Molecular Techniques for Detection of Food-Borne Bacteria and for Assessment of Bacterial Quality

2014 ◽  
pp. 134-161
Keyword(s):  
Molecular Techniques ◽  
Food Borne

scholarly journals Élelmiszer-biztonsági jelentőségű baktériumok molekuláris detektálásának fejlesztése miniatürizált mikrofluidikai eszközök segítségével

2015 ◽  
Vol 156 (51) ◽  
pp. 2082-2088
Author(s):  
Kristóf Iván ◽  
Anna Maráz
Keyword(s):  
Polymerase Chain Reaction ◽  
Pathogenic Bacteria ◽  
Lab On A Chip ◽  
Dna Amplification ◽  
Molecular Techniques ◽  
Microbiological Analysis ◽  
Chain Reaction ◽  
Detection And Identification ◽  
Food Borne ◽  
Polymerase Chain

Detection and identification of food-borne pathogenic bacteria are key points for the assurance of microbiological food safety. Traditional culture-based methods are more and more replaced by or supplemented with nucleic acid based molecular techniques, targeting specific (preferably virulence) genes in the genomes. Internationally validated DNA amplification – most frequently real-time polymerase chain reaction – methods are applied by the food microbiological testing laboratories for routine analysis, which will result not only in shortening the time for results but they also improve the performance characteristics (e.g. sensitivity, specificity) of the methods. Beside numerous advantages of the polymerase chain reaction based techniques for routine microbiological analysis certain drawbacks have to be mentioned, such as the high cost of the equipment and reagents, as well as the risk of contamination of the laboratory environment by the polymerase chain reaction amplicons, which require construction of an isolated laboratory system. Lab-on-a-chip systems can integrate most of these laboratory processes within a miniaturized device that delivers the same specificity and reliability as the standard protocols. The benefits of miniaturized devices are: simple – often automated – use, small overall size, portability, sterility due to single use possibility. These miniaturized rapid diagnostic tests are being researched and developed at the best research centers around the globe implementing various sample preparation and molecular DNA amplification methods on-chip. In parallel, the aim of the authors’ research is to develop microfluidic Lab-on-a-chip devices for the detection and identification of food-borne pathogenic bacteria. Orv. Hetil., 2015, 156(51), 2082–2088.

Emerging pathogens: Isospora, Cyclospora and microsporidia

Parasitology ◽  
1999 ◽  
Vol 117 (7) ◽  
pp. 143-159 ◽  
Author(s):  
A. CURRY ◽  
H. V. SMITH
Keyword(s):  
Molecular Techniques ◽  
Diagnostic Methods ◽  
Clinical Samples ◽  
Polymorphism Analysis ◽  
Human Pathogens ◽  
Emerging Pathogens ◽  
Dna Diagnosis ◽  
Food Borne ◽  
Intracellular Parasites ◽  
Traveller’S Diarrhoea

Isospora belli, Cyclospora cayetanensis as well as several species of microsporidia are recognized as emerging protozoan pathogens of humans. All are obligate intracellular parasites, with Isospora and the microsporidia being primarily associated with immunocompromised hosts. Cyclospora is a cause of traveller's diarrhoea, and is responsible for water-borne and food-borne outbreaks of disease. Drug treatment is available for these infections. Improved diagnostic methods including the autofluorescence of I. belli and C. cayetanensis oocysts have assisted in the routine detection of these pathogens. Since the recognition of immunosuppression due to HIV infection, microsporidia have become recognized as important human pathogens with a continuing expansion of the parasite-associated clinico-pathological spectrum. The small size, intracellular nature and poor staining properties with many histological stains result in under-reporting of microsporidial infections. Trichrome stain and optical brighteners are used to detect spores in faeces, urines, respiratory secretions and other aspirates. Electron microscopy remains an important diagnostic method but its sensitivity is relatively poor. Molecular techniques should overcome current diagnostic limitations. The ability to extract DNA and amplify by PCR directly from clinical samples has increased the usefulness of molecular methods. Restriction fragment length polymorphism analysis of amplicons can be used to determine genus, species and strain types of various microsporidia. Increased specificity is required in primer design because current primers used for amplifying non-microsporidian DNA also amplify microsporidian DNA. Diagnosis and pathogen characterisation rely increasingly on PCR-based approaches, and the sequence analysis approach becomes increasingly feasible and affordable. However, robust, reliable and sensitive methods are still required for dissecting pathogenesis, epidemiology, transmission routes and sources of infections.

scholarly journals Detection of Aspergillus flavus using PCR method from fungus infested food grains collected from local market

2018 ◽  
Vol 7 (2) ◽  
pp. 2073 ◽  
Author(s):  
Renu Khare ◽  
Agarwal M.K. ◽  
Sameer S. Bhagayavant ◽  
Poonam Verma ◽  
Nagar D.P.
Keyword(s):  
Aspergillus Flavus ◽  
Health And Safety ◽  
Epidemiological Data ◽  
Economic Loss ◽  
Food Samples ◽  
Molecular Techniques ◽  
Local Market ◽  
Food Grains ◽  
Food Borne Pathogens ◽  
Food Borne

India is an agrarian country two-thirds of its population is engaged directly or indirectly in agricultural activities. In recent years many food borne pathogens have become major threat to public health and safety.  The consumption of contaminated food grains or products has been considered to be the leading source of human food borne infections. Surveillance studies have provided data and a better understanding into the existence and spread of food borne pathogens. Aflatoxins produced by Aspergillus species are important toxic secondary metabolites known for their impacts on animal and human health, and their effects on the economic loss of key grain and nut crops. Several molecular techniques (including multilocus sequence typing, pulsed field gel electrophoresis, DNA sequencing, multiplex PCR, RAPD, and many more) are available for detection and characterisation of pathogenic microorganisms from food samples, which provide reliable epidemiological data for tracing the source of infections. Present study highlights the possible use of PCR technique, in surveillance and detection of A. flavus in fungal infested food grains. The current study was carried out to elucidate the infestation of aflatoxin producing fungus on both kharif (groundnut, rice and maize) and Rabi crops (wheat, gram and soybean). Total 15 samples were collected randomly from local market of Gwalior (M.P). Out of fifteen only nine (60%) samples were found to be Aspergillus positive. Seven samples were infested by Aspergillus flavus and two by A. niger. The selected fungal isolates were identified by amplifying aflR gene of A. flavus in Thermo Cycler.

scholarly journals Advancements in methods to detect and culture medically important anaerobic bacteria

2021 ◽  
Vol 3 (2) ◽  
Author(s):  
Javaria Badar ◽  
Muhammad Zaid ◽  
Yasir Rehman
Keyword(s):  
Foodborne Pathogens ◽  
Rapid Detection ◽  
Anaerobic Bacteria ◽  
Delayed Diagnosis ◽  
Rapid Identification ◽  
Molecular Techniques ◽  
Food Borne ◽  
Culture Independent ◽  
Food Borne Illness ◽  
Cultivation Techniques

Anaerobic bacteria are one of the most important bacteria, involved in a number of diseases and infections. These are also involved in food borne illness. Due to their fastidious nature, culturing anaerobic bacteria is a bit difficult task. Moreover, anaerobic bacteria can take several days and weeks to grow in laboratories. Apart from this, most bacteria just cannot be cultured in laboratories using standard (anaerobic) cultivation techniques known so far. Difficulties in microbiological detection result in delayed diagnosis of the diseases. Many patients suffer due to these facts, as rapid identification is not only difficult, but in many cases, is almost impossible. Thus, there is a need to develop novel techniques for the cultivation and identification of clinically important anaerobes. Rapid detection of foodborne pathogens is necessary for the prevention of foodborne disease and for the safe supply of food. Present article reviews and discusses advance techniques, both culture-dependent and culture-independent, that allow rapid detection of such important anaerobic bacteria. Advancements in culturing techniques has reduced the time to grow the anaerobic bacteria in laboratories. Whereas advancements in molecular techniques have enabled the rapid detection of medically important anaerobes including Clostridium, Bacteroides, and many others.

scholarly journals Review on Major Food-Borne Zoonotic Bacterial Pathogens

2020 ◽  
Vol 2020 ◽  
pp. 1-19 ◽  
Author(s):  
Engidaw Abebe ◽  
Getachew Gugsa ◽  
Meselu Ahmed
Keyword(s):  
Public Health ◽  
Developing Countries ◽  
Bacterial Pathogens ◽  
Molecular Techniques ◽  
Animal Origin ◽  
Animal Products ◽  
Major Food ◽  
Food Borne ◽  
Causative Agents ◽  
Zoonotic Bacteria

Food-borne microorganisms are major pathogens affecting food safety and cause human illness worldwide as a result of consumption of foodstuff, mainly animal products contaminated with vegetative pathogens or their toxins. Most of these microbes have zoonotic importance resulting in significant impact on both public health and economic sectors. Bacteria are the causative agents of two-thirds of human food-borne diseases worldwide with high burden in developing countries. Hence, the objectives of this review paper are to highlight the background of food-borne bacterial pathogens and to review common major food-borne zoonotic bacterial pathogens. Food animals are the major reservoirs of many food-borne zoonotic bacterial pathogens, and food products of animal origin are the main vehicles of transmission. Meat, dairy products, and eggs are the main ways by which people are exposed to zoonotic bacteria. S. aureus, Salmonella species, Campylobacter species, L. monocytogenes, and E. coli are the major zoonotic bacterial pathogens which are the causative agents of food-borne illness and death in the world associated with consumption of contaminated animal products. Production of toxins and structural virulent factors are responsible for the pathogenesis of these bacteria. These major zoonotic bacteria cause human infections which are characterized mainly by gastrointestinal symptoms including nausea, vomiting, diarrhea, abdominal cramps, and other agent-specific symptoms. Some bacteria may cause severe complications. Conventional (culturing), serological, and molecular techniques are important for detection of these common zoonotic bacteria and their toxins in food. Good hygiene, GMP, sanitation in operating procedures, and implementation of standardized HACCP and pasteurization procedures are effective methods for the control and prevention. Currently, the emergence of multidrug-resistant zoonotic bacteria associated with consumption of contaminated animal products is a great concern for the public health, and there should be coordinated surveillance and monitoring system for food-borne zoonotic bacterial pathogens particularly in developing countries including Ethiopia.

Multimode light microscopy and fluorescence-based reagents as tools for the study of chemical and molecular dynamics of living cells and tissues

1992 ◽  
Vol 50 (1) ◽  
pp. 418-419
Author(s):  
D. L. Taylor
Keyword(s):  
Living Cells ◽  
Cellular Level ◽  
Molecular Techniques ◽  
Cellular Functions ◽  
Macromolecular Assemblies ◽  
Cell Functions ◽  
Molecular Events ◽  
Yield Information ◽  
Full Knowledge ◽  
Structural Methods

Cells function through the complex temporal and spatial interplay of ions, metabolites, macromolecules and macromolecular assemblies. Biochemical approaches allow the investigator to define the components and the solution chemical reactions that might be involved in cellular functions. Static structural methods can yield information concerning the 2- and 3-D organization of known and unknown cellular constituents. Genetic and molecular techniques are powerful approaches that can alter specific functions through the manipulation of gene products and thus identify necessary components and sequences of molecular events. However, full knowledge of the mechanism of particular cell functions will require direct measurement of the interplay of cellular constituents. Therefore, there has been a need to develop methods that can yield chemical and molecular information in time and space in living cells, while allowing the integration of information from biochemical, molecular and genetic approaches at the cellular level.

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