Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 2.912
Filtrar
1.
Food Chem ; 338: 127837, 2021 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-32818863

RESUMO

Early screening of L. monocytogenes in ready-to-eat food can prevent and control its harmful effects. In this study, we propose a highly sensitive magnetic DNA sensor based on nucleic acid hybridization reaction and magnetic signal readout. We design the L. monocytogenes specific probe1 and probe2 and label them on the 30 and 250 nm magnetic nanoparticles, respectively. The hybridization reaction between the magnetic probes and DNA of L. monocytogenes could form a sandwich nanocomplex. After magnetic separation, the unbound MNP30-probe2 can act as the transverse relaxation time (T2) signal readout probe. This assay allows the one-step detection of L. monocytogenes as low as 50 CFU/mL within 2 h without DNA amplification, and the average recovery in the spiked ham sausage samples can reach 92.6%. This system integrates the high sensitivity of magnetic sensing and high efficiency of hybridization reaction, providing a promising detection platform for pathogens.


Assuntos
Microbiologia de Alimentos/métodos , Listeria monocytogenes , Produtos da Carne/microbiologia , Hibridização de Ácido Nucleico/métodos , Sondas de DNA , DNA Bacteriano , Listeria monocytogenes/genética , Fenômenos Magnéticos , Espectroscopia de Ressonância Magnética , Nanopartículas/química , Técnicas de Amplificação de Ácido Nucleico
2.
Int J Food Microbiol ; 339: 109016, 2021 Feb 02.
Artigo em Inglês | MEDLINE | ID: mdl-33360159

RESUMO

Dry-fermented sausages are prone to be colonised by Penicillium nordicum, which is one of the main ochratoxin A (OTA)-producing species. Its ability to produce this mycotoxin on dry-fermented sausages has been reported. However, the influence of the conditions of a traditional processing of a Spanish dry-fermented sausage and the intrinsic physicochemical parameters of this product such as water activity (aw) and pH on OTA production has not been studied yet. Thus, the aim of this study was to evaluate the influence of traditional processing (interaction of relative humidity (RH) x temperature x ripening days) on the evolution of pH and aw during maturation of dry-fermented sausage "salchichón" and its relationship with OTA synthesis by P. nordicum. The expression of otapks and otanps genes, both involved in the biosynthesis of the mycotoxin, was also assessed. For this, 27 raw sausages were inoculated with P. nordicum and ripened for 26 days in a drying chamber (3 days at 5 °C and 84% RH, 17 days at 12 °C and 84% RH, and 6 days at 12 °C and 80% RH). From results, although it seems that the pH slightly influenced on OTA biosynthesis, the aw had a great impact on this mycotoxin production. In fact, the two highest OTA concentrations found coincided with a dramatic rise of the aw value (0.92 aw) by day 18 of incubation when the RH of the drying chamber was still 84% and at the end of the incubation time when the aw decreased noticeably (0.87 aw). The expression of the otapks and otanps genes correlated with the OTA produced by P. nordicum. Results from this work confirm that the traditional processing of Spanish dry-fermented sausages favours itself OTA synthesis by P. nordicum. Our findings may help in informed decision-making in relation to RH/temperature of drying chambers and shortening of the ripening process. This may be then effectively incorporated into the hygienic production system in the framework of HACCP together with other measures including the use of Penicillium nalgiovense as protective culture or the monitoring of otapks gene expression, and aw during the processing of dry-fermented sausages. All these strategies together may put ochratoxigenic Penicillia at a disadvantage and minimise OTA contamination risks in dry-fermented sausages.


Assuntos
Manipulação de Alimentos/métodos , Microbiologia de Alimentos/métodos , Produtos da Carne/microbiologia , Ocratoxinas/metabolismo , Penicillium/metabolismo , Animais , Dessecação , Fermentação , Perfilação da Expressão Gênica , Genes Bacterianos/genética , Concentração de Íons de Hidrogênio , Produtos da Carne/análise , Ocratoxinas/análise , Penicillium/genética , Suínos , Temperatura , Tempo , Água/metabolismo
3.
Food Chem ; 340: 128095, 2021 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-33007696

RESUMO

This article evaluates the use of emulsion gels (EGs) containing two different solid polyphenol extracts [from grape seed (R-EPG) or grape seed and olive (R-EPGO)] as animal fat replacers in the development of frankfurters. The incorporation of EGs improved their lipid content, particularly R-EPG and R-EPGO also contained high levels of phenolic compounds (hydroxytyrosol and flavanols). These frankfurters were judged acceptable by the panellists and showed good thermal and storage stability. Colour parameters, pH and textural properties were affected (p < 0.05) by the formulation, being significant the influence of polyphenols extracts. Spectroscopic results showed greater (p < 0.05) inter- and intramolecular lipid disorder in the frankfurters with EGs, irrespective of the presence of polyphenol extracts. Comparing the reduced-fat samples, R-EPG and R-EPGO showed the lowest (p < 0.05) total viable counts. Significant changes in pH and texture parameters were observed during chilled storage while lipid structure was not affected.


Assuntos
Gorduras na Dieta , Emulsões/química , Produtos da Carne , Polifenóis/química , Animais , Cor , Géis/química , Extrato de Sementes de Uva , Humanos , Concentração de Íons de Hidrogênio , Lipídeos/análise , Produtos da Carne/análise , Produtos da Carne/microbiologia , Olea/química , Azeite de Oliva/química , Espectroscopia de Infravermelho com Transformada de Fourier , Paladar
4.
Int J Food Microbiol ; 337: 108932, 2021 Jan 16.
Artigo em Inglês | MEDLINE | ID: mdl-33152570

RESUMO

Culturing methods are conventionally applied to investigate the contamination of food with several microorganisms after heat processing. However, with these methods, it is not possible to evaluate whether heat-treated meat products, such as cooked sausages, contained parts of spoiled meat. Therefore, two specific multiplex qPCRs were developed in this study in order to determine the microbiological quality of the raw materials used for these products. The PCR targets focused on four bacterial groups often found on meat (family Enterobacteriaceae, genus Pseudomonas, genus Staphylococcus and species Brochothrix thermosphacta). Specificity as well as sensitivity of the developed multiplex qPCRs, validated by using 68 microbial species, were 100%. The applicability of both multiplex qPCRs compared to culturing methods was performed using 96 meat samples (fresh and naturally spoiled) and 12 inhouse-made "Lyoner" sausages containing variable ratios of spoiled meat (0%, 5%, 12% and 25%; n = 3 for each group). Both methods showed similar results by evaluating the ∆log10 cfu/g, the relative accuracy and the t-test analysis (p > 0.05). Comparing qPCR results of the different sausage groups, a significant difference between sausages containing fresh meat and sausages containing spoiled meat (12% and 25%) was found only for Pseudomonas and B. thermosphacta in both raw and cooked sausages. The statistical difference between 5% vs. 12% and 25% spoiled meat in cooked sausages, was also found only for these two bacterial groups. The developed multiplex qPCRs were further applied to 30 commercially available "Bologna-type" sausages. The results showed a total of 14 sausages considered to be suspicious for Food Fraud. While the role of Staphylococcus spp. in meat spoilage remains unclear, Pseudomonas, Enterobacteriaceae and B. thermosphacta could together be used as an indicator for "spoiled meat" used in sausages. The developed qPCR systems in this study allow the detection of four relevant bacterial groups in the heated Bologna-type sausages and provide information about the hygienic quality of raw materials used. This method could thus be helpful for screening food suspected of Food Fraud.


Assuntos
Bactérias/genética , Microbiologia de Alimentos/métodos , Produtos da Carne/microbiologia , Carne/microbiologia , Reação em Cadeia da Polimerase , Animais , Brochothrix/genética , Enterobacteriaceae/genética , Temperatura Alta , Pseudomonas/genética , Staphylococcus/genética
5.
Int J Food Microbiol ; 337: 108947, 2021 Jan 16.
Artigo em Inglês | MEDLINE | ID: mdl-33181419

RESUMO

The objective of the study was to assess the antimicrobial effect of active essential oil components (EOs) namely (carvacrol (CA), cinnamaldehyde (CI) and thymol (TH)) on Listeria monocytogenes, Salmonella spp., and Escherichia coli O157:H7 in chicken tawook during storage at 4 and 10 °C. A marinade consisting of ingredients commonly used in the chicken tawook recipe was prepared and mixed with 1% and 2% v/v CA, CI or TH. The marinade with or without EOs was added to fresh chicken breast cubes inoculated with the foodborne pathogens. Afterward, marinated chicken "tawook" was stored at 4 and 10 °C covered with cling wrap to mimic chill and mild abuse storage conditions for up to 7 days. At 10 °C, the marinade decreased L. monocytogenes numbers on day 4 and 7 by about 2.4 log10 CFU/g as compared to unmarinated samples. Adding EOs to chicken tawook did not change L. monocytogenes numbers during storage at 4 and 10 °C. For Salmonella spp., the marinade decreased the numbers during 10 °C storage on day 4 and 7 by about 4.9 log10 CFU/g as compared to unmarinated samples. At 4 °C, EOs at 2% decreased Salmonella spp. on day 7 by 0.5 log10 CFU/g. One percent CI significantly decreased Salmonella by 1.5 log10 CFU/g, at day 4 of storage. At 10 °C, 1% CA, 2% CI, 1% and 2% TH decreased Salmonella spp. in the samples by 0.5 log10 CFU/g on day 7. The marinade decreased E. coli O157:H7 numbers on the chicken samples during 10 °C storage on day 4 and 7 by about 3.3 log10 CFU/g as compared to unmarinated samples. Regardless of storage day at 4 °C, EOs decreased E. coli O157:H7 populations in chicken tawook by ≤2.4 log10 CFU/g compared to samples without EOs, where the decrease was ≤1.4 log10 CFU/g. Moreover, no significant decrease in E. coli O157:H7 populations could be attributed to the addition of EOs in samples which were stored at 10 °C. Increasing the concentration of EOs from 1 to 2% seemed to have no significant effect in reducing the tested foodborne pathogen populations.


Assuntos
Antibacterianos/farmacologia , Armazenamento de Alimentos/métodos , Produtos da Carne/microbiologia , Óleos Voláteis/farmacologia , Animais , Galinhas , Contagem de Colônia Microbiana , Escherichia coli O157/efeitos dos fármacos , Escherichia coli O157/isolamento & purificação , Microbiologia de Alimentos , Listeria monocytogenes/efeitos dos fármacos , Listeria monocytogenes/isolamento & purificação , Salmonella/efeitos dos fármacos , Salmonella/isolamento & purificação , Temperatura
6.
Int J Food Microbiol ; 337: 108966, 2021 Jan 16.
Artigo em Inglês | MEDLINE | ID: mdl-33202297

RESUMO

Meat and meat products are perishable products that require the use additives to prevent the spoilage by foodborne microorganisms and pathogenic bacteria. Current trends for products without synthetic preservatives have led to the search for new sources of antimicrobial compounds. Essential oils (EOs), which has been used since ancient times, meet these goals since their effectiveness as antimicrobial agents in meat and meat products have been demonstrated. Cinnamon, clove, coriander, oregano, rosemary, sage, thyme, among others, have shown a greater potential to control and inhibit the growth of microorganisms. Although EOs are natural products, their quality must be evaluated before being used, allowing to grant the Generally Recognized as Safe (GRAS) classification. The bioactive compounds (BAC) present in their composition are linked to their activity, being the concentration and the quality of these compounds very important characteristics. Therefore, a single mechanism of action cannot be attributed to them. Extraction technique plays an important role, which has led to improve conventional techniques in favour of green emerging technologies that allow to preserve better target bioactive components, operating at lower temperatures and avoiding as much as possible the use of solvents, with more sustainable processing and reduced energy use and environmental pollution. Once extracted, these compounds display greater inhibition of gram-positive than gram-negative bacteria. Membrane disruption is the main mechanism of action involved. Their intense characteristics and the possible interaction with meat components make that their application combined with other EOs, encapsulated and being part of active film, increase their bioactivity without modifying the quality of the final product.


Assuntos
Anti-Infecciosos/farmacologia , Conservantes de Alimentos/farmacologia , Produtos da Carne/microbiologia , Óleos Voláteis/farmacologia , Anti-Infecciosos/química , Bactérias/efeitos dos fármacos , Bactérias/patogenicidade , Membrana Celular/efeitos dos fármacos , Filmes Comestíveis , Conservantes de Alimentos/química , Carne/microbiologia , Óleos Voláteis/química , Óleos Vegetais/química , Óleos Vegetais/farmacologia
7.
Int J Food Microbiol ; 336: 108899, 2021 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-33160121

RESUMO

Escherichia coli are commensal gastrointestinal microflora of humans, but few strains may cause food-borne diseases. Present study aimed to identify antimicrobial resistant (AMR), biofilm-forming E. coli from Indian dairy and meat products. A total of 32 E. coli isolates were identified and evaluated for biofilm-formation. EMC17, an E. coli isolate was established as a powerful biofilm-former that attained maximum biofilm-formation within 96 h on glass and stainless-steel surfaces. Presence and expression of virulence-associated genes (adhesins, invasins and polysaccharides) and ability to adhere and invade human liver carcinoma HepG2 cell lines implicates EMC17 to be pathotype belonging to Extra-intestinal Pathogenic E. coli (ExPEC). Antibiotic profiling of EMC17 identified it as multi-drug resistant (MDR) strain, possessing extended spectrum ß-lactamases (ESBL's) and biofilm phenotype. Early production of quorum sensing molecules (AHLs) alongside EPS production facilitated early onset of biofilm formation by EMC17. Furthermore, the biofilm-forming genes of EMC17 were significantly upregulated 3-27 folds in the biofilm-state. This study showed prevalence of MDR, biofilm-forming, pathogenic E. coli in Indian dairy and meat products that potentially serve as reservoirs for transmission of antimicrobial-resistant (AMR) genes of bacteria from food to humans and pose serious food safety threat.


Assuntos
Antibacterianos/farmacologia , Laticínios/microbiologia , Escherichia coli/efeitos dos fármacos , Escherichia coli/genética , Produtos da Carne/microbiologia , Animais , Biofilmes , Escherichia coli/patogenicidade , Inocuidade dos Alimentos , Doenças Transmitidas por Alimentos/microbiologia , Genótipo , Humanos , Índia , Fenótipo , Percepção de Quorum , Virulência/genética
8.
Artigo em Inglês | MEDLINE | ID: mdl-33371410

RESUMO

This study investigated eight types of Slovak dry fermented meat products (salami and sausages) that are available on the market and were produced by three different producers in different regions of Slovakia. The total counts of enterococci in these products ranged from 2.0 up to 6.0 cfu/g (log10). Three species were identified among the 15 selected enterococcal strains; Enterococcus faecium (8 strains), Enterococcus faecalis (3) and Enterococcus hirae (4). They were hemolysis-negative (γ-hemolysis) with a biofilm-forming ability, which was evaluated as low-grade biofilm formation, susceptible to conventional antibiotics and mainly susceptible to lantibiotic bacteriocins, namely, gallidermin and nisin; they even showed a higher susceptibility to gallidermin than to nisin. They were also susceptible to enterocin-durancin, but most strains showed resistance to enterocin A/P. This study indicated that bacteriocins can play a key role in preventing and/or protecting from undesirable bacterial multiplication or contamination in the food industry and that they have great potential for further experimental applications.


Assuntos
Bacteriocinas , Biofilmes , Enterococcus faecium , Produtos da Carne/microbiologia , Hidrocarbonetos Aromáticos com Pontes , Enterococcus , Testes de Sensibilidade Microbiana , Eslováquia
9.
Anim Sci J ; 91(1): e13466, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33043554

RESUMO

Sremski kulen is a wide diameter dry fermented sausage, produced from pork, seasoned with red spicy paprika, stuffed into pork cecum, and preserved by smoking, fermentation and drying. Due to specific ripening process, Sremski kulen is suitable for the accumulation of biogenic amines. Therefore, the aminogenesis was studied in traditionally produced Sremski kulen, taking into account the physicochemical parameters and microbial counts. The content of six biogenic amines (tryptamine, phenylethylamine, tyramine, histamine, putrescine, and cadaverine) was analyzed using high-performance liquid chromatography. The ripening process of Sremski kulen was slow followed by changes in aw and pH value as well as expressed proteolysis. The autochthonous microbiota showed pronounced decarboxylase activity. Tryptamine and phenylethylamine were detected at each examined ripening stage while histamine was not detected until the end of ripening (16.55 ± 2.33 mg/kg). Tyramine, cadaverine, and putrescine content significantly increased during the ripening period (p < .05). In the final product, cadaverine was the dominant biogenic amine (132.40 ± 5.05 mg/kg), followed by tyramine (115.80 ± 15.46 mg/kg) and putrescine (68.55 ± 2.39 mg/kg). Although the long ripening period greatly contributed to the accumulation of biogenic amines in final product, their content are not of concern from product safety aspects, but requires improvement in hygiene of production process.


Assuntos
Aminas Biogênicas/análise , Fermentação , Análise de Alimentos/métodos , Manipulação de Alimentos/métodos , Conservação de Alimentos/métodos , Qualidade dos Alimentos , Produtos da Carne/análise , Carne de Porco , Animais , Cadaverina/análise , Fenômenos Químicos , Cromatografia Líquida de Alta Pressão , Microbiologia de Alimentos , Inocuidade dos Alimentos , Concentração de Íons de Hidrogênio , Produtos da Carne/microbiologia , Proteólise , Putrescina/análise , Suínos , Tiramina/análise
10.
Int J Food Microbiol ; 334: 108851, 2020 Dec 02.
Artigo em Inglês | MEDLINE | ID: mdl-32911158

RESUMO

Numerous applications of proteolytic enzymes include dissociation of fermented meat products for the enumeration of `foodborne pathogenic bacteria. The use of trypsin for this cause is abandoned due to the high concentration of the enzyme affecting released bacteria. Papain, as a suggested replacement, and fig latex preparation with high extent of papain-like enzymes have the potential to be applied for bacteria enumeration. Both enzymatic preparations, originating from papaya and fig, showed a broader range of substrate specificities including gelatinolytic activity, especially prominent in the case of ficin and attributed to both, cysteine protease ficin and serine protease by the analysis of 2D zymography with specific inhibitors. The activity towards native collagen, mild in the case of papain, and extensive in the case of fig latex was proved by structural analysis of digested collagen by infrared spectroscopy. Further exploration of their potential for dissociation of fermented meat products showed that both papain and fig latex enzymes are stable in the presence of detergents Tween 20 and Triton X-100 and effective in the enumeration of Listeria monocytogenes. Gelatenolytic activity, and at least partial collagenolytic activity and stability in procedure conditions make papaya and fig latex proteases potent for this application in significantly lower concentrations than previously used enzymes. As a mixture of proteolytic enzymes with divergent characteristics, fig latex preparation shows higher efficiency in Listeria monocytogenes release than papain, conserved even in the presence of stronger non-ionic detergent Triton X-100.


Assuntos
Ficus/enzimologia , Microbiologia de Alimentos/métodos , Látex/metabolismo , Listeria monocytogenes/isolamento & purificação , Papaína/metabolismo , Carica/enzimologia , Colágeno/metabolismo , Contagem de Colônia Microbiana , Ficina/química , Ficina/metabolismo , Látex/química , Produtos da Carne/microbiologia , Especificidade por Substrato
11.
J Food Sci ; 85(9): 2857-2865, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32812228

RESUMO

The present study was aimed to develop Manihot esculenta and Carrageenan bio-based composite active film functionalized with anise, caraway, and nutmeg essential oils (EOs) and to assess the shelf life of chicken nuggets wrapped with the developed film at refrigeration storage. Overall, the Minimum Inhibitory Concentration (MIC) values of the three EOs ranged from 0.4 to 0.8% v/v of which nutmeg EO was found most effective. Incorporation of EOs in the film resulted in significant (P ˂ 0.05) decrease in tensile strength and water activity while elongation at break was significantly (P ˂ 0.05) increased. No significant (P ˃ 0.05) changes in thickness and Water Vapor Transmission Rate (WVTR) were observed. Based on physicomechanical and sensory evaluation, films incorporated with 0.5, 1, and 1% concentration of anise, nutmeg, and caraway EO were selected. Chicken nuggets overwrapped with aforementioned films were stored aerobically at refrigeration temperature (4 ± 1 °C) to evaluate antimicrobial, antioxidant, and sensory characteristics. The result indicated that pH, peroxide, free fatty acid (FFA), and thiobarbituric acide (TBA) value of treatments were significantly (P ˂ 0.05) lower than controls however significantly (P < 0.05) higher DPPH activity was observed in all treatments. The total plate count, psychrophilic count and, yeast and mold count were also significantly (P ˂ 0.01) lower in treatment groups and were within the permissible limits. The treated samples were well acceptable during whole storage period of 15 days. The application of composite, active edible bio-based film was found proficient in confining product quality attributes throughout storage. PRACTICAL APPLICATION: The majority of films used for packaging of meat and meat products are derived from synthetic "plastic" materials. The demerits associated with plastics have eventually led to explore natural alternatives such as edible films. The composite-active bio-based films have a huge potential to be molded for specific film properties based on requirements of product-specific packaging conditions.


Assuntos
Anti-Infecciosos/farmacologia , Antioxidantes/análise , Filmes Comestíveis , Embalagem de Alimentos/instrumentação , Produtos da Carne/análise , Óleos Voláteis/análise , Polímeros/química , Animais , Antioxidantes/farmacologia , Bactérias/efeitos dos fármacos , Bactérias/crescimento & desenvolvimento , Carragenina/química , Galinhas , Embalagem de Alimentos/métodos , Armazenamento de Alimentos , Fungos/efeitos dos fármacos , Fungos/crescimento & desenvolvimento , Humanos , Manihot/química , Produtos da Carne/microbiologia , Testes de Sensibilidade Microbiana , Óleos Voláteis/farmacologia , Polímeros/síntese química , Refrigeração , Paladar
12.
Int J Food Microbiol ; 332: 108770, 2020 Nov 02.
Artigo em Inglês | MEDLINE | ID: mdl-32634640

RESUMO

Moringa oleifera is a medicinal plant, and its seed oil is known to have high antioxidant properties. The byproduct obtained after oil extraction is called Moringa oleifera seed meal (MoSM), whose potential bioactivity has not been sufficiently documented. Therefore, this study was undertaken with the aim of identifying Moringa oleifera seed meal extract (ME) as a natural antibacterial and antioxidant alternative. First, the effect of solvent extraction of MoSM with 60% (v/v) ethanol combined with ultrasound (UAE) was determined at the sample-to-solvent ratio of 1: 10, with different time and power combinations of UAE. The lowest minimum inhibitory concentration (MIC) exhibited by ME at 200 W and 20 min (ME200/20) against both Escherichia coli among the gram-negative bacteria and Bacillus cereus among the gram-positive bacteria was 3.12 mg/g. The leakage of intracellular constituents as well as the damage of the B. cereus cells after being treated with ME were confirmed by measuring the absorbance of the supernatant at 260 and 280 nm and observation of the cells under a scanning electron microscope. Moreover, the highest total phenolic content was also recorded with ME200/20 at 460 mg gallic acid equivalent/g of extract, and the subsequent significantly higher (p < 0.05) antioxidant activity was determined to be 11.18 and 9.20 mg acetic acid equivalent/g of extract by 2,2-diphenyl-1-picrylhydrazyl and ferric reducing antioxidant power assays, respectively. The high-performance liquid chromatography results showed that gallic acid and vanillic acid were predominantly present in the extract, followed by quercetin, sinapic acid and chlorogenic acid. Interestingly, caffeic acid appeared in the sample treated with UAE only. The extract was finally applied with a chitosan-based coating to evaluate the antimicrobial activity against E. coli and B. cereus on raw chicken sausages in the concentration range of 1-5%. Incorporating 3% extract could inactivate B. cereus and E. coli for a 1.4 log reduction on day 3 and a 1.78 log reduction on day 6 of storage and, further, could significantly suppress the growth of both bacteria until day 9. Thus, this study confirmed the strong antibacterial and antioxidant properties of ME and its potential use in real food systems as a natural food antibacterial agent.


Assuntos
Antibacterianos/farmacologia , Antioxidantes/farmacologia , Filmes Comestíveis , Produtos da Carne , Moringa oleifera/química , Animais , Antibacterianos/análise , Antioxidantes/análise , Bactérias/efeitos dos fármacos , Bactérias/crescimento & desenvolvimento , Galinhas , Produtos da Carne/microbiologia , Testes de Sensibilidade Microbiana , Fenóis/análise , Fenóis/farmacologia , Extratos Vegetais/química , Extratos Vegetais/farmacologia , Sementes/química
13.
Int J Food Microbiol ; 332: 108769, 2020 Nov 02.
Artigo em Inglês | MEDLINE | ID: mdl-32622249

RESUMO

Controlling spoilage of the popular ethnic marinated beef "Shawarma" is crucial to achieve high quality, extend shelf-life, reduce food waste and meet the need of the globalized supply chain. Active essential oil (EO) components (thymol and carvacrol) were added at 0.4% and 0.8% (w/w) to preserve marinated beef, stored under aerobic or vacuum packaging. Microbiological and sensory (odor) parameters were assessed during 21 days at 4 °C. The treatments with higher EO concentration achieved higher antimicrobial activity than the lower ones and significantly reduced the mesophilic total viable count (TVC), lactic acid bacteria (LAB), Brochothrix thermosphacta, Pseudomonas spp., total coliforms, Escherichia coli, yeasts and molds. The higher EO concentration extended the microbiological shelf-life by 6 days, as judged by TVC and compared to the controls (aerobic and vacuum packaging) but was unacceptable sensorially. The lower EO concentration increased the microbiological shelf-life by 3 days and the sensorial shelf-life by 9 and > 12 days, under aerobic and vacuum conditions, respectively.


Assuntos
Cimenos/farmacologia , Conservação de Alimentos/métodos , Produtos da Carne/microbiologia , Timol/farmacologia , Ácido Acético/farmacologia , Animais , Bactérias/efeitos dos fármacos , Bactérias/crescimento & desenvolvimento , Bovinos , Contagem de Colônia Microbiana , Microbiologia de Alimentos , Fungos/efeitos dos fármacos , Fungos/crescimento & desenvolvimento , Óleos Voláteis/química , Óleos Voláteis/farmacologia
14.
Int J Food Microbiol ; 331: 108689, 2020 Oct 16.
Artigo em Inglês | MEDLINE | ID: mdl-32623291

RESUMO

Lactobacillus (L.) curvatus and L. sakei contain strains, which are assertive in sausage fermentation. Previous work has demonstrated differences in assertiveness at strain level within one species, and revealed either exclusion of competitors by complementary partner strains or their inhibition by single strains. This work addresses interspecies differences in the assertiveness of L. curvatus and L. sakei. Strain sets of L. curvatus and L. sakei were employed as starters in a fermented sausage model and their abundancy upon fermentation was determined by strain-specific MALDI-TOF MS identification. Generally, single or groups of L. sakei strains outcompeted L. curvatus strains. In multiple growth tests employing mMRS and mMSM it could be shown that assertive L. sakei strains can be predicted along their µ max in mMSM. Still, L. curvatus TMW 1.624 could suppress all L. curvatus and most L. sakei strains in competitive settings. This could be referred to its expression of several bacteriocins, which are active against all of the L. curvatus strains. Strain specific differences could be demonstrated in the susceptibility of L. sakei to bacteriocins, and in oxidative stress tolerance, which is higher in co-existing L. sakei strains than in the bacteriocin producer. This suggests that tolerance to bacteriocins and oxidative stress represent additional determinants for assertiveness, above previously reported bacteriocin production versus metabolic complementarism of partner strains.


Assuntos
Fermentação , Microbiologia de Alimentos , Lactobacillus sakei/metabolismo , Lactobacillus/metabolismo , Produtos da Carne/microbiologia , Interações Microbianas , Bacteriocinas/metabolismo , Reatores Biológicos
15.
Int J Food Microbiol ; 330: 108696, 2020 Oct 02.
Artigo em Inglês | MEDLINE | ID: mdl-32502760

RESUMO

Synthetic preservatives can have harmful effects on the body, so plant essential oils appear to be an attractive natural alternative. However, the use of essential oils is limited due to the low stability and possible negative effects on the sensory properties of food. Oil encapsulation was suggested as a way to overcome these drawbacks. The objective of this study was to encapsulate thyme essential oil and to evaluate its antioxidant and antimicrobial potential in vitro and in situ in of hamburger-like meat products. The casein-maltodextrin capsules produced by spray-drying were assessed for encapsulation efficiency, thermal stability, chemical compounds and morphology. Antioxidant activity was evaluated by DPPH, hydroxyl and nitric oxide methods, while antimicrobial activity was evaluated in vitro against four bacteria and in situ in hamburger-like products. The capsule showed high encapsulation efficiency and thermal stability, and spherical and irregular morphology. The casein-maltodextrin encapsulated essential oil showed antioxidant and antimicrobial activity against Staphylococcus aureus, Escherichia coli, Listeria monocytogenes and Salmonella Typhimurium tested in vitro and against thermotolerants coliforms and Escherichia coli in situ, showing potential for application as a natural preservative in food.


Assuntos
Antibacterianos/farmacologia , Conservação de Alimentos/métodos , Conservantes de Alimentos/farmacologia , Produtos da Carne/microbiologia , Óleos Voláteis/farmacologia , Thymus (Planta)/química , Antibacterianos/química , Antioxidantes/farmacologia , Bactérias/efeitos dos fármacos , Dessecação , Microbiologia de Alimentos , Conservantes de Alimentos/química , Temperatura Alta , Óleos Voláteis/química
16.
Int J Food Microbiol ; 324: 108624, 2020 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-32302878

RESUMO

Carbapenemase-producing Enterobacteriaceae (CPE) confer resistance to antibiotics that are of critical importance to human medicine. There have only been a few reported cases of CPEs in the European food chain. We report the first detection of a carbapenemase-producing Escherichia coli (ST 5869) in the Belgian food chain. Our aim was to characterize the origin of the carbapenem resistance in the E. coli isolate. The isolate was detected during the screening of 178 minced pork samples and was shown to contain the carbapenemase gene blaVIM-1 by PCR and Sanger sequencing. Whole genome short and long read sequencing (MiSeq and MinION) was performed to characterize the isolate. With a hybrid assembly we reconstructed a 190,205 bp IncA/C2 plasmid containing blaVIM-1 (S15FP06257_p), in addition to other critically important resistance genes. This plasmid showed only low similarity to plasmids containing blaVIM-1 previously reported in Germany. Moreover, no sequences existed in the NCBI nucleotide database that completely covered S15FP06257_p. Analysis of the blaVIM-1 gene cassette demonstrated that it likely originated from an integron of a Klebsiella plasmid reported previously in a clinical isolate in Europe, suggesting that the meat could have been contaminated by human handling in one of the steps of the food chain. This study shows the relevance of fully reconstructing plasmids to characterize their genetic content and to allow source attribution. This is especially important in view of the potential risk of antimicrobial resistance gene transmission through mobile elements as was reported here for the of public health concern blaVIM-1.


Assuntos
Enterobacteriáceas Resistentes a Carbapenêmicos/isolamento & purificação , Escherichia coli/isolamento & purificação , Genes Bacterianos , Produtos da Carne/microbiologia , Plasmídeos/genética , Proteínas de Bactérias/genética , Bélgica , Enterobacteriáceas Resistentes a Carbapenêmicos/genética , Escherichia coli/genética , Microbiologia de Alimentos , Humanos , Integrons , beta-Lactamases/genética
17.
An Acad Bras Cienc ; 92 Suppl 1: e20180557, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32348408

RESUMO

In Brazil and in other countries of the world, studies have been conducted to identify Listeria monocytogenes in cattle meat that is preferably consumed undercooked and, when marketed without meeting strict phytosanitary requirements, may cause outbreaks of listeriosis. In the such, foodborne outbreaks, the methods used for the detection of the pathogen and the efficiency associated with them are crucial for the proper assessment. In this study, we used the techniques biochemical and molecular for identification of the L. monocytogenes isolated from 30 samples of the fresh beef, marketed in ten butchers' shop of the free-fair from a municipality from the Bahia, Brazil. The results obtained from biochemical tests (catalase, motility, ß-hemolysis and carbohydrate fermentation), as well as PCR analysis for the hly gene (hemolysin production is an important factor in the pathogenesis of listeriosis) revealed that 50% of butchers shops presented bovine meat contaminated with bacteria of the Listeria sp. and confirmed that 54.16% of the analyzed meat samples were positive for L. monocytogenes. This study highlights the importance of microbiological surveillance in free-fair to minimize the exposure of consumers to this foodborne pathogen.


Assuntos
DNA Bacteriano/análise , Proteínas Hemolisinas/genética , Listeria monocytogenes/isolamento & purificação , Produtos da Carne/microbiologia , Animais , Brasil , Bovinos , Microbiologia de Alimentos , Proteínas Hemolisinas/análise , Listeria monocytogenes/genética
18.
Meat Sci ; 165: 108130, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32224414

RESUMO

The objectives of this study were to evaluate the effects of power ultrasound (nominal intensity 600 W·cm-2 for 10 min) and the addition of potassium chloride (KCl) on the physicochemical properties and sensorial acceptance of low sodium restructured cooked ham. Four treatments of low sodium restructured cooked ham (mean of 324.52 mg Na/100 g) were prepared: CT - Control Treatment; UsT - Ultrasound Treatment; KT - addition of 0.5% KCl; UsKT - Ultrasound Treatment and addition of 0.5% KCl. Ultrasound application reduced the total fluid released and improved the sensory acceptance for salty taste and flavor compared to CT. The addition of KCl showed the lowest values for total fluid release, the highest scores for all parameters of sensory acceptance, improved hardness and chewiness, which results were not statistically different from the results obtained by combining ultrasound and KCl. Therefore, the use of KCl was considered a technological and sensorial viable alternative to produce low sodium restructured cooked ham. CHEMICAL COMPOUNDS USED IN THIS RESEARCH: Methanol (PubChem CID: 887); Chloroform (PubChem CID: 6212); Sodium Carbonate (PubChem CID: 10340); Sodium hydroxide (PubChem CID: 14798); Boric acid (PubChem CID: 7628).


Assuntos
Produtos da Carne/análise , Cloreto de Potássio/química , Ondas Ultrassônicas , Animais , Cor , Comportamento do Consumidor , Humanos , Produtos da Carne/microbiologia , Cloreto de Sódio na Dieta , Suínos , Paladar
19.
Meat Sci ; 165: 108131, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32229407

RESUMO

Dry-cured ham is a shelf-stable product that can be contaminated with Listeria monocytogenes due to post-processing operations, compromising the compliance of zero tolerance policies (e.g. US Listeria rule). The present study quantifies the behavior of L. monocytogenes in sliced Spanish dry-cured ham of different water activity (aw) during storage at different temperatures. Inactivation kinetics were estimated by fitting primary models to the experimental data. The effect of temperature and aw on kinetic parameters was characterized through secondary polynomial models. L. monocytogenes viability decreased in all the assayed conditions, confirming that dry-cured ham is not only listeriostatic but listericidal. The fastest and highest reductions were observed at 25 °C, with 1 Log reduction after 6 and 9 days in Iberian and Serrano ham respectively. The work provides scientifically-based data and models to design a low-cost control measure based on a corrective storage as a post-lethality treatment to enhance the accomplishment of zero-tolerance requirements.


Assuntos
Armazenamento de Alimentos/métodos , Listeria monocytogenes/crescimento & desenvolvimento , Produtos da Carne/microbiologia , Animais , Contaminação de Alimentos/prevenção & controle , Microbiologia de Alimentos , Espanha , Suínos , Temperatura , Água/química
20.
J Food Sci ; 85(4): 1203-1212, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32118300

RESUMO

Listeria monocytogenes is often responsible for postprocessing contamination of ready-to-eat (RTE) products including cooked ham. As an emerging technology, atmospheric cold plasma (ACP) has the potential to inactivate L. monocytogenes in packaged RTE meats. The objectives of this study were to evaluate the effect of treatment time, modified atmosphere gas compositions (MAP), ham formulation, and post-treatment storage (1 and 7 days at 4 °C) on the reduction of a five-strain cocktail of L. monocytogenes and quality changes in ham subjected to in-package ACP treatment. Initial average cells population on ham surfaces were 8 log CFU/cm2 . The ACP treatment time and gas composition significantly (P < 0.05) influenced the inactivation of L. monocytogenes, irrespective of ham formulations. When MAP1 (20% O2 + 40% CO2 + 40% N2 ) was used, there was a significantly higher log reduction (>2 log reduction) in L. monocytogenes on ham in comparison to MAP2 (50% CO2 + 50% N2 ) and MAP3 (100% CO2 ), irrespective of ham formulation. Addition of preservatives (that is, 0.1% sodium diacetate and 1.4% sodium lactate) or bacteriocins (that is, 0.05% of a partially purified culture ferment from Carnobacterium maltaromaticum UAL 307) did not significantly reduce cell counts of L. monocytogenes after ACP treatment. Regardless of type of ham, storage of 24 hr after ACP treatment significantly reduced cells counts of L. monocytogenes to approximately 4 log CFU/cm2 . Following 7 days of storage after ACP treatment, L. monocytogenes counts were below the detection limit (>6 log reduction) when samples were stored in MAP1. However, there were significant changes in lipid oxidation and color after post-treatment storage. In conclusion, the antimicrobial efficacy of ACP is strongly influenced by gas composition inside the package and post-treatment storage. PRACTICAL APPLICATION: Surface contamination of RTE ham with L. monocytogenes may occur during processing steps such as slicing and packaging. In-package ACP is an emerging nonthermal technology, which can be used as a postpackaging decontamination step in industrial settings. This study demonstrated the influence of in-package gas composition, treatment time, post-treatment storage, and ham formulation on L. monocytogenes inactivation efficacy of ACP. Results of present study will be helpful to optimize in-package ACP treatment and storage conditions to reduce L. monocytogenes, while maintaining the quality of ham.


Assuntos
Embalagem de Alimentos/métodos , Conservação de Alimentos/métodos , Produtos da Carne/microbiologia , Gases em Plasma/farmacologia , Animais , Bacteriocinas/farmacologia , Contagem de Colônia Microbiana , Contaminação de Alimentos/análise , Embalagem de Alimentos/instrumentação , Conservação de Alimentos/instrumentação , Conservantes de Alimentos/farmacologia , Armazenamento de Alimentos , Listeria monocytogenes/efeitos dos fármacos , Listeria monocytogenes/crescimento & desenvolvimento , Produtos da Carne/análise , Lactato de Sódio/farmacologia , Suínos
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...