC cells are characterized by an active metabolism and a loss of cultivability on conventional bacteriological agar. This leads to an underestimation of total viable cells in environmental samples and thus may pose a risk for public health. In this chapter, we present a method to detect viable population of foodborne pathogens in industrial environmental samples using a molecular method combining propidium monoazide (PMA) and quantitative PCR (qPCR) and a fluorescence microscopic method associated with the LIVE/DEAD BacLight™ viability stain.
Asunto(s)
Azidas , Microbiología de Alimentos , Viabilidad Microbiana , Propidio , Reacción en Cadena en Tiempo Real de la Polimerasa , Microbiología de Alimentos/métodos , Azidas/química , Propidio/análogos & derivados , Reacción en Cadena en Tiempo Real de la Polimerasa/métodos , Bacterias/genética , Bacterias/aislamiento & purificación , Enfermedades Transmitidas por los Alimentos/microbiología , Microscopía Fluorescente/métodos , HumanosRESUMEN
Foodborne pathogens remain a serious health issue in developed and developing countries. Safeness of food products has been assured for years with culture-based microbiological methods; however, these present several limitations such as turnaround time and extensive hands-on work, which have been typically address taking advantage of DNA-based methods such as real-time PCR (qPCR). These, and other similar techniques, are targeted assays, meaning that they are directed for the specific detection of one specific microbe. Even though reliable, this approach suffers from an important limitation that unless specific assays are design for every single pathogen potentially present, foods may be considered erroneously safe. To address this problem, next-generation sequencing (NGS) can be used as this is a nontargeted method; thus it has the capacity to detect every potential threat present. In this chapter, a protocol for the simultaneous detection and preliminary serotyping of Salmonella enterica serovar Enteritidis, Salmonella enterica serovar Typhimurium, Listeria monocytogenes, and Escherichia coli O157:H7 is described.
Asunto(s)
Microbiología de Alimentos , Enfermedades Transmitidas por los Alimentos , Secuenciación de Nucleótidos de Alto Rendimiento , Listeria monocytogenes , Microbiología de Alimentos/métodos , Secuenciación de Nucleótidos de Alto Rendimiento/métodos , Enfermedades Transmitidas por los Alimentos/microbiología , Enfermedades Transmitidas por los Alimentos/diagnóstico , Listeria monocytogenes/aislamiento & purificación , Listeria monocytogenes/genética , Escherichia coli O157/aislamiento & purificación , Escherichia coli O157/genética , Humanos , Serotipificación/métodos , ADN Bacteriano/genética , ADN Bacteriano/análisis , Salmonella typhimurium/aislamiento & purificación , Salmonella typhimurium/genéticaRESUMEN
Properly using controllable atmospheric containers can facilitate investigations of the survival abilities and physiological states of key and emerging-foodborne pathogens under recreated applicable food processing environmental conditions. Notably, saturated salt solutions can efficiently control relative humidity in airtight containers. This chapter describes a practical experimental setup, with necessary prerequisites for exposing foodborne pathogens to simulated and relevant food processing environmental conditions. Subsequent analyses for studying cell physiology will also be suggested.
Asunto(s)
Manipulación de Alimentos , Microbiología de Alimentos , Manipulación de Alimentos/métodos , Enfermedades Transmitidas por los Alimentos/microbiología , Viabilidad Microbiana , Bacterias/crecimiento & desarrollo , HumanosRESUMEN
Although MALDI-TOF mass spectrometry (MS) is considered as the gold standard for rapid and cost-effective identification of microorganisms in routine laboratory practices, its capability for antimicrobial resistance (AMR) detection has received limited focus. Nevertheless, recent studies explored the predictive performance of MALDI-TOF MS for detecting AMR in clinical pathogens when machine learning techniques are applied. This chapter describes a routine MALDI-TOF MS workflow for the rapid screening of AMR in foodborne pathogens, with Campylobacter spp. as a study model.
Asunto(s)
Campylobacter , Farmacorresistencia Bacteriana , Aprendizaje Automático , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción/métodos , Campylobacter/efectos de los fármacos , Antibacterianos/farmacología , Humanos , Microbiología de Alimentos/métodos , Pruebas de Sensibilidad Microbiana/métodos , Enfermedades Transmitidas por los Alimentos/microbiología , Bacterias/efectos de los fármacosRESUMEN
Like most microorganisms, important foodborne pathogenic bacteria, such as Salmonella enterica, Listeria monocytogenes, and several others as well, can attach to surfaces, of either abiotic or biotic nature, and create biofilms on them, provided the existence of supportive environmental conditions (e.g., permissive growth temperature, adequate humidity, and nutrient presence). Inside those sessile communities, the enclosed bacteria typically present a gene expression profile that differs from the one that would be displayed by the same cells growing planktonically in liquid media (free-swimming cells). This altered gene expression has important consequences on cellular physiology and behavior, including stress tolerance and induction of virulence. In this chapter, the methodology to use reverse transcription-quantitative polymerase chain reaction (RT-qPCR) to monitor and comparatively quantify expression changes in preselected genes of bacteria between planktonic and biofilm growth modes is presented.
Asunto(s)
Biopelículas , Plancton , Biopelículas/crecimiento & desarrollo , Plancton/genética , Regulación Bacteriana de la Expresión Génica , Microbiología de Alimentos , Perfilación de la Expresión Génica/métodos , Reacción en Cadena en Tiempo Real de la Polimerasa/métodos , Bacterias/genética , Listeria monocytogenes/genética , Listeria monocytogenes/fisiología , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa/métodosRESUMEN
The functional properties of biofilms are intimately related to their spatial architecture. Structural data are therefore of prime importance to dissect the complex social and survival strategies of biofilms and ultimately to improve their control. Confocal laser scanning microscopy (CLSM) is the most widespread microscopic tool to decipher biofilm structure, enabling noninvasive three-dimensional investigation of their dynamics down to the single-cell scale. The emergence of fully automated high content screening (HCS) systems, associated with large-scale image analysis, has radically amplified the flow of available biofilm structural data. In this contribution, we present a HCS-CLSM protocol used to analyze biofilm four-dimensional structural dynamics at high throughput. Meta-analysis of the quantitative variables extracted from HCS-CLSM will contribute to a better biological understanding of biofilm traits.
Asunto(s)
Biopelículas , Microscopía Confocal , Biopelículas/crecimiento & desarrollo , Microscopía Confocal/métodos , Microbiología de Alimentos/métodos , Imagenología Tridimensional/métodos , Enfermedades Transmitidas por los Alimentos/microbiología , Ensayos Analíticos de Alto Rendimiento/métodos , Procesamiento de Imagen Asistido por Computador/métodosRESUMEN
Next-generation sequencing revolutionized food safety management these last years providing access to a huge quantity of valuable data to identify, characterize, and monitor bacterial pathogens on the food chain. Shotgun metagenomics emerged as a particularly promising approach as it enables in-depth taxonomic profiling and functional investigation of food microbial communities. In this chapter, we provide a comprehensive step-by-step bioinformatical workflow to characterize bacterial ecology and resistome composition from metagenomic short-reads obtained by shotgun sequencing.
Asunto(s)
Bacterias , Biología Computacional , Microbiología de Alimentos , Secuenciación de Nucleótidos de Alto Rendimiento , Metagenómica , Metagenómica/métodos , Biología Computacional/métodos , Microbiología de Alimentos/métodos , Bacterias/genética , Secuenciación de Nucleótidos de Alto Rendimiento/métodos , Metagenoma , Microbiota/genéticaRESUMEN
Metabolomics is the study of low molecular weight biochemical molecules (typically <1500 Da) in a defined biological organism or system. In case of food systems, the term "food metabolomics" is often used. Food metabolomics has been widely explored and applied in various fields including food analysis, food intake, food traceability, and food safety. Food safety applications focusing on the identification of pathogen-specific biomarkers have been promising. This chapter describes a nontargeted metabolite profiling workflow using gas chromatography coupled with mass spectrometry (GC-MS) for characterizing three globally important foodborne pathogens, Escherichia coli O157:H7, Listeria monocytogenes, and Salmonella enterica, from selective enrichment liquid culture media. The workflow involves a detailed description of food spiking experiments followed by procedures for the extraction of polar metabolites from media, the analysis of the extracts using GC-MS, and finally chemometric data analysis using univariate and multivariate statistical tools to identify potential pathogen-specific biomarkers.
Asunto(s)
Biomarcadores , Microbiología de Alimentos , Cromatografía de Gases y Espectrometría de Masas , Listeria monocytogenes , Metabolómica , Metabolómica/métodos , Cromatografía de Gases y Espectrometría de Masas/métodos , Biomarcadores/análisis , Microbiología de Alimentos/métodos , Listeria monocytogenes/metabolismo , Listeria monocytogenes/aislamiento & purificación , Salmonella enterica/metabolismo , Escherichia coli O157/metabolismo , Escherichia coli O157/aislamiento & purificación , Enfermedades Transmitidas por los Alimentos/microbiología , MetabolomaRESUMEN
Rapid screening for foodborne pathogens is crucial for food safety. A rapid and one-step electrochemical sensor has been developed for the detection of Escherichia coli (E. coli), Staphylococcus aureus (S. aureus) and Salmonella typhimurium (S. typhimurium). Through the construction of aptamer/two-dimensional carboxylated Ti3C2Tx (2D C-Ti3C2Tx)/two-dimensional Zn-MOF (2D Zn-MOF) composites, the recognition elements, signal tags, and signal amplifiers are integrated on the electrode surface. Pathogens are selectively captured using the aptamer, which increases the impedance of the electrode surfaceï¼leads to a decrease in the 2D Zn-MOF current. Bacteria can be rapidly quantified using a one-step detection method and the replacement of aptamers. The detection limits for E. coli, S. aureus, and S. typhimurium are 6, 5, and 5 CFU·mL-1, respectively. The sensor demonstrated reliable detection capabilities in real-sample testing. Therefore, the one-step sensor based on the 2D Zn-MOF and 2D C-Ti3C2Tx has significant application value in the detection of foodborne pathogens.
Asunto(s)
Técnicas Electroquímicas , Escherichia coli , Salmonella typhimurium , Staphylococcus aureus , Zinc , Staphylococcus aureus/aislamiento & purificación , Salmonella typhimurium/aislamiento & purificación , Zinc/análisis , Escherichia coli/aislamiento & purificación , Técnicas Electroquímicas/instrumentación , Técnicas Biosensibles/instrumentación , Estructuras Metalorgánicas/química , Microbiología de Alimentos , Titanio/química , Límite de Detección , Electrodos , Contaminación de Alimentos/análisisRESUMEN
The spoilage of irradiated ready-to-eat chicken feet (RTECF) seriously affects the food's quality, resulting in package swelling and off-flavors, both of which are highly undesirable to stakeholders and consumers. To investigate the spoilage characteristics of irradiated RTECF and the microorganisms responsible for the spoilage and swelling, the changes in physicochemical properties, microbial community, and volatile organic compounds (VOCs) between normal and spoiled RTECF were evaluated. Compared with normal samples, the spoiled RTECF showed a higher pH value and total volatile basic nitrogen (TVB-N) value, lower color value, and texture features (P < 0.05). Acinetobacter, Pseudomonas, Lactobacillus, and Candida were the dominant genera responsible for RTECF spoilage as confirmed through both culture-dependent methods and high-throughput sequencing (HTS). The results of the verification for gas-producing strains showed that Lactobacillus brevis could cause RTECF packaging to swell. A total of 20 key VOCs were identified using headspace solid-phase microextraction combined with gas chromatography-mass spectrometry (HS-SPME-GC-MS). The results of Pearson correlation analysis (|r|>0.8, P < 0.05) showed that 12 dominant core microbial genera had a significant effect on the flavor of RTECF before and after spoilage. This study provides a theoretical reference for solving the problem of RTECF spoilage and improving the overall quality of RTECF products.
Asunto(s)
Bacterias , Pollos , Irradiación de Alimentos , Microbiología de Alimentos , Compuestos Orgánicos Volátiles , Pollos/microbiología , Animales , Compuestos Orgánicos Volátiles/análisis , Compuestos Orgánicos Volátiles/química , Compuestos Orgánicos Volátiles/metabolismo , Bacterias/clasificación , Bacterias/efectos de la radiación , Bacterias/aislamiento & purificación , Bacterias/genética , Bacterias/crecimiento & desarrollo , Bacterias/metabolismo , Irradiación de Alimentos/métodos , Microbiota/efectos de la radiación , Embalaje de Alimentos/métodos , Cromatografía de Gases y Espectrometría de Masas , Concentración de Iones de Hidrógeno , Comida Rápida/microbiología , Comida Rápida/análisisRESUMEN
Salmonella is a major bacterial concern for public health globally. Although there are limited documentation on the prevalence of Salmonella species in Cambodia's food chain, some reports indicate that salmonellosis is a severe gastrointestinal infection in its population and especially in children. To investigate the presence of Salmonella spp., 285 food samples (75 meat, 50 seafood, and 160 leafy green vegetable samples) were randomly collected from various local markets in Phnom Penh capital and nearby farms in Cambodia. Concurrently, field observations were conducted to collect data on food hygiene and practices among the relevant actors. All food samples were analyzed using bacterial culture and plate counts, and the findings were confirmed serially with biochemical, serological, and PCR tests. The observational data on food hygiene and practices from farm to market revealed that the spread of Salmonella in the food-value chain from farm to market could pose health risks to consumers. The overall prevalence of Salmonella spp. was 48.4% (138/285), while the prevalence in meat, seafood, and vegetables was 71% (53/75), 64% (32/50), and 33% (53/160), respectively. Mean Salmonella plate count ranged from 1.2 to 7.40 log10 CFU/g, and there was no significant difference in bacterial counts between meat, seafood, and vegetable samples (p > 0.05). The most common serogroups among the isolated Salmonella spp. were B and C. These results suggest that a large proportion of meat, seafood, and vegetable products sold at local markets in Phnom Penh are contaminated with Salmonella spp. This is likely linked to inadequate hygiene and sanitation practices, including handling, storage, and preservation conditions. Observations on farms suggested that the prevalence of Salmonella in vegetables sold at the market could be linked to contamination relating to agricultural practices. Thus, controlling the spread of foodborne salmonellosis through the food-value chain from farms and retailers to consumers is warranted to enhance food safety in Cambodia.
Asunto(s)
Granjas , Contaminación de Alimentos , Carne , Salmonella , Alimentos Marinos , Verduras , Cambodia/epidemiología , Verduras/microbiología , Salmonella/aislamiento & purificación , Salmonella/clasificación , Contaminación de Alimentos/análisis , Contaminación de Alimentos/estadística & datos numéricos , Prevalencia , Alimentos Marinos/microbiología , Carne/microbiología , Animales , Microbiología de Alimentos , Humanos , HigieneRESUMEN
This study aimed to assess the impact of adaptation of ten strains of O157:H7 and non-O157 Escherichia coli to low pH (acid shock or slow acidification) and the effects of this exposure or not on the resistance of E. coli strains to UV radiation in orange juice (pH 3.5). The acid-shocked cells were obtained through culture in tryptic soy broth (TSB) with a final pH of 4.8, which was adjusted by hydrochloric, lactic, or citric acid and subsequently inoculated in orange juice at 4 °C for 30 days. No significant differences (p > 0.05) in survival in orange juice were observed between the serotypes O157:H7 and non-O157:H7 for acid-shocked experiments. After slow acidification, where the cells were cultured in TSB supplemented with glucose 1% (TSB + G), a significant increase (p < 0.05) in survival was observed for all strains evaluated. The D-values (radiation dose (J/cm2) necessary to decrease the microbial population by 90%) were determined as the inverse of the slopes of the regressions (k) obtained by plotting log (N/N0). The results show that among the strains tested, E. coli O157:H7 (303/00) and O26:H11 were the most resistant and sensitive strains, respectively. According to our results, the method of acid adaptation contributes to increasing the UV resistance for most of the strains tested.
Asunto(s)
Adaptación Fisiológica , Citrus sinensis , Escherichia coli O157 , Jugos de Frutas y Vegetales , Rayos Ultravioleta , Escherichia coli O157/efectos de la radiación , Escherichia coli O157/crecimiento & desarrollo , Escherichia coli O157/efectos de los fármacos , Jugos de Frutas y Vegetales/microbiología , Jugos de Frutas y Vegetales/análisis , Citrus sinensis/microbiología , Citrus sinensis/química , Concentración de Iones de Hidrógeno , Escherichia coli/efectos de la radiación , Escherichia coli/efectos de los fármacos , Ácidos/farmacología , Recuento de Colonia Microbiana , Microbiología de Alimentos , Viabilidad Microbiana/efectos de la radiación , Viabilidad Microbiana/efectos de los fármacos , Irradiación de AlimentosRESUMEN
This study aimed to assess the bacterial microbiota involved in the spoilage of pacu (Piaractus mesopotamics), patinga (female Piaractus mesopotamics x male Piaractus brachypomus), and tambacu (female Colossoma macropomum × male Piaractus mesopotamics) during ice and frozen storage. Changes in the microbiota of three fish species (N = 22) during storage were studied through 16S rRNA amplicon-based sequencing and correlated with volatile organic compounds (VOCs) and metabolites assessed by nuclear magnetic resonance (NMR). Storage conditions (time and temperature) affected the microbiota diversity in all fish samples. Fish microbiota comprised mainly of Pseudomonas sp., Brochothrix sp., Acinetobacter sp., Bacillus sp., Lactiplantibacillus sp., Kocuria sp., and Enterococcus sp. The relative abundance of Kocuria, P. fragi, L. plantarum, Enterococcus, and Acinetobacter was positively correlated with the metabolic pathways of ether lipid metabolism while B. thermosphacta and P. fragi were correlated with metabolic pathways involved in amino acid metabolism. P. fragi was the most prevalent spoilage bacteria in both storage conditions (ice and frozen), followed by B. thermosphacta. Moreover, the relative abundance of identified Bacillus strains in fish samples stored in ice was positively correlated with the production of VOCs (1-hexanol, nonanal, octenol, and 2-ethyl-1-hexanol) associated with off-flavors. 1H NMR analysis confirmed that amino acids, acetic acid, and ATP degradation products increase over (ice) storage, and therefore considered chemical spoilage index of fish fillets.
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Bacterias , Peces , Almacenamiento de Alimentos , Congelación , Microbiota , ARN Ribosómico 16S , Alimentos Marinos , Compuestos Orgánicos Volátiles , Animales , Bacterias/clasificación , Bacterias/genética , Bacterias/aislamiento & purificación , Bacterias/metabolismo , Compuestos Orgánicos Volátiles/análisis , Compuestos Orgánicos Volátiles/metabolismo , Peces/microbiología , Brasil , Alimentos Marinos/microbiología , Alimentos Marinos/análisis , ARN Ribosómico 16S/genética , Hielo , Microbiología de Alimentos , Biodiversidad , FemeninoRESUMEN
Escherichia coli O157:H7 is a pathogenic serotype of Escherichia coli. Consumption of food contaminated with E. coli O157:H7 could cause a range of diseases. Therefore, it is of great importance to establish rapid and accurate detection methods for E. coli O157:H7 in food. In this study, based on LAMP and combined with the CRISPR/cas12a system, a sensitive and specific rapid detection method for E. coli O157:H7 was established, and One-Pot detection method was also constructed. The sensitivity of this method could stably reach 9.2 × 10° CFU/mL in pure culture, and the whole reaction can be completed within 1 h. In milk, E. coli O157:H7 with an initial contamination of 7.4 × 10° CFU/mL only needed to be cultured for 3 h to be detected. The test results can be judged by the fluorescence curve or by visual observation under a UV lamp, eliminating instrument limitations and One-Pot detection can effectively prevent the problem of false positives. In a word, the LAMP-CRISPR/cas12a system is a highly sensitive and convenient method for detecting E. coli O157:H7.
Asunto(s)
Sistemas CRISPR-Cas , Escherichia coli O157 , Microbiología de Alimentos , Leche , Técnicas de Amplificación de Ácido Nucleico , Escherichia coli O157/genética , Escherichia coli O157/aislamiento & purificación , Leche/microbiología , Microbiología de Alimentos/métodos , Técnicas de Amplificación de Ácido Nucleico/métodos , Animales , Sensibilidad y Especificidad , Contaminación de Alimentos/análisis , Técnicas de Diagnóstico Molecular/métodosRESUMEN
Objective: To investigate the cause of a foodborne outbreak that occurred in Dong Nai province, Viet Nam, in 2024, and implement control measures. Methods: An initial investigation was conducted to confirm the outbreak, which was followed by epidemiological and environmental investigations to find the plausible causative food item. Clinical specimens and food samples were tested to identify the pathogen. Results: A total of 547 symptomatic cases were recorded, of whom two were in severe condition requiring extracorporeal membrane oxygenation and ventilation, one of whom died. Among 99 interviewed cases, the mean incubation time was 9 hours (range 2-24 hours), with the main symptoms being fever, abdominal pain, diarrhoea and vomiting. All patients had eaten banh mi from a local bakery. Salmonella spp. were identified in food samples and clinical specimens. The bakery halted production, and the outbreak ended after 1 week. Discussion: All the patients were exposed to only one food in common, which facilitated the investigation process. This outbreak is a reminder to small retailers and take-away shops of the importance of food safety management in preventing similar future outbreaks. All food handlers must comply with food hygiene principles, especially in hot temperatures, which boosts bacterial growth.
Asunto(s)
Brotes de Enfermedades , Intoxicación Alimentaria por Salmonella , Humanos , Vietnam/epidemiología , Masculino , Adulto , Femenino , Intoxicación Alimentaria por Salmonella/epidemiología , Intoxicación Alimentaria por Salmonella/microbiología , Persona de Mediana Edad , Preescolar , Niño , Adolescente , Lactante , Salmonella/aislamiento & purificación , Adulto Joven , Enfermedades Transmitidas por los Alimentos/epidemiología , Enfermedades Transmitidas por los Alimentos/microbiología , Microbiología de Alimentos , AncianoRESUMEN
Foodborne harmful bacteria not only cause waste of fresh food, but also pose a major threat to human health. Among many new sterilization and preservation technologies, photodynamic inactivation (PDI) has the advantages of low-cost, broad-spectrum, energy-saving, nontoxic, and high efficiency. In particular, PDI based on edible photosensitizers (PSs) has a broader application prospect due to edible, accessible, and renewable features, it also can maximize the retention of the nutritional characteristics and sensory quality of the food. Therefore, it is meaningful and necessary to review edible PSs and edible PSs-mediated PDI, which can help to arouse interest and concern and promote the further development of edible PSs-mediated PDI in the future field of nonthermally sterilized food preservation. Herein, the classification and modification of edible PSs, PS-mediated in vivo and PS-mediated in vitro mechanism of PDI, strengthening strategy to improve PDI efficiency by the structure change synergistic and multitechnical means, as well as the application in fresh food preservation were reviewed systematically. Finally, the deficiency and possible future perspectives of edible PSs-mediated PDI were articulated. This review aimed to provide new perspective for the future food preservation and microbial control.