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1.
Poult Sci ; 103(2): 103319, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38141274

RESUMO

Poultry meat is a highly esteemed product among consumers. However, the emphasis on increasing body weight has led to a rise in the proportion of rapidly shrinking fibers, adversely affecting the quality and shelf life of poultry meat. With a growing awareness of dietetics among consumers, there is an increasing challenge to produce chicken meat that is not only free of antibiotics but also beneficial for dietary and health reasons. Biogenic amines (BA) can serve as indicators of meat freshness and quality. While they play vital roles in the body, excessive consumption of BA can have toxic and carcinogenic effects. The objective of this study was to examine the impact of supplementing feed with garlic extract and ß-alanine (ß-Ala) on the formation of BA and amino acid (AA) levels in the breast and leg muscles of chickens stored under aerobic chilling conditions. The muscles were obtained from chickens fed with garlic extract and ß-Ala in quantities of 0.5 and 2% for each additive, as well as 0.5 and 2% of their combination. Analyses were conducted on d 1, 3, 5, 7, and 10 of storage. ß-Ala supplementation increased the proportion of this AA in breast (P < 0.01) and leg muscles (P < 0.01), along with a rise in the proportion of nonessential AA (NEAA; sum of aspartic, aspartic acid, glutamic, glutamic acid, serine, ß-Ala, and proline) (P < 0.01). The levels of BA changed during storage in breast and leg muscles (P < 0.001). The applied diet significantly influenced the formation of putrescine (P = 0.030), phenylethylamine (P = 0.003), agmatine (P = 0.025), and total BA (P < 0.001) in breast muscles. On the 10 d of storage, the breast muscles exhibited the lowest BA index (BAI) in the group, with a diet supplemented with 0.5% garlic extract and 0.5% ß-Ala (P < 0.05). The leg muscles showed a similar BA trend as the breast muscles. These supplements may be utilized in production to augment the protein content of chicken muscles and potentially decrease the BAI index during meat storage.


Assuntos
Aminoácidos , Alho , Animais , Galinhas/fisiologia , Suplementos Nutricionais/análise , Dieta/veterinária , Antioxidantes , Aminas Biogênicas , beta-Alanina , Carne/análise , Extratos Vegetais , Ração Animal/análise
2.
Crit Rev Food Sci Nutr ; : 1-26, 2023 Sep 19.
Artigo em Inglês | MEDLINE | ID: mdl-37724793

RESUMO

Fermented food has unique properties and high nutritional value, and thus, should constitute a basic element of a balanced and health-promoting diet. However, it can accumulate considerable amount of biogenic amines (BAs), which ingested in excess can lead to adverse health effects. The application of plant-derived additives represents a promising strategy to ensure safety or enhance the functional and organoleptic properties of fermented food. This review summarizes currently available data on the application of plant-origin additives with the aim to reduce BA content in fermented products. The importance of ensuring fermented food safety has been highlighted considering the growing evidence of beneficial effects resulting from the consumption of this type of food, as well as the increasing number of individuals sensitive to BAs. The examined plant-origin additives reduced the BA concentration to varying degrees, and their efficacy depended on the type of additive, matrix, autochthonous, and inoculated microorganisms, as well as the manufacturing conditions. The main mechanisms of action include antimicrobial effects and the inhibition of microbial decarboxylases. Further research on the optimization of bioactive substances extraction, standardization of their chemical composition, and development of detailed procedures for its use in fermented products manufacturing are needed.

3.
Int J Mol Sci ; 24(12)2023 Jun 14.
Artigo em Inglês | MEDLINE | ID: mdl-37373290

RESUMO

Due to irrational antibiotic stewardship, an increase in the incidence of multidrug resistance of bacteria has been observed recently. Therefore, the search for new therapeutic methods for pathogen infection treatment seems to be necessary. One of the possibilities is the utilization of bacteriophages (phages)-the natural enemies of bacteria. Thus, this study is aimed at the genomic and functional characterization of two newly isolated phages targeting MDR Salmonella enterica strains and their efficacy in salmonellosis biocontrol in raw carrot-apple juice. The Salmonella phage vB_Sen-IAFB3829 (Salmonella phage strain KKP 3829) and Salmonella phage vB_Sen-IAFB3830 (Salmonella phage strain KKP 3830) were isolated against S. I (6,8:l,-:1,7) strain KKP 1762 and S. Typhimurium strain KKP 3080 host strains, respectively. Based on the transmission electron microscopy (TEM) and whole-genome sequencing (WGS) analyses, the viruses were identified as members of tailed bacteriophages from the Caudoviricetes class. Genome sequencing revealed that these phages have linear double-stranded DNA and sizes of 58,992 bp (vB_Sen-IAFB3829) and 50,514 bp (vB_Sen-IAFB3830). Phages retained their activity in a wide range of temperatures (from -20 °C to 60 °C) and active acidity values (pH from 3 to 11). The exposure of phages to UV radiation significantly decreased their activity in proportion to the exposure time. The application of phages to the food matrices significantly reduced the level of Salmonella contamination compared to the control. Genome analysis showed that both phages do not encode virulence or toxin genes and can be classified as virulent bacteriophages. Virulent characteristics and no possible pathogen factors make examined phages feasible to be potential candidates for food biocontrol.


Assuntos
Bacteriófagos , Fagos de Salmonella , Salmonella enterica , Salmonella/genética , Bacteriófagos/genética , Fagos de Salmonella/genética , Salmonella enterica/genética , Genômica , Genoma Viral
4.
Genes (Basel) ; 14(6)2023 06 20.
Artigo em Inglês | MEDLINE | ID: mdl-37372483

RESUMO

The spoilage of juices by Alicyclobacillus spp. remains a serious problem in industry and leads to economic losses. Compounds such as guaiacol and halophenols, which are produced by Alicyclobacillus, create undesirable flavors and odors and, thus, decrease the quality of juices. The inactivation of Alicyclobacillus spp. constitutes a challenge because it is resistant to environmental factors, such as high temperatures, and active acidity. However, the use of bacteriophages seems to be a promising approach. In this study, we aimed to isolate and comprehensively characterize a novel bacteriophage targeting Alicyclobacillus spp. The Alicyclobacillus phage strain KKP 3916 was isolated from orchard soil against the Alicyclobacillus acidoterrestris strain KKP 3133. The bacterial host's range and the effect of phage addition at different rates of multiplicity of infections (MOIs) on the host's growth kinetics were determined using a Bioscreen C Pro growth analyzer. The Alicyclobacillus phage strain KKP 3916, retained its activity in a wide range of temperatures (from 4 °C to 30 °C) and active acidity values (pH from 3 to 11). At 70 °C, the activity of the phage decreased by 99.9%. In turn, at 80 °C, no activity against the bacterial host was observed. Thirty minutes of exposure to UV reduced the activity of the phages by almost 99.99%. Based on transmission-electron microscopy (TEM) and whole-genome sequencing (WGS) analyses, the Alicyclobacillus phage strain KKP 3916 was classified as a tailed bacteriophage. The genomic sequencing revealed that the newly isolated phage had linear double-stranded DNA (dsDNA) with sizes of 120 bp and 131 bp and 40.3% G+C content. Of the 204 predicted proteins, 134 were of unknown function, while the remainder were annotated as structural, replication, and lysis proteins. No genes associated with antibiotic resistance were found in the genome of the newly isolated phage. However, several regions, including four associated with integration into the bacterial host genome and excisionase, were identified, which indicates the temperate (lysogenic) life cycle of the bacteriophage. Due to the risk of its potential involvement in horizontal gene transfer, this phage is not an appropriate candidate for further research on its use in food biocontrol. To the best of our knowledge, this is the first article on the isolation and whole-genome analysis of the Alicyclobacillus-specific phage.


Assuntos
Alicyclobacillus , Bacteriófagos , Alicyclobacillus/genética , Bacteriófagos/genética , Temperatura Alta , Temperatura
5.
Viruses ; 15(1)2023 Jan 06.
Artigo em Inglês | MEDLINE | ID: mdl-36680211

RESUMO

This study aimed to evaluate the effectiveness of the phage cocktail to improve the microbiological quality of five different mixed-leaf salads: rucola, mixed-leaf salad with carrot, mixed-leaf salad with beetroot, washed and unwashed spinach, during storage in refrigerated conditions. Enterobacterales rods constituted a significant group of bacteria in the tested products. Selected bacteria were tested for antibiotic resistance profiles and then used to search for specific bacteriophages. Forty-three phages targeting bacteria dominant in mixed-leaf salads were isolated from sewage. Their titer was determined, and lytic activity was assessed using the Bioscreen C Pro automated growth analyzer. Two methods of phage cocktail application including spraying, and an absorption pad were effective for rucola, mixed leaf salad with carrot, and mixed leaf salad with beetroot. The maximum reduction level after 48 h of incubation reached 99.9% compared to the control sample. In washed and unwashed spinach, attempts to reduce the number of microorganisms did not bring the desired effect. The decrease in bacteria count in the lettuce mixes depended on the composition of the autochthonous saprophytic bacteria species. Both phage cocktail application methods effectively improved the microbiological quality of minimally processed products. Whole-spectral phage cocktail application may constitute an alternative food microbiological quality improvement method without affecting food properties.


Assuntos
Bacteriófagos , Bactérias , Carga Bacteriana
6.
Pathogens ; 11(11)2022 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-36365074

RESUMO

Salmonella is one of the most important foodborne pathogens. Fifty-three strains of Salmonella deposited in the Culture Collection of Industrial Microorganisms-Microbiological Resources Center (IAFB) were identified using molecular and proteomic analyses. Moreover, the genetic similarity of the tested strains was determined using the PFGE method. Main virulence genes were identified, and phenotypical antibiotic susceptibility profiles and prevalence of resistance genes were analyzed. Subsequently, the occurrence of the main mechanisms of ß-lactam resistance was determined. Virulence genes, invA, fimA, and stn were identified in all tested strains. Phenotypic tests, including 28 antibiotics, showed that 50.9% of the strains were MDR. The tet genes associated with tetracyclines resistance were the most frequently identified genes. Concerning the genes associated with ESBL-producing Salmonella, no resistance to the TEM and CTX-M type was identified, and only two strains (KKP 1597 and KKP 1610) showed resistance to SHV. No strains exhibited AmpC-type resistance but for six Salmonella strains, the efflux-related resistance of PSE-1 was presented. The high number of resistant strains in combination with multiple ARGs in Salmonella indicates the possible overuse of antibiotics. Our results showed that it is necessary to monitor antimicrobial resistance profiles in all food chain links constantly and to implement a policy of proper antibiotic stewardship to contain or at least significantly limit the further acquisition of antibiotic resistance among Salmonella strains.

7.
Sci Rep ; 12(1): 20063, 2022 11 21.
Artigo em Inglês | MEDLINE | ID: mdl-36414746

RESUMO

Fermentation of two red beet cultivars (Wodan and Alto) with single-strain starter cultures consisting of selected strains of lactic acid bacteria (LAB) of plant origin (Weissella cibaria KKP2058, Levilactobacillus brevis ZF165) and a multi-strain culture (containing W. cibaria KKP2058, L. brevis ZF165, Lactiplantibacillus plantarum KKP1822, Limosilactobacillus fermentum KKP1820, and Leuconostoc mesenteroides JEIIF) was performed to evaluate their impact on betalains, free amino acids, formation of biogenic amines, and antioxidative properties of the juice formed. Next-generation sequencing data analysis used to identify the microbial community revealed that the starter cultures promoted the dominance of the genus Lactobacillus, and decreased the proportion of spoilage bacteria compared to spontaneously fermented juices. Generally, the fermentation process significantly influenced the amount of the analyzed compounds, leading in most cases to their reduction. The observed changes in the studied parameters depended on the starter culture used, indicating different metabolic activities of the LAB strains towards bioactive compounds. The use of multi-strain starter cultures allowed to largely prevent the reduction of betacyanins and histamine formation.


Assuntos
Antioxidantes , Lactobacillales , Antioxidantes/metabolismo , Aminoácidos/metabolismo , Microbiologia de Alimentos , Polônia , Aminas Biogênicas/metabolismo , Lactobacillales/genética , Lactobacillales/metabolismo
8.
Viruses ; 15(1)2022 12 20.
Artigo em Inglês | MEDLINE | ID: mdl-36680050

RESUMO

The aim of this study was to isolate phage enzymes and apply them in vitro for eradication of the dominant saprophytic bacteria isolated from minimally processed food. Four bacteriophages-two Enterobacter-specific and two Serratia-specific, which produce lytic enzymes-were used in this research. Two methods of phage enzyme isolation were tested, namely precipitation with acetone and ultracentrifugation. It was found that the number of virions could be increased almost 100 times due to the extension of the cultivation time (72 h). The amplification of phage particles and lytic proteins was dependent on the time of cultivation. Considering the influence of isolated enzymes on the growth kinetics of bacterial hosts, proteins isolated with acetone after 72-hour phage propagation exhibited the highest inhibitory effect. The reduction of bacteria count was dependent on the concentration of enzymes in the lysates. The obtained results indicate that phages and their lytic enzymes could be used in further research aiming at the improvement of microbiological quality and safety of minimally processed food products.


Assuntos
Bacteriófagos , Acetona , Bactérias , Carga Bacteriana , Microbiologia de Alimentos
9.
Food Microbiol ; 102: 103920, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-34809946

RESUMO

The aim of this study was to determine the biogenic amines (BAs) formed in chicken breast meat packaged using different techniques (AP, Hi-O2-MAP or VP) during the storage under different conditions (cold room or display case), to correlate the microbiological quality (TPC, LAB, Pseudomonas spp. and Enterobacteriaceae) of chicken meat with BAs formation and to assess the suitability of selected biogenic amines as indicators of chicken meat spoilage. The initial TPC of chicken fillets was 2.57-3.04 log cfu/g. Over time a systematic significant (p ≤ 0.05) increase in TPC was observed to >7.5 log cfu/g (AP and VP; display case) determined on day 9. It was found that cadaverine and tyramine dominated in quantitative terms in chicken fillets, regardless of packaging technique and storage conditions (166.00 mg/kg in AP meat in cold room on day 9 and 175.03 mg/kg on day 9 in MAP meat in display case, respectively). Taking into account the BAI, high and significant (p ≤ 0.05) correlation coefficients (from 0.51 to 0.95) were obtained with all analyzed indicators of microbiological quality. The concentration of cadaverine, putrescine contents or BAI can potentially serve as chemical quality indicator for freshness of chicken meat.


Assuntos
Aminas Biogênicas , Embalagem de Alimentos , Aves Domésticas/microbiologia , Animais , Aminas Biogênicas/análise , Cadaverina/análise , Galinhas , Microbiologia de Alimentos , Conservação de Alimentos , Carne/análise , Tiramina/análise
10.
Acta Sci Pol Technol Aliment ; 20(4): 473-484, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34724371

RESUMO

BACKGROUND: ood producers strive to meet the changing needs of consumers while maintaining the highest nutritional value of the products they supply. Physicochemical methods, which include modified atmosphere packaging, membrane techniques or ultrasounds, are the most frequently used to preserve food. Alternatively, biological methods can be applied, one of which is the use of bacteriophages (phages) to limit bacterial growth in the food environment. The purpose of our research was to verify the possibility of the use of bacteriophages as an antibacterial agent in minimally processed food environments of vegetable origin. The first stage of the research involved the isolation of phages against the dominant bacterial microflora in the analyzed products: broccoli sprouts, spinach leaves and freshly squeezed carrot-celery juice. Bacteriophages were isolated from municipal waste collected from sewage-treatment plants. Specific bacteriophages were isolated for twenty-nine out of thirty identified bacterial strains. The lytic activity of the phages was tested using a Bioscreen C automatic growth analyzer. Three methods for applying the phage cocktail were tested: direct addition of the cocktail, spraying it on, and placing the food product on a pad soaked with the phage mixture. The food products were packaged in a protective atmosphere and stored at 20°C. The total number of bacteria after adding the phage cocktail to the products was determined during the subsequent hours of incubation using classical microbial culturing. A significant decrease in the total number of bacteria was observed in the products containing phage suspensions. The obtained results suggest that application of the phage cocktail offers the possibility to extend the shelf life of the analyzed minimally processed food products by reducing the total number of saprophytic. METHODS: , food producers strive to meet the changing needs of consumers while maintaining the highest nutritional value of the products they supply. Physicochemical methods, which include modified atmosphere packaging, membrane techniques or ultrasounds, are the most frequently used to preserve food. Alternatively, biological methods can be applied, one of which is the use of bacteriophages (phages) to limit bacterial growth in the food environment. The purpose of our research was to verify the possibility of the use of bacteriophages as an antibacterial agent in minimally processed food environments of vegetable origin. The first stage of the research involved the isolation of phages against the dominant bacterial microflora in the analyzed products: broccoli sprouts, spinach leaves and freshly squeezed carrot-celery juice. Bacteriophages were isolated from municipal waste collected from sewage-treatment plants. Specific bacteriophages were isolated for twenty-nine out of thirty identified bacterial strains. The lytic activity of the phages was tested using a Bioscreen C automatic growth analyzer. Three methods for applying the phage cocktail were tested: direct addition of the cocktail, spraying it on, and placing the food product on a pad soaked with the phage mixture. The food products were packaged in a protective atmosphere and stored at 20°C. The total number of bacteria after adding the phage cocktail to the products was determined during the subsequent hours of incubation using classical microbial culturing. A significant decrease in the total number of bacteria was observed in the products containing phage suspensions. The obtained results suggest that application of the phage cocktail offers the possibility to extend the shelf life of the analyzed minimally processed food products by reducing the total number of saprophytic bac. RESULTS: , food producers strive to meet the changing needs of consumers while maintaining the highest nutritional value of the products they supply. Physicochemical methods, which include modified atmosphere packaging, membrane techniques or ultrasounds, are the most frequently used to preserve food. Alternatively, biological methods can be applied, one of which is the use of bacteriophages (phages) to limit bacterial growth in the food environment. The purpose of our research was to verify the possibility of the use of bacteriophages as an antibacterial agent in minimally processed food environments of vegetable origin. The first stage of the research involved the isolation of phages against the dominant bacterial microflora in the analyzed products: broccoli sprouts, spinach leaves and freshly squeezed carrot-celery juice. Bacteriophages were isolated from municipal waste collected from sewage-treatment plants. Specific bacteriophages were isolated for twenty-nine out of thirty identified bacterial strains. The lytic activity of the phages was tested using a Bioscreen C automatic growth analyzer. Three methods for applying the phage cocktail were tested: direct addition of the cocktail, spraying it on, and placing the food product on a pad soaked with the phage mixture. The food products were packaged in a protective atmosphere and stored at 20°C. The total number of bacteria after adding the phage cocktail to the products was determined during the subsequent hours of incubation using classical microbial culturing. A significant decrease in the total number of bacteria was observed in the products containing phage suspensions. The obtained results suggest that application of the phage cocktail offers the possibility to extend the shelf life of the analyzed minimally processed food products by reducing the total number of saprophytic bacteria.


Assuntos
Bacteriófagos , Bactérias , Verduras
11.
Int J Mol Sci ; 22(22)2021 Nov 18.
Artigo em Inglês | MEDLINE | ID: mdl-34830335

RESUMO

The food industry is still searching for novel solutions to effectively ensure the microbiological safety of food, especially fresh and minimally processed food products. Nowadays, the use of bacteriophages as potential biological control agents in microbiological food safety and preservation is a promising strategy. The aim of the study was the isolation and comprehensive characterization of novel bacteriophages with lytic activity against saprophytic bacterial microflora of minimally processed plant-based food products, such as mixed leaf salads. From 43 phages isolated from municipal sewage, four phages, namely Enterobacter phage KKP 3263, Citrobacter phage KKP 3664, Enterobacter phage KKP 3262, and Serratia phage KKP 3264 have lytic activity against Enterobacter ludwigii KKP 3083, Citrobacter freundii KKP 3655, Enterobacter cloacae KKP 3082, and Serratia fonticola KKP 3084 bacterial strains, respectively. Transmission electron microscopy (TEM) and whole-genome sequencing (WGS) identified Enterobacter phage KKP 3263 as an Autographiviridae, and Citrobacter phage KKP 3664, Enterobacter phage KKP 3262, and Serratia phage KKP 3264 as members of the Myoviridae family. Genome sequencing revealed that these phages have linear double-stranded DNA (dsDNA) with sizes of 39,418 bp (KKP 3263), 61,608 bp (KKP 3664), 84,075 bp (KKP 3262), and 148,182 bp (KKP 3264). No antibiotic resistance genes, virulence factors, integrase, recombinase, or repressors, which are the main markers of lysogenic viruses, were annotated in phage genomes. Serratia phage KKP 3264 showed the greatest growth inhibition of Serratia fonticola KKP 3084 strain. The use of MOI 1.0 caused an almost 5-fold decrease in the value of the specific growth rate coefficient. The phages retained their lytic activity in a wide range of temperatures (from -20 °C to 50 °C) and active acidity values (pH from 4 to 11). All phages retained at least 70% of lytic activity at 60 °C. At 80 °C, no lytic activity against tested bacterial strains was observed. Serratia phage KKP 3264 was the most resistant to chemical factors, by maintaining high lytic activity across a broader range of pH from 3 to 11. The results indicated that these phages could be a potential biological control agent against saprophytic bacterial microflora of minimally processed plant-based food products.


Assuntos
Bacteriófagos/genética , Citrobacter freundii/virologia , Enterobacter cloacae/virologia , Inocuidade dos Alimentos/métodos , Genoma Viral , Myoviridae/genética , Serratia/virologia , Bacteriólise/fisiologia , Bacteriófagos/classificação , Bacteriófagos/isolamento & purificação , Agentes de Controle Biológico/classificação , Agentes de Controle Biológico/isolamento & purificação , DNA Viral/genética , Microbiologia de Alimentos/métodos , Embalagem de Alimentos/métodos , Conservação de Alimentos/métodos , Humanos , Myoviridae/classificação , Myoviridae/isolamento & purificação , Filogenia , Esgotos/virologia , Verduras/microbiologia
12.
Molecules ; 26(19)2021 Sep 24.
Artigo em Inglês | MEDLINE | ID: mdl-34641340

RESUMO

Salt concentrations in brine and temperature are the major environmental factors that affect activity of microorganisms and, thus may affect formation of biogenic amines (BAs) during the fermentation process. A model system to ferment cucumbers with low salt (0.5%, 1.5% or 5.0% NaCl) at two temperatures (11 or 23 °C) was used to study the ability of indigenous microbiota to produce biogenic amines and metabolize amino acid precursors. Colony counts for presumptive Enterococcus and Enterobacteriaceae increased by 4 and up to 2 log of CFU∙mL-1, respectively, and remained viable for more than 10 days. 16S rRNA sequencing showed that Lactobacillus and Enterobacter were dominant in fermented cucumbers with 0.5% and 1.5% salt concentrations after storage. The initial content of BAs in raw material of 25.44 ± 4.03 mg∙kg-1 fluctuated throughout experiment, but after 6 months there were no significant differences between tested variants. The most abundant BA was putrescine, that reached a maximum concentration of 158.02 ± 25.11 mg∙kg-1. The Biogenic Amines Index (BAI) calculated for all samples was significantly below that needed to induce undesirable effects upon consumption. The highest value was calculated for the 23 °C/5.0% NaCl brine variant after 192 h of fermentation (223.93 ± 54.40). Results presented in this work indicate that possibilities to control spontaneous fermentation by changing salt concentration and temperature to inhibit the formation of BAs are very limited.


Assuntos
Aminoácidos/análise , Bactérias/classificação , Aminas Biogênicas/análise , Cucumis sativus/microbiologia , Metabolômica/métodos , Sais/química , Bactérias/genética , Bactérias/isolamento & purificação , Cucumis sativus/química , DNA Ribossômico/genética , Fermentação , Microbiologia de Alimentos , Conservação de Alimentos , Concentração de Íons de Hidrogênio , Filogenia , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Cloreto de Sódio/química , Temperatura
13.
Pathogens ; 10(7)2021 Jun 24.
Artigo em Inglês | MEDLINE | ID: mdl-34202800

RESUMO

The widespread use of antibiotics, especially those with a broad spectrum of activity, has resulted in the development of multidrug resistance in many strains of bacteria, including Salmonella. Salmonella is among the most prevalent causes of intoxication due to the consumption of contaminated food and water. Salmonellosis caused by this pathogen is pharmacologically treated using antibiotics such as fluoroquinolones, ceftriaxone, and azithromycin. This foodborne pathogen developed several molecular mechanisms of resistance both on the level of global and local transcription modulators. The increasing rate of antibiotic resistance in Salmonella poses a significant global concern, and an improved understanding of the multidrug resistance mechanisms in Salmonella is essential for choosing the suitable antibiotic for the treatment of infections. In this review, we summarized the current knowledge of molecular mechanisms that control gene expression related to antibiotic resistance of Salmonella strains. We characterized regulators acting as transcription activators and repressors, as well as two-component signal transduction systems. We also discuss the background of the molecular mechanisms of the resistance to metals, regulators of multidrug resistance to antibiotics, global regulators of the LysR family, as well as regulators of histone-like proteins.

14.
Environ Monit Assess ; 192(2): 142, 2020 Jan 25.
Artigo em Inglês | MEDLINE | ID: mdl-31982958

RESUMO

Both polycyclic aromatic hydrocarbons (PAHs) and legacy organochlorine insecticides (OCPs), including DDT, are dangerous chemical contaminants. The aims of this study were to (i) determine background levels of PAHs and legacy OCPs for wheat samples collected in 2017 and 2018 in Poland, (ii) identify differences between levels in wheat harvested in various regions of Poland, (iii) evaluate differences in contamination sources manifested by the profiles of the identified chemicals, (iv) identify possible correlations between different classes of chemicals present in wheat, and (v) assess the health risks associated with the presence of PAHs and OCPs in Polish wheat. Average concentrations found in the samples were 0.09 ± 0.03 µg kg-1 for benzo[a]pyrene (BaP) (formerly used as a single PAH marker), 0.43 ± 0.16 for the more recently introduced collective PAH 4 marker (benzo[a]anthracene + benzo[a]pyrene + chrysene + benzo[b]fluoranthene), and 1.07 ± 0.68 µg kg-1 for DDT and its metabolites. The PAH profiles indicated contamination from combustion-related emission sources (liquid fossil fuels, coal, biomass). Health risks associated with the presence of PAHs and OCPs in cereals were assessed using the margin of exposure (MOE) approach. The MOE values calculated based on the highest concentrations found in this study exceeded 50,000 for both BaP and PAH 4. The calculated worst-case scenario value for DDT and metabolites was as low as 0.3% of the respective tolerable daily intake (TDI) value. Assessment of dietary risk has shown that the presence of the two contaminant classes in Polish wheat grains is of low concern.


Assuntos
Praguicidas , Hidrocarbonetos Policíclicos Aromáticos , Triticum , Monitoramento Ambiental , Praguicidas/análise , Polônia , Hidrocarbonetos Policíclicos Aromáticos/análise , Triticum/química
15.
J Agric Food Chem ; 68(3): 856-868, 2020 Jan 22.
Artigo em Inglês | MEDLINE | ID: mdl-31891502

RESUMO

Biogenic amines (BAs) are low molecular weight organic bases. BAs occurring naturally in living organisms are responsible for a number of vital functions, including (in humans) secretion of gastric acids, controlling body temperature, differentiation and growth of cells, immune reactions, and brain activity. However, if oversupplied with food, BAs may cause food poisoning and produce undesirable effects. Nine BAs and eight free amino acids (FAAs) were determined in 85 samples of 19 different varieties of fermented vegetables available on the Polish retail market. Both BA and FAA levels differed significantly among various varieties of the studied fermented vegetables. Averages for the sum of all tested BAs ranged from 30.29 ± 16.43 mg·kg-1 in fermented olives to 612.1 ± 359.33 mg·kg-1 in fermented Brussels sprout. BA profiles were dominated by putrescine (42%), tyramine (20%), cadaverine (18%), and histamine (8%); jointly, the four amines amounted to 88% of all nine studied BAs. The combined level of the latter four BAs was calculated for each vegetable variety as the so-called BA index (BAI). On that basis, the risk of BA-related adverse health effects has been assessed as high/medium/low in 6/3/10 of all 19 studied varieties of fermented vegetables. Brussels sprout and broccoli turned out to be the most risky vegetables from that point of view (BAI above 400 mg·kg-1). FAA levels ranged from 54.8 ± 12.76 (fermented olives) to 3917.42 ± 1528.73 mg·kg-1 (fermented garlic). The high content of FAAs may increase the risk of forming toxic amounts of BAs, depending on characteristics of the current and added microflora as well as on environmental and technological conditions the product is subjected to.


Assuntos
Aminoácidos/análise , Aminas Biogênicas/análise , Alimentos Fermentados/análise , Verduras/química , Aminas Biogênicas/toxicidade , Brassica/química , Fermentação , Contaminação de Alimentos/análise , Fatores de Risco
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