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1.
Crit Rev Toxicol ; 53(2): 117-130, 2023 02.
Artigo em Inglês | MEDLINE | ID: mdl-37278984

RESUMO

Mycotoxins, which are natural toxic compounds produced by filamentous fungi, are considered major contaminants in the food and feed chain due to their stability during processing. Their impacts in food and feedstuff pollution were accentuated due the climate change in the region. They are characterized by their toxicological effects on human and animal health but also by their harmful economic impact. Mediterranean countries: Algeria, Egypt, Libya, Morocco and Tunisia are characterized by high temperatures and high relative humidity, particularly in littoral regions that provide favorable conditions for fungal growth and toxinogenesis. Many scientific papers have been published recently in these countries showing mycotoxin occurrence in different commodities and an attempt at bio-detoxification using many bio-products. In order to minimize the bioavailability and/or to detoxify mycotoxins into less toxic metabolites (bio-transforming agents), safe and biological methods have been developed including the use of lactic acid bacteria, yeasts, plant extracts and clays minerals from Mediterranean regions. The aim of this review is to present the pollution of mycotoxins in food and feedstuff of humans and animals and to discuss the development of effective biological control for mycotoxin removal/detoxification and prevention using bio-products. This review will also elucidate the new used natural products to be considered as a new candidates for mycotoxins detoxification/prevention on animal feedstuffs.


Assuntos
Micotoxinas , Animais , Humanos , Micotoxinas/toxicidade , Contaminação de Alimentos/prevenção & controle , Ração Animal , Poluição Ambiental
2.
Food Addit Contam Part B Surveill ; 16(3): 274-287, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37387604

RESUMO

Twenty two mycotoxins in 136 durum wheat collected from Tunisia in 2020 and 2021 were investigated. Mycotoxins were analyzed by UHPLCMS/MS. In 2020, 60.9% of the samples were contaminated with Aflatoxin B1 (AFB1) and/or enniatin. Whereas, in 2021, 34.4% were contaminated by enniatins. AFB1 was detected only in 2020, in the continental region (6/46) and all samples exceeded limits. AFB1 was detected in stored wheat (24-37.8 µg/kg) but also in pre-stored wheat (17-28.4 µg/kg) and in one sample collected in the field (21 µg/kg). Enniatin A1, enniatin B and enniatin B1 were detected in wheat collected in the field (30-7684 µg/kg), pre-storage (42-1266 µg/kg) and storage (65.8-498.2 µg/kg) from the continental region also, in sample collected in pre-storage (31.3-1410 µg/kg) and at harvest (48- 1060 µg/kg). Samples had a water activity less than 0.7 and moisture content ranged between 09-14%. AFB1 level represent a health risk to the Tunisian consumers.


Assuntos
Micotoxinas , Micotoxinas/análise , Triticum , Tunísia , Contaminação de Alimentos/análise , Aflatoxina B1
3.
World J Microbiol Biotechnol ; 39(5): 128, 2023 Mar 21.
Artigo em Inglês | MEDLINE | ID: mdl-36943491

RESUMO

The aim of this study was to determine the microbial diversity and mycotoxin profile of artisanal infant flours commonly vended in public healthcare centres and retail markets in Côte d'Ivoire. Thus, maize, millet, sorghum, soya and multigrain (mix of different cereals) flour samples collected from different localities were first, analysed for nutritional composition, then for microbial communities using high-throughput sequencing and for mycotoxins through UHPLC-MS/MS method. Firmicutes was the most abundant bacterial phylum and the dominant genera were Weissella, Staphylococcus, Pediococcus. Potential pathogenic genera such as Bacillus, Enterobacter, Acinetobacter and Burkholderia were also found. The fungal community was composed of two dominant phyla (Ascomycota and Basidiomycota) and 31 genera with > 0.1% relative abundance. In samples from public healthcare centres, Candida, Hyphopichia, Trichosporon, and Cyberlindnera were the most dominant genera according to the flour type while in samples from retail markets, they were Cyberlindnera, Clavispora, Nakaseomyces, Aureobasidium and Candida. Possible toxigenic genera Fusarium and Aspergillus were also detected. Aflatoxin B1 (AFB1), Ochractoxin (OTA), Fumonisin B1 (FB1) and B2 (FB2) were the mycotoxins found in the analysed flours. AFB1 was detected in 100% of maize (range 1.2-120.5 µg/kg; mean: 44.2 µg/kg) and 50-83.3% of millet flours (range 0.2-31.5 µg/kg; mean: 31.5 µg/kg). Its level in all maize and rice flour samples exceeded EU standard (0.1 µg/kg). For OTA and fumonisins, millet and maize flours showed the highest levels of sample exceeding the EU standard. Thus, artisanal infant flours marketed in Côte d'Ivoire, mainly maize and rice flours, although containing potentially beneficial bacteria, represent potential health risks for children.


Assuntos
Microbiota , Micotoxinas , Ocratoxinas , Criança , Lactente , Humanos , Farinha/análise , Ocratoxinas/análise , Côte d'Ivoire , Espectrometria de Massas em Tandem , Contaminação de Alimentos/análise , Grão Comestível , Zea mays/microbiologia
4.
Folia Microbiol (Praha) ; 68(2): 257-275, 2023 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-36264452

RESUMO

Adjuevan is an Ivorian traditional fermented fish used as a condiment. However, the fermentation process and storage conditions may lead to the production of biogenic amines (BA) which can induce severe human toxicological effects. Thus, this study aimed to reveal the bacterial community diversity and the BA contents during the storage. Samples of adjuevan from the fish species Chloroscombrus chrysurus, Galeoides decadactylus, and Thunnus thynnus were collected from local producers, stored at ambient temperature (28-30 °C) and in a refrigerator (4 °C) over a period of 8 weeks. At 2-week intervals, BA were determined by HPLC and the bacterial communities analyzed using high-throughput sequencing (NGS) of the V3-V4 region of the 16S rRNA gene. Results showed that histamine, cadaverine, putrescine, and tyramine were the major compounds. In adjuevan from T. thynnus, the level of histamine was over the maximum level of 200 mg/kg determined by Codex Alimentarius. For the other amines, no safety concerns are related. In total, 21 bacterial genera with a relative abundance ≥ 1% and belonging to 14 families and 5 phyla were detected. The Bacillaceae family was the most found at ambient temperature while Staphylococcaceae and Enterococcaceae were the most abundant in a refrigerator. The analysis of correlation showed that the increase of Lentibacillus leads to a decrease of the major BA at ambient temperature. On the contrary, the increase of Staphylococcus, Lactobacillus, Psychrobacter, Peptostreptococcus, and Fusobacterium leads to an increase of these biogenic compounds. Thus, Lentibacillus acted as BA-oxidizing bacteria while the others were found as BA-producing bacteria during adjuevan storage.


Assuntos
Aminas Biogênicas , Histamina , Humanos , Animais , Histamina/análise , RNA Ribossômico 16S/genética , Côte d'Ivoire , Aminas Biogênicas/análise , Bactérias/genética , Fermentação , Peixes/genética
5.
J Fungi (Basel) ; 8(2)2022 Jan 26.
Artigo em Inglês | MEDLINE | ID: mdl-35205871

RESUMO

The antifungal and antiaflatoxinogenic activities of the essential oils (EOs) from the leaves of Cymbopogon schoenanthus, Cymbopogon citratus, Cymbopogon nardus, and their pair combinations were investigated. Antifungal susceptibility and the efficacy of paired combinations of EOs were assessed using agar microdilution and checkerboard methods, respectively. Identification and quantification of chemical components of the EOs were carried out by gas chromatography-mass spectrometry and gas chromatography-flame ionization detector (GC-MS and GC-FID), respectively. Aflatoxins were separated and identified by High-Performance Liquid Chromatography (HPLC) and then quantified by spectrofluorescence. The EO of C. nardus exhibited the highest inhibitory activity against Aspergillus flavus and Aspergillus parasiticus. The combination of C. citratus and C. nardus and that of C. nardus and C. schoenanthus exhibited a synergistic effect against Aspergillus flavus and Aspergillus, respectively. Both C. citratus and C. schoenanthus EOs totally inhibited the synthesis of aflatoxin B1 at 1 µL/mL. C. citratus blocked the production of aflatoxins B2 and G2 at 0.5 µL/mL. Both C. citratus and C. schoenanthus totally hampered the production of the aflatoxin G1 at 0.75 µL/mL. The combination of C. citratus and C. schoenanthus completely inhibited the production of the four aflatoxins. The study shows that the combinations can be used to improve their antifungal and antiaflatoxinogenic activities.

6.
World J Microbiol Biotechnol ; 37(2): 24, 2021 Jan 11.
Artigo em Inglês | MEDLINE | ID: mdl-33427964

RESUMO

In order to phenotypically characterized Saccharomyces cerevisiae strains isolated from sorghum beer and palm wines for a possible selection of a starter culture, 30 strains were tested for killer activity, temperature resistance, ethanol tolerance, carbohydrate fermentation, enzyme profile and sorghum wort fermentation. Of the tested strains, three showed a killer profile, while four showed a neutral profile and 23 were found to be sensitive to K2 toxin. Temperatures of 40 °C and 44 °C allowed to distinguish strains into four thermal groups with only three strains may grow at 44 °C. Almost tested strains were tolerant to 5% ethanol with viability rates up to 73%. But at 10% and 15% ethanol, respectively 18 and 7 strains were tolerant. Carbohydrate fermentation revealed 13 fermentation profiles, including one typical and 12 atypical profiles. The typical profile strains (16.13% of the strains) fermented glucose, galactose, fructose, sucrose, maltose, trehalose and raffinose. Most of the strains secreted lipases (mainly esterase and esterase-lipase), proteases (mainly valine and cysteine arylamidase, chrymotrypsin) and phosphatases (mainly acid phosphatase and naphthol phosphohydrolase). On contrary, only five strains isolated from sorghum beer exhibited glucosidase activity, mainly α-glucosidase. The analyse of fermented sorghum wort revealed that fermentative performance is strain dependent. Furthermore, the Hierarchical Cluster Analysis showed that the strains were separated in three distinct clusters with the strains from sorghum beer clustered separately.


Assuntos
Cerveja/microbiologia , Saccharomyces cerevisiae/isolamento & purificação , Saccharomyces cerevisiae/fisiologia , Sorghum/microbiologia , Vinho/microbiologia , Tolerância a Medicamentos , Etanol/farmacologia , Fermentação , Maltose , Saccharomyces cerevisiae/efeitos dos fármacos , Saccharomyces cerevisiae/enzimologia , Temperatura
7.
Prev Nutr Food Sci ; 25(1): 98-107, 2020 Mar 31.
Artigo em Inglês | MEDLINE | ID: mdl-32292762

RESUMO

This study identified biogenic amines, fatty acids, and volatile compounds in adjuevan, an Ivorian traditionally salted and fermented fish. Samples were obtained from two processing methods (method 1: entire fish adjuevan; method 2: both sides filleted adjuevan) with the fish species Galeoides decadactylus. Biogenic amines found in freshly produced adjuevan were histamine, putrescine, cadaverine, tyramine, ß-phenyl ethylamine, and spermidine. Among these, the most prevalent were ß-phenyl ethylamine and cadaverine. Biogenic amine contents varied according to the processing method but remained lower than levels considered hazardous for human health. The major fatty acids present in adjuevan from method 1 were docosahexaenoic acid, palmitic acid, and oleic acid. In adjuevan from method 2, the major fatty acids were oleic acid, stearic acid, and palmitic acid. The omega (w)-3/w-6 ratio was 8.87 and 4.12 for adjuevan from methods 1 and 2, respectively. Most of the fatty acids are considered healthy fats, making adjuevan a useful food for treating and preventing lifestyle diseases. The volatile compounds found composed of 19 aldehydes, 12 alcohols, 7 esters, 7 ketones, 3 furans, 10 aromatic compounds, and 7 acids with aldehyde, alcohol, and ester compounds as the predominant groups. Among the aldehydes, 2,4-heptadienal (E,Z), octanal, and 2-octenal (E) were most prevalent in adjuevan from method 1, whereas 2-nonenal (E), 2,4-heptadienal (E,Z), and octanal were most prevalent in adjuevan from method 2.

8.
J Sci Food Agric ; 99(14): 6307-6314, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31260113

RESUMO

BACKGROUND: Pulque bread is a traditional Mexican product obtained by fermentation using microflora present only in pulque. In this study, the possibility of creating a pulque microbial consortium under laboratory conditions and its applications were evaluated. A laboratory-made consortium was compared with a consortium originating in Mexico in bread and pulque production. They were tested in various growth medium systems: pulque made from agave sap and malt extract, Mexican wheat and rye pulque bread, and European wheat and rye bread. RESULTS: Depending on the growth medium, consortiums showed differing influence on many factors, such as specific volume, weight loss after baking, soluble proteins, and crust and crumb color. Indigenous starters increased sensorial acceptance of pulque and Mexican rye bread, decreased pH, and increased titratable acidity of the breads at the highest level whereas laboratory consortia improved sensory acceptance of wheat breads. The laboratory-prepared starter in some cases improved antiradical activity. All pulques received similar consumer evaluations. However, malt pulque was the least appreciated beverage. CONCLUSION: The results show the possibility of creating a pulque microbial consortium under laboratory conditions. Depending on the flour type and the breadmaking technique, the use of a particular microbial consortium allowed modification of certain physicochemical parameters. In conclusion, it is feasible to modify bread parameters to obtain features corresponding to consumer demands by using an appropriate microflora, pulque, or flour type. Moreover, this research describes, for the first time, the use of rye malt for pulque and rye flour for pulque bread preparation as raw materials. © 2019 Society of Chemical Industry.


Assuntos
Bactérias/metabolismo , Pão/microbiologia , Consórcios Microbianos , Agave/metabolismo , Agave/microbiologia , Bactérias/classificação , Bactérias/genética , Bactérias/isolamento & purificação , Pão/análise , Fermentação , Farinha/análise , Farinha/microbiologia , Manipulação de Alimentos , Humanos , México , Secale/metabolismo , Secale/microbiologia , Paladar , Triticum/metabolismo , Triticum/microbiologia
9.
Food Res Int ; 119: 477-491, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30884680

RESUMO

Cocoa quality depends on several parameters, such as cocoa variety, environmental growth conditions, cultivation technique, and post-harvest treatments applied to coca beans. In this work, we studied the impact of cocoa post-harvest processing on both microbial communities structure and volatile composition. Cocoa beans samples were fermented in wooden boxes in Ivory Coast at different time intervals with turning and without turning, and derived from pods stored for two different duration times. Cocoa beans were analyzed using a molecular fingerprinting method (PCR-DGGE) in order to detect variations in microbial communities' structure; this global analysis was coupled to SPME-GC-MS for assessing cocoa volatile profiles. The results showed that the main parameter that influenced microbial communities structure was fermentation time, followed by turning, whereas, pods storage duration had a minor impact. Similar results were obtained for aromatic profile, except for pods storage duration that significantly affected volatile compound production. Global statistical analysis using Canonical Correspondence Analysis (CCA), showed the relationship between microbial communities and volatile composition. Furthermore, this study allowed the identification of discriminating microbial and chemical markers of cocoa post-harvest processing.


Assuntos
Cacau/química , Cacau/microbiologia , Fermentação , Armazenamento de Alimentos/métodos , Microbiota , Compostos Orgânicos Voláteis/isolamento & purificação , Bactérias/genética , Bactérias/isolamento & purificação , Chocolate/análise , Manipulação de Alimentos/métodos , Microbiologia de Alimentos , Fungos/genética , Fungos/isolamento & purificação , Cromatografia Gasosa-Espectrometria de Massas , Microbiota/genética , Fatores de Tempo
10.
J Basic Microbiol ; 59(2): 158-165, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30240041

RESUMO

Ochratoxin A (OTA) is a nephrotoxic, teratogenic, immunotoxic, and carcinogenic mycotoxin which is produced in tropical zones mainly by Aspergillus carbonarius, A. niger, A. ochraceus, and A. westerdijkiae. A. ochraceus and A. westerdijkiae species are phenotypically and genomically very close but A. westerdijkiae produce OTA at a very higher level than A. ochraceus. These species have been differentiated recently. The DNA primer pairs which were drawn so far are not specific and a genomic region of the same size is amplified for both species or they are too specific, and in this case, the DNA of a single species is amplified. To help preventing OTA contamination of foodstuffs, the PCR-DGGE (Denaturing Gradient Gel Electrophoresis) method was used to discriminate between A. ochraceus and A. westerdijkiae DNA fragments of the same size but with different sequences and thus faster access to a diagnosis of the toxigenic potential of the fungal microflora. The proposed methodology was able to differentiate A. westerdijkiae from A. ochraceus with only one primer pairs in a single run. A calibration based on initial DNA content was obtained from image analysis of the DGGE gels and a method of quantification of the two strains was proposed.


Assuntos
Aspergillus ochraceus/genética , Aspergillus ochraceus/metabolismo , Aspergillus/genética , Aspergillus/metabolismo , Eletroforese em Gel de Gradiente Desnaturante/métodos , Ocratoxinas/biossíntese , Reação em Cadeia da Polimerase/métodos , Primers do DNA , DNA Fúngico/análise , Fungos/genética , Genes Fúngicos/genética , Microbiota/genética , Micotoxinas/genética , Ocratoxinas/análise , Sensibilidade e Especificidade , Alinhamento de Sequência , Análise de Sequência de DNA
11.
AIMS Microbiol ; 4(2): 347-361, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-31294220

RESUMO

The prevalence of diarrheal diseases in children aged from 6 to 24 months in Burkina Faso is 38%. These diarrheas may be due to the consumption of contaminated weaning food. Therefore, the microbiological quality of follow up infant flours used as supplement foods is a key-point to reduce children diseases. In this study, the microbiological safety of locally-produced infant flours was investigated. One hundred and ninety-nine (199) samples were collected mainly in retails outlets and in Recovery and Nutrition Education Centers. According to the Burkina Faso regulations, microbiological analyses were carried out for Total Aerobic Mesophilic Flora (TAMF), thermotolerant coliforms, Salmonella spp. and yeasts/molds. The bacterial and fungal isolates were identified using phenotypic and genotypic methods and the study of the production of mycotoxins was carried out from the fungal isolates. In collected samples, the TAMF count ranged from 0 to 1.8 × 106 CFU/g with a total average of 6.3 × 104 CFU/g. About 2% of the samples had a microbial load exceeding the standards (105 CFU/g). No Salmonella spp. was isolated in the final infant flours. However, the presence of Enterobacteriaceae (Klebsiella spp. Enterobacter spp. and Cronobacter spp.) was detected and molecular characterization revealed also the presence of fungal species of the genus Aspergillus spp., Penicillium spp. and Fusarium spp. Some of these species were found to produce aflatoxins, ochratoxin A and fumonisins, which are potential carcinogenic toxins. These results demonstrated the need for a preventive approach based on the application of Hazard Analysis Critical Control Point in the food industry to ensure food safety of infant flours in Burkina Faso.

12.
Toxins (Basel) ; 9(11)2017 10 31.
Artigo em Inglês | MEDLINE | ID: mdl-29088078

RESUMO

Several strains of a new aflatoxigenic species of Aspergillus, A. korhogoensis, were isolated in the course of a screening study involving species from section Flavi found contaminating peanuts (Arachis hypogaea) and peanut paste in the Côte d'Ivoire. Based on examination of four isolates, this new species is described using a polyphasic approach. A concatenated alignment comprised of nine genes (ITS, benA, cmdA, mcm7, amdS, rpb1, preB, ppgA, and preA) was subjected to phylogenetic analysis, and resulted in all four strains being inferred as a distinct clade. Characterization of mating type for each strain revealed A. korhogoensis as a heterothallic species, since three isolates exhibited a singular MAT1-1 locus and one isolate exhibited a singular MAT1-2 locus. Morphological and physiological characterizations were also performed based on their growth on various types of media. Their respective extrolite profiles were characterized using LC/HRMS, and showed that this new species is capable of producing B- and G-aflatoxins, aspergillic acid, cyclopiazonic acid, aflavarins, and asparasones, as well as other metabolites. Altogether, our results confirm the monophyly of A. korhogoensis, and strengthen its position in the A. flavus clade, as the sister taxon of A. parvisclerotigenus.


Assuntos
Aflatoxinas/metabolismo , Aspergillus , Sequência de Aminoácidos , Arachis/microbiologia , Aspergillus/citologia , Aspergillus/genética , Aspergillus/isolamento & purificação , Aspergillus/metabolismo , Côte d'Ivoire , Contaminação de Alimentos/análise , Genes Fúngicos , Filogenia , Metabolismo Secundário
13.
Fungal Biol ; 120(5): 745-51, 2016 05.
Artigo em Inglês | MEDLINE | ID: mdl-27109370

RESUMO

The effects of light at different wavelengths and photoperiod on growth and ochratoxin A production of Aspergillus carbonarius and Aspergillus westerdijkiae were studied: far-red (740 nm), red (625 nm), blue (445 nm), and UV-A (366 nm). Fungal growth was not significantly affected by photoperiod or light wavelength; the only exception was A. westerdijkiae which showed reduced growth under UV-A light (366 nm). Short-wavelength blue light (445 nm) and UV-A light caused a reduction in ochratoxin A production of both fungal species. However, long-wavelength red light (625 nm) and far-red light (740 nm) reduced ochratoxin A production only in A. westerdijkiae but not in A. carbonarius. It is believed that this difference in reactivity to light is due to differences in the melanin content of the two fungal species: A. carbonarius is a black fungus with higher melanin content than A. westerdijkiae, a yellow fungus. Other possible explanations for the reduction of ochratoxin A production by light were also discussed.


Assuntos
Aspergillus/crescimento & desenvolvimento , Aspergillus/efeitos da radiação , Luz , Ocratoxinas/metabolismo , Raios Ultravioleta , Aspergillus/metabolismo
14.
Artigo em Inglês | MEDLINE | ID: mdl-26560552

RESUMO

Cocoa beans are the principal raw material for chocolate manufacture. Moulds have an important place in the change in the quality of cocoa beans due to their role in the production of free fatty acids and mycotoxins, namely ochratoxin A (OTA). This study investigated the impact of the key post-harvest treatments, namely the fermentation and drying methods on OTA contamination of raw cocoa beans. Analytical methods for OTA detection were based on solid-liquid extraction, clean-up using an immunoaffinity column, and identification by reversed-phase HPLC with fluorescence detection. Of a total of 104 randomly selected cocoa samples analysed, 32% had OTA contents above 2 µg kg(-1). Cocoa sourced from pods in a bad state of health had a maximum OTA content of 39.2 µg kg(-1), while that obtained from healthy pods recorded 11.2 µg kg(-1). The production of OTA in cocoa beans increased according to the pod-opening delay and reached 39.2 µg kg(-1) after an opening delay of 7 days after harvest, while 6.1 and 11.2 µg kg(-1) were observed when pods were opened after 0 and 4 days. OTA production also seemed to depend considerably to the cocoa fermentation materials. When using plastic boxes for bean fermentation, the OTA production was enhanced and reached an average OTA content of about 4.9 µg kg(-1), while the raw cocoa treated in banana leaves and wooden boxes recorded 1.6 and 2.2 µg kg(-1) on average respectively. In parallel, the OTA production was not really influenced by either the mixing or the duration of the fermentation or the drying materials.


Assuntos
Cacau/química , Contaminação de Alimentos/análise , Manipulação de Alimentos , Ocratoxinas/análise
15.
Crit Rev Food Sci Nutr ; 56(2): 306-17, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-24834835

RESUMO

Traceability of seafood is a much needed service for the seafood industry. Current ways of tracing seafood are minimal while tracing of shellfish is nearly nonexistent. Tracing fish and shellfish are necessary for indicating where the fish and shellfish were fished from, farmed and packed from. This study reviews history of traceability of aquaculture and analytical approaches to verify the origin of seafood. It then describes the new molecular technique of the traceability by using PCR-DGGE to discriminate the geographical origin of fish (cases studies of Pangasius fish from Viet Nam and Sea bass fish from France) by analysis the DNA fragments of microorganisms (bacteria) on fish. This method is based on the assumption that the microbial communities of food are specific to a geographic area.


Assuntos
Peixes/genética , Análise de Alimentos/métodos , Alimentos Marinhos/análise , Frutos do Mar/análise , Animais , Bactérias/genética , Peixes/microbiologia
16.
J Pathog ; 2012: 605037, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22577561
17.
J Pathog ; 2011: 429069, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-22567333

RESUMO

Although Yersinia enterocolitica is usually transmitted through contaminated food and untreated water, occasional transmission such as human-to-human, animal-to-human and blood transfusion associated transmission have also identified in human disease. Of the six Y. enterocolitica biotypes, the virulence of the pathogenic biotypes, namely, 1B and 2-5 is attributed to the presence of a highly conserved 70-kb virulence plasmid, termed pYV/pCD and certain chromosomal genes. Some biotype 1A strains, despite lacking virulence plasmid (pYV) and traditional chromosomal virulence genes, are isolated frequently from humans with gastrointestinal diseases similar to that produced by isolates belonging known pathogenic biotypes. Y. enterocolitica pathogenic biotypes have evolved two major properties: the ability to penetrate the intestinal wall, which is thought to be controlled by plasmid genes, and the production of heat-stable enterotoxin, which is controlled by chromosomal genes.

18.
J Food Prot ; 73(12): 2225-31, 2010 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-21219740

RESUMO

A group of 291 Staphylococcus aureus isolates from mastitic cow's milk (n = 125), bulk tank milk (n = 96), and Minas frescal cheese (n = 70) were screened for staphylococcal enterotoxin (SE) genes (sea, seb, sec, sed, see, seg, seh, sei, selj, and sell) and for the tst-1 gene encoding staphylococcal toxic shock syndrome toxin 1 by PCR assay. A total of 109 (37.5%) of the isolates were positive for at least one of these 11 genes, and 23 distinct genotypes of toxin genes were observed. Of the S. aureus isolates bearing SE genes, 17 (13.6%) were from mastitic cow's milk, 41 (41.7%) were from bulk tank milk, and 51 (72.9%) were from Minas frescal cheese. The occurrence of exclusively more recently described SE genes (seg through sell) was considerably higher (87 of 109 PCR-positive strains) than that of classical SE genes (sea through see, 15 strains). The SE genes most commonly detected were seg and sei; they were found alone or in different combinations with other toxin genes, but in 60.8% of the cases they were codetected. No strain possessed see. The tst-1 gene was found in eight isolates but none from mastitic cow's milk. Macrorestriction analysis of chromosomal DNA from 89 S. aureus isolates positive for SE gene(s) was conducted with the enzyme SmaI. Fifty-five distinct pulsed-field gel electrophoresis patterns were found, demonstrating a lack of predominance of any specific clone. A second enzyme, Apa I, used for some isolates was less discriminating than Sma I. The high genotype diversity of potential toxigenic S. aureus strains found in this study, especially from Minas frescal cheese, suggests various sources of contamination. Efforts from the entire production chain are required to improve consumer safety.


Assuntos
Queijo/microbiologia , Enterotoxinas/genética , Contaminação de Alimentos/análise , Leite/microbiologia , Staphylococcus aureus/isolamento & purificação , Animais , Brasil , Bovinos , Qualidade de Produtos para o Consumidor , DNA Bacteriano/análise , Enterotoxinas/biossíntese , Feminino , Contaminação de Alimentos/prevenção & controle , Microbiologia de Alimentos , Genótipo , Humanos , Mastite Bovina/microbiologia , Reação em Cadeia da Polimerase , Intoxicação Alimentar Estafilocócica/prevenção & controle , Infecções Estafilocócicas/microbiologia , Infecções Estafilocócicas/veterinária , Staphylococcus aureus/patogenicidade
19.
Yeast ; 26(10): 567-73, 2009 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-19784935

RESUMO

The determination of geographical origin is a demand of the traceability system of import-export food products. One hypothesis for tracing the source of a product is by global analysis of the microbial communities of the food and statistical linkage of this analysis to the geographical origin of the food. For this purpose, a molecular technique employing 26S rDNA profiles generated by PCR-DGGE was used to detect the variation in yeast community structures of three species of Physalis fruit (Physalis ixocarpa Brat, Physalis pubescens L, Physalis pruinosa L) from four Egyptian regions (Qalyoubia, Minufiya, Beheira and Alexandria Governments). When the 26S rDNA profiles were analysed by multivariate analysis, distinct microbial communities were detected. The band profiles of Physalis yeasts from different Governments were specific for each location and could be used as a bar code to discriminate the origin of the fruits. This method is a new traceability tool which provides fruit products with a unique biological bar code and makes it possible to trace back the fruits to their original location.


Assuntos
Impressões Digitais de DNA/métodos , DNA Fúngico/genética , DNA Ribossômico/genética , Physalis/microbiologia , Reação em Cadeia da Polimerase/métodos , Leveduras/classificação , Leveduras/genética , Egito , Eletroforese em Gel de Poliacrilamida/métodos , Frutas/microbiologia , Geografia , Desnaturação de Ácido Nucleico , RNA Ribossômico/genética , Sensibilidade e Especificidade , Leveduras/isolamento & purificação
20.
J Agric Food Chem ; 56(13): 4976-81, 2008 Jul 09.
Artigo em Inglês | MEDLINE | ID: mdl-18540613

RESUMO

Kava ( Piper methysticum Forst f., Piperaceae) has anxiolytic properties and the ability to promote a state of relaxation without the loss of mental alertness. The rapid growth of the nutraceutical market between 1998 and 2000 has been stopped by a ban in Europe and Australia because of some suspicion of liver toxicity. It is now important to develop a fast, cheap, and reliable quality test to control kava exports. The aim of this study is to develop a calibration of the near-infrared reflectance spectroscopy (NIRS) using partial least-squares (PLS) regression. Two hundred thirty-six samples of kava roots, stumps, and basal stems were collected from the Vanuatu Agricultural Research and Technical Centre germplasm collection and from four villages. These samples, representing 45 different varieties, were analyzed using NIRS to record their absorption spectra between 400 and 2500 nm. A set of 101 selected samples was analyzed for their kavalactone content using HPLC. The results were used for PLS calibration of the NIRS. The NIRS prediction of the kavalactone content and the dry matter were in agreement with the HPLC results. There were good correlations between these two series of results, and coefficients ( R (2)) were all close to 1. The measurements were reproducible and had repeatability on par with the HPLC method. The NIRS system has been calibrated for the six major kavalactone content measurements, and it is suggested that this method could be used for quality control in Vanuatu.


Assuntos
Suplementos Nutricionais/normas , Kava/química , Lactonas/análise , Espectroscopia de Luz Próxima ao Infravermelho/normas , Calibragem , Qualidade de Produtos para o Consumidor/normas , Suplementos Nutricionais/análise , Estruturas Vegetais/química , Controle de Qualidade , Vanuatu
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