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1.
Food Chem ; 369: 130969, 2022 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-34500206

RESUMO

Modified atmosphere packaging (MAP) can inhibit microbial growth and prolong shelf life of fresh-cut cucumbers. This study compared the effects of different packaging gases on the growth of E. coli O157:H7 and sensory characteristics of fresh-cut cucumbers. Changes in key movement, adhesion, and oxidative stress genes expression of strain under optimal MAP and air were determined. Cell population density, the extracellular carbohydrate complex content and expression of curli fimbriae were evaluated. Results revealed that the growth of E. coli O157:H7 in fresh-cut cucumbers could be effectively inhibited under MAP (atmosphere = 2% O2, 7% CO2, 91% N2), and better maintained the sensory characteristics. Furthermore, the inhibition mechanism was revealed by inhibiting the expression of movement (fliC), adhesion (eaeA) and oxidative stress (rpoS and sodB) genes in E. coli O157:H7, reducing biofilm formation, extracellular carbohydrate production and curli fimbriae expression. Proper MAP can maintain the quality and safety of fresh-cut cucumbers.


Assuntos
Cucumis sativus , Escherichia coli O157 , Atmosfera , Contagem de Colônia Microbiana , Cucumis sativus/genética , Escherichia coli O157/genética , Microbiologia de Alimentos , Embalagem de Alimentos
2.
Food Chem ; 370: 131058, 2022 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-34560500

RESUMO

The present work optimized high-pressure homogenization (HPH) parameters for not-from-concentrate combined peach and carrot juices, based on a two-step comprehensive model using factor analysis and analytic hierarchy process methods. Treating combined juice with pressures over 200 MPa retained more amounts of the bioactive compounds (carotenoids and polyphenols) than non-homogenization. Nutrition-oriented optimization, with higher judgement weight on nutritional properties, and sense-oriented optimization, with higher weight on sensory properties, were set up. Combined juice (250 MPa, 1 pass and 25 °C) had the best quality, based on the nutrition- and sense-oriented models. Back propagation neural network (BPNN) models could predict antioxidant capacities of the combined juice with greater accuracy compared with stepwise linear regression. The relative errors of BPNN prediction model were ≤ 5%.


Assuntos
Manipulação de Alimentos , Sucos de Frutas e Vegetais , Carotenoides/análise , Microbiologia de Alimentos , Pressão
3.
Food Chem ; 371: 131134, 2022 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-34656920

RESUMO

Widespread use of traditional packaging constitutes a serious ecological problem leading to a shift to biodegradable and compostable materials. The aim of this work is to study the ability of a new biopackaging (BP), based on biodegradable and compostable material, to preserve the quality of organic chicken meat for 14 days in comparison with a polyethylene terephthalate (PET) material. Results showed that the indices of Biogenic Amines (BAs) and the 18 monitored Volatile Organic Compounds (VOCs) have a similar trend in both packaged meats. For example, the total BAs concentration in meat increased from 390 to 961 mg Kg-1 in BP and from 393 to 800 mg Kg-1 in PET, as well as the microbiological counts. The new biopackaging (BP) showed similar properties of non-biodegradable material (PET) to preserve the shelf life of organic chicken meat and it could be used instead of plastic materials to promote a circular economy.


Assuntos
Embalagem de Alimentos , Conservação de Alimentos , Animais , Galinhas , Microbiologia de Alimentos , Carne/análise
4.
Int J Food Microbiol ; 361: 109461, 2022 Jan 16.
Artigo em Inglês | MEDLINE | ID: mdl-34742144

RESUMO

The main objective of this study was to isolate and identify Staphylococcus aureus from retail raw red meat samples and evaluate their enterotoxin gene and antibiotic resistance profiles. A total of 452 retail raw meat samples, including beef (n = 200), sheep (n = 125), and lamb (n = 127) randomly purchased from various supermarkets and butchers in Ankara between July 2019 and November 2020, were tested for the prevalence of S. aureus. The S. aureus strain was identified using morphological and molecular (16S rRNA and nuc gene) methods. Moreover, nine Staphylococcal enterotoxin (SE) genes were screened using polymerase chain reaction. Antibiotic resistance of S. aureus was determined using the phenotypic disc diffusion method. The overall prevalence of S. aureus among screened samples was 21.23%. Additionally, 65.62% of S. aureus strains contained SE gene regions. The predominant SEs in the S. aureus strains were sea (50.79%), followed by sed (25.39%) and seb (23.80%). However, sec, see, seg, seh, sei, and sej genes were never detected. A substantial proportion (40-100%) of the isolates were found resistant to kanamycin, telithromycin, penicillin G, streptomycin, erythromycin, cloxacillin, ampicillin, pristinamycin, nalidixic acid, azithromycin, and ciprofloxacin. Multi-drug resistance (MDR) was observed in 96.87% of the S. aureus strains. These results show a low prevalence of S. aureus in raw red meat samples in Turkey. However, a high rate of SEA raises serious health concerns. Due to the high levels of MDR observed in this study, there is a need to strictly control antibiotic use in animals in Turkey.


Assuntos
Carne Vermelha , Infecções Estafilocócicas , Animais , Bovinos , Resistência Microbiana a Medicamentos , Enterotoxinas/genética , Microbiologia de Alimentos , Carne , Prevalência , RNA Ribossômico 16S , Ovinos , Staphylococcus aureus/genética , Turquia
5.
Int J Food Microbiol ; 361: 109444, 2022 Jan 16.
Artigo em Inglês | MEDLINE | ID: mdl-34749186

RESUMO

"Torta del Casar" is a Spanish soft-ripened cheese made with sheep's raw milk and subjected to a short ripening process, which favors the growth of pathogenic microorganisms including Listeria monocytogenes. The development of strategies to control pathogens and minimize health risks associated with the presence of L. monocytogenes in these products is of great interest. In this regard, the anti-Listeria activity of a whey protein hydrolysate (ProH) alone or combined with six lactic acid bacteria strains isolated from cheese was evaluated in this study as a biocontrol strategy using a "Torta del Casar" cheese-based medium. The most active combinations of lactic acid bacteria assayed induced a reduction higher than two logarithmic units in the growth of L. monocytogenes (serotype 4b) compared to their respective control when they were co-inoculated in "Torta del Casar" cheese-based medium at 7 °C for 7 days. In addition, the observed downregulation of some key virulence genes of L. monocytogenes suggests that the strain Lactiplantibacillus plantarum B2 alone and combined with the strain Lactiplantibacillus spp. B4 are good candidates to be used as biocontrol agents against L. monocytogenes growth in traditional soft cheeses based on raw milk during their storage at refrigeration temperatures.


Assuntos
Anti-Infecciosos , Queijo , Lactobacillales , Listeria monocytogenes , Animais , Queijo/análise , Microbiologia de Alimentos , Hidrolisados de Proteína , Ovinos , Virulência , Soro do Leite
6.
Int J Food Microbiol ; 361: 109462, 2022 Jan 16.
Artigo em Inglês | MEDLINE | ID: mdl-34749188

RESUMO

The ability of Salmonella to resist and adapt to harsh conditions is one of the major features that have made this microorganism such a relevant health hazard. However, the impact of these resistance responses on other aspects of Salmonella physiology, such as virulence and growth ability, is still not fully understood. The objective of this study was to determine the maximum growth rates (in three different media), virulence (adhesion and invasion of Caco-2 cells), and other phenotypic characteristics (biofilm-forming ability and antimicrobial resistance) of 23 Salmonella strains belonging to different serovars, and to compare them with their previously determined stress resistance parameters. Significant differences (p < 0.05) in growth rates, virulence, and biofilm-forming ability were found among the 23 strains studied. Nevertheless, whereas less than 3-fold change between the lowest and the highest growth rate was observed, the percentage of cells capable of invading Caco-2 cells varied more than 100-fold, that to form biofilms more than 30-fold, and the antibiotic MICs varied up to 512-fold, among the different strains. Results indicate that those strains with the highest cell adhesion ability were not always the most invasive ones and suggest that, in general terms, a higher stress resistance did not imply a reduced growth ability (rate). Similarly, no association between stress resistance and biofilm formation ability (except for acid stress) or antibiotic resistance (with minor exceptions) was found. Our data also suggest that, in Salmonella, acid stress resistance would be associated with virulence, since a positive correlation of that trait with adhesion and a negative correlation with invasion was found. This study contributes to a better understanding of the physiology of Salmonella and the relationship between bacterial stress resistance, growth ability, and virulence. It also provides new data regarding intra-specific variability of a series of phenotypic characteristics of Salmonella that are relevant from the food safety perspective.


Assuntos
Microbiologia de Alimentos , Salmonella , Biofilmes , Células CACO-2 , Humanos , Virulência
7.
Meat Sci ; 183: 108661, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34467880

RESUMO

The increasing concern of consumers about food quality and safety and their rejection of chemical additives has promoted the breakthrough of the biopreservation field and the development of studies on the use of beneficial bacteria and their metabolites as potential natural antimicrobials for shelf life extension and enhanced food safety. Control of foodborne pathogens in meat and meat products represents a serious challenge for the food industry which can be addressed through the intelligent use of bio-compounds or biopreservatives. This article aims to systematically review the available knowledge about biological strategies based on the use of lactic acid bacteria to control the proliferation of undesirable microorganisms in different meat products. The outcome of the literature search evidenced the potential of several strains of lactic acid bacteria and their purified or semi-purified antimicrobial metabolites as biopreservatives in meat products for achieving longer shelf life or inhibiting spoilage and pathogenic bacteria, especially when combined with other technologies to achieve a synergistic effect.


Assuntos
Conservação de Alimentos/métodos , Lactobacillales/fisiologia , Produtos da Carne/microbiologia , Animais , Antibacterianos/farmacologia , Bactérias/efeitos dos fármacos , Bacteriocinas/farmacologia , Microbiologia de Alimentos , Lactobacillales/metabolismo , Produtos da Carne/análise
8.
Front Cell Infect Microbiol ; 11: 718840, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34778102

RESUMO

Listeria monocytogenes remains a significant public health threat, causing invasive listeriosis manifested as septicemia, meningitis, and abortion, with up to 30% of cases having a fatal outcome. Tracking the spread of invasive listeriosis requires an updated knowledge for virulence factors (VFs) and antimicrobial resistance features, which is an essential step toward its clinical diagnosis and treatment. Taking advantage of high-throughput genomic sequencing, we proposed that the differential genes based on the pathogenomic composition could be used to evaluate clinical observations and therapeutic options for listeriosis. Here, we performed the comparative genomic analysis of 60 strains from five continents with a diverse range of sources, representing serotypes 1/2a, 1/2b, 1/2c, and 4b, comprising lineage I and lineage II and including 13 newly contributed Chinese isolates from clinical cases. These strains were associated with globally distributed clonal groups linked with confirmed foodborne listeriosis outbreak and sporadic cases. We found that L. monocytogenes strains from clonal complex (CC) CC8, CC7, CC9, and CC415 carried most of the adherence and invasive genes. Conversely, CC1, CC2, CC4, and CC6 have the least number of adherence and invasive genes. Additionally, Listeria pathogenicity island-1 (LIPI-1), LIPI-2, intracellular survival, surface anchoring, and bile salt resistance genes were detected in all isolates. Importantly, LIPI-3 genes were harbored in CC3, CC224, and ST619 of the Chinese isolates and in CC1, CC4, and CC6 of other worldwide isolates. Notably, Chinese isolates belonging to CC14 carried antibiotic resistance genes (ARGs) against ß-lactams (bla TEM-101 , bla TEM-105) and macrolide (ermC-15), whereas CC7 and CC8 isolates harbored ARGs against aminoglycoside (aadA10_2, aadA6_1), which may pose a threat to therapeutic efficacy. Phylogenomic analysis showed that CC8, CC7, and CC5 of Chinese isolates, CC8 (Swiss and Italian isolates), and CC5 and CC7 (Canadian isolates) are closely clustered together and belonged to the same CC. Additionally, CC381 and CC29 of Chinese isolates shared the same genomic pattern as CC26 of Swiss isolate and CC37 of Canadian isolate, respectively, indicating strong phylogenomic relation between these isolates. Collectively, this study highlights considerable clonal diversity with well-recognized virulence and antimicrobial-resistant determinants among Chinese and worldwide isolates that stress to design improved strategies for clinical therapies.


Assuntos
Listeria monocytogenes , Listeriose , Antibacterianos/farmacologia , Canadá , Farmacorresistência Bacteriana/genética , Microbiologia de Alimentos , Genômica , Humanos , Listeria monocytogenes/genética , Virulência/genética
9.
Appl Microbiol Biotechnol ; 105(23): 8615-8627, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34731280

RESUMO

There has been a growing interest in traditional dairy (such as raw milk cheeses) and meat products, in recent years. However, these products are suitable and nutrient medium and may be easily contaminated by microorganisms such as Enterobacteriaceae. Enterobacteriaceae are considered to be the indicator bacteria for microbiological quality of food and hygiene status of a production process. Additionally, the food contaminated by Enterobacteriaceae poses a microbiological risk for consumers. In fact, the contamination of raw milk and meat by Enterobacteriaceae amid manufacturing may easily occur from various environmental sources, and this group of bacteria is frequently detected in dairy and meat products. Therefore, monitoring the microbiological quality of the used raw material and maintaining high standards of hygiene in the production process are mandatory for a high quality of traditional products and the safety of the potential consumers. The goal of this review is to present the most recent survey on Enterobacteriaceae growth, number, and distribution in raw milk cheeses and meat, as well as to discuss the sources of contamination and methods of control. KEY POINTS: • Enterobacteriaceae: role and importance in milk and meat products, EU legal regulations • Dynamics, distribution, and survival of Enterobacteriaceae in milk and meat • Mechanisms of control of Enterobacteriaceae in dairy products.


Assuntos
Enterobacteriaceae , Leite , Animais , Contaminação de Alimentos/análise , Microbiologia de Alimentos , Inocuidade dos Alimentos , Carne
10.
Anal Chim Acta ; 1184: 339051, 2021 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-34625270

RESUMO

Foodborne pathogens are still a significant source of morbidity and mortality worldwide. In addition to this the current methodologies to track these microorganisms cannot cope with the current intensive production systems, thus novel methods are of outmost importance. DNA-based methods have already demonstrated suitable to address this issue, but most of them are targeted methods such as real-time PCR (qPCR), meaning that one will only find what is looking for, thus taking the risk of missing relevant pathogens in a given sample. To overcome this limitation we have developed an easy-to-implement methodology which enables the detection of several pathogens simultaneously by using long-read Next Generation Sequencing (NGS) with MinION. The method was named "semi-targeted" due to the combination of a non-targeted detection method, NGS, with the usage of selective media in order to partially eliminate non-pathogenic interfering bacteria. To this end, we included an enrichment step for the recovery of different pathogens, namely Salmonella Enteritidis and Typhimurium, Listeria monocytogenes and Escherichia coli O157:H7, after DNA extraction and library preparation, the samples were analyzed with MinION implementing the low-cost Flongle Flow Cells. The methodology was successfully evaluated in spiked milk samples with an excellent agreement with the results obtained by qPCR and culture-based methods. The method can provide accurate results after only 2 h of sequencing. Sample multiplexing, along with the lower cost of the Flongle Flow Cells and the reduced price of the MinION platform, make the assay cost-effective that is of importance for the food industry. Starting the method with a classical microbiological approach, the enrichment, the method is easy to implement in testing laboratories, it provides flexibility in terms of potential pathogens to be detected, and the positive results can be easily confirmed following culture-based, or other type, of confirmation procedures.


Assuntos
Escherichia coli O157 , Listeria monocytogenes , Escherichia coli O157/genética , Microbiologia de Alimentos , Listeria monocytogenes/genética , Salmonella enteritidis/genética , Sensibilidade e Especificidade
11.
Biosensors (Basel) ; 11(10)2021 Sep 24.
Artigo em Inglês | MEDLINE | ID: mdl-34677310

RESUMO

For sensitive and fast detection of Escherichia coli O157:H7, organic and inorganic hybrid Au/Fe3+ nanoclusters (NCs) were synthesized for the first time using gold nanoparticles (GNPs), bovine serum albumin, ferric chloride, phosphate-buffered saline, and antibodies. The Au/Fe3+ porous spongy NCs with large surface area showed excellent bio-specific capability for E. coli O157:H7. GNPs in Au/Fe3+ NCs functioned as signal enhancers, significantly increasing the Raman signal via the metathesis reaction product of Prussian blue and obviously improving the detection sensitivity. We combined the novel Au/Fe3+ NCs with antibody-modified magnetic nanoparticles to create a biosensor capable of sensitive detection of E. coli O157:H7, which showed a good linear response (101 to 106 cfu/mL), high detection sensitivity (2 cfu/mL), and good recovery rate (93.60-97.50%) in spiked food samples. These results make the biosensor well-suited for food safety monitoring. This strategy achieves the goal of sensitive and quantitative detection of E. coli O157:H7.


Assuntos
Técnicas Eletroquímicas , Escherichia coli O157 , Microbiologia de Alimentos , Técnicas Biossensoriais , Ouro , Limite de Detecção , Nanopartículas Metálicas , Porosidade , Análise Espectral Raman
12.
BMC Res Notes ; 14(1): 397, 2021 Oct 26.
Artigo em Inglês | MEDLINE | ID: mdl-34702364

RESUMO

OBJECTIVE: Microbial analysis in milk preserved using heat-assisted Pulsed Electric Field (PEF) need to be assessed. In this study we analyze the microbial quality and virulence-associated genes in milk samples preserved using heat-assisted PEF from several producers in Indonesia. RESULTS: Milk samples were collected consisting of raw milk, milks taken after the heating, PEF, mixing, cooling, and packaging. Microbiological and Polymerase Chain Reaction (PCR) detection for virulence genes were performed. Heat-assisted PEF treatment gave 2.7-7.47 log reduction for TPC; 1.6-2.56 log reduction for MPN number; 3.13-6.48 log reduction for S. aureus; and for B. cereus there was an increase of 0.76 log and a reduction of 0.46 log. While milk samples from thermal pasteurization gave log reduction numbers of TPC, MPN, and S. aureus respectively 5.28; 2.56; and 4.73, for B. cereus was increasing 2.4 log. Producer C performed the best results with significant reduction compared with others (p < 0.005). There were no colonies of L. monocytogenes found in all of the samples. PCR results showed that milk samples possessed virulence genes 17.5% (10/57) of invA genes, 54.4% (31/57) of nheA genes, 68.4% (39/57) of cytK genes, 38.6% (22/57) of nuc genes, 63.2% (36/57) of ileS genes, while hly and actA genes were not detected.


Assuntos
Temperatura Alta , Leite , Animais , Contagem de Colônia Microbiana , Eletricidade , Microbiologia de Alimentos , Staphylococcus aureus , Virulência/genética
13.
Molecules ; 26(20)2021 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-34684821

RESUMO

Currently, there is a growing demand for flavorings, especially of natural origin. It is worth paying attention to the biotechnological processes of flavor production, characterized by simplicity, high efficiency and relatively low cost. In this study, we analyzed the ability of the Galac tomyces geotrichum mold to transform by-products of the dairy industry: sour whey and buttermilk to complex flavour mixtures with pleasant, honey-rose aroma. Furthermore, the aroma complexity of the fermentation product has been carefully identified applying a sensomic approach involving the use of gas chromatography-olfactometry (GC-O), gas chromatography-mass spectrometry (GC-MS) and stable isotope dilution assay (SIDA) to identify and quantify aroma compounds. Based on the calculation of odor activity value (OAV), 13 key aroma compounds were present in both tested variants. The highest OAVs were found for phenylacetaldehyde (honey-like) in the buttermilk variant (912) and 2-phenylethanol (rose-like) in the sour whey variant (524). High values of this indicator were also recorded for phenylacetaldehyde (319) and 3-methyl-1-butanol with a fruity aroma (149) in the sour whey culture. The other compounds identified are 3-methylbutanal (malty), 2,3-butanedione (cheesy), isovaleric acid (cheesy), 3-(methylthio)-propanal (boiled potato), butanoic acid (vinegar), (E)-2-nonenal (fatty), ethyl furaneol (burnt sugar), dimethyl trisulfide (cabbage), and acetic acid (vinegar).


Assuntos
Leitelho/análise , Leitelho/microbiologia , Microbiologia de Alimentos , Geotrichum/metabolismo , Odorantes/análise , Soro do Leite/química , Soro do Leite/microbiologia , Acetaldeído/análogos & derivados , Acetaldeído/análise , Biotecnologia , Biotransformação , Fermentação , Aromatizantes/metabolismo , Tecnologia de Alimentos , Cromatografia Gasosa-Espectrometria de Massas , Humanos , Olfatometria , Álcool Feniletílico/análise , Paladar , Compostos Orgânicos Voláteis/análise
14.
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
15.
Molecules ; 26(19)2021 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-34641607

RESUMO

The application of bacterial cultures in food fermentation is a novel strategy to increase the "natural" levels of bioactive compounds. The unique ability of lactic acid bacteria (LAB) to produce folate, B vitamins, and conjugated linolenic acid cis9trans11 C18:2 (CLA) during cold storage up to 21 days was studied. Although some species of LAB can produce folates and other important nutrients, little is known about the production ability of yogurt starter cultures. Pasteurized milk samples were inoculated with four different combinations of commercially available yogurt vaccines, including starter cultures of Bifidobacterium bifidum. Both the type of vaccine and the time of storage at 8 °C had a significant effect on the folate and CLA contents in the tested fermented milks. The highest folate content (105.4 µg/kg) was found in fresh fermented milk inoculated with Lactobacillus delbrueckii, Streptococcus thermophilus, and Bifidobacterium bifidum. Only the mix of Lactobacillus delbrueckii subsp. bulgaricus, Streptococcus thermophilus, and Bifidobacterium bifidum showed potential (59% increase) to synthesize folate during seven days of storage. A significant increase in the content of CLA, when compared to fresh fermented milk, was observed during cold storage for up to 21 days in products enriched with Bifidobacterium bifidum.


Assuntos
Produtos Fermentados do Leite/microbiologia , Ácido Fólico/metabolismo , Lactobacillales/metabolismo , Ácidos Linoleicos Conjugados/metabolismo , Leite/metabolismo , Leite/microbiologia , Complexo Vitamínico B/metabolismo , Animais , Bifidobacterium bifidum/metabolismo , Biofortificação/métodos , Fermentação , Microbiologia de Alimentos , Lactobacillus delbrueckii/metabolismo , Probióticos , Streptococcus thermophilus/metabolismo , Fatores de Tempo
16.
Molecules ; 26(19)2021 Oct 08.
Artigo em Inglês | MEDLINE | ID: mdl-34641615

RESUMO

Pathogenic E. coli infection is one of the most widespread foodborne diseases, so the development of sensitive, reliable and easy operating detection tests is a key issue for food safety. Identifying bacteria with a fluorescent medium is more sensitive and faster than using chromogenic media. This study designed and synthesized a ß-galactosidase-activatable fluorescent probe BOD-Gal for the sensitive detection of E. coli. It employed a biocompatible and photostable 4,4-difluoro-3a,4a-diaza-s-indancene (BODIPY) as the fluorophore to form a ß-O-glycosidic bond with galactose, allowing the BOD-Gal to show significant on-off fluorescent signals for in vitro and in vivo bacterial detection. This work shows the potential for the use of a BODIPY based enzyme substrate for pathogen detection.


Assuntos
Compostos de Boro/química , Escherichia coli/isolamento & purificação , Corantes Fluorescentes/química , Galactose/metabolismo , alfa-Galactosidase/metabolismo , Técnicas Biossensoriais , Ativação Enzimática , Escherichia coli/enzimologia , Proteínas de Escherichia coli/química , Proteínas de Escherichia coli/metabolismo , Microbiologia de Alimentos , Galactose/química , Sensibilidade e Especificidade , alfa-Galactosidase/química
17.
Arch Microbiol ; 203(10): 5907-5919, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34647141

RESUMO

Listeria monocytogenes is a pathogenic bacterium present in several environments able to survive and proliferate in food processing plants, contaminating products that when ingested can lead to listeriosis. Worldwide, the bacterium has been isolated from foods of animal and plant origin and its occurrence in ready-to-eat foods is a challenge for food processing establishments. Serotypes 1/2a, 1/2b, 1/2c, and 4b related to 95% of listeriosis cases have been detected in different foods and presented resistance to common antibiotics such as tetracycline and penicillin. The analysis and dissemination of the presence of L. monocytogenes in different foods are essential to anchor control and prevention measures. In Brazil, despite the lack of official data on contamination by L. monocytogenes, some studies have reported the presence of bacteria in various foods and food processing environments. Thus, this review focuses on presenting the main characteristics of the L. monocytogenes, resistance to antimicrobial agents, and occurrence in several foods and countries from 2010 to 2020.


Assuntos
Listeria monocytogenes , Listeriose , Animais , Manipulação de Alimentos , Microbiologia de Alimentos , Listeriose/epidemiologia , Listeriose/prevenção & controle , Sorogrupo
18.
Int J Food Microbiol ; 360: 109437, 2021 Dec 16.
Artigo em Inglês | MEDLINE | ID: mdl-34673328

RESUMO

Peanuts and peanut products are significant revenue sources for smallholder farmers in the Senegalese peanut basin. However, microbial contamination during production and storage can greatly affect market access for producers. Peanut products have emerged as possible sources of foodborne illness, encouraging discussions on international standards for peanuts. In this study, we interviewed 198 households throughout the Senegalese peanut basin to assess current production practices, storage methods, and producers' prior knowledge of microbial contamination using a 162-question survey. A member of each household orally completed the survey with a trained enumerator and the results were compared to microbiological results obtained from peanut samples collected at the time of the interview using linear regression and an analysis of variance model. Samples were collected from stored peanuts at each household; peanuts were shelled and total Enterobacteriaceae, coliform, and yeast and mold populations were enumerated. Of the 198 samples analyzed, 13.0% and 13.6% were greater than the upper detection limits for Enterobacteriaceae and coliforms, respectively. A total of 21.2% of samples were above the detection limit for yeast and mold populations. Only 22.7% and 18.7% of producers were aware of pathogenic bacteria or aflatoxins, respectively; there were no significant differences in observed microbial populations between household who took preventative measures against microbial contamination and those who did not. Additionally, four households reported washing their kitchen utensils before using them to eat and 60.1% reported always washing their hands before eating. Enumerators were asked to report peanut storage container type and if the containers were stored off the ground at the time of collection. While the interaction between storage container type and if the container was stored off the ground was significant for Enterobacteriaceae and coliforms, it was not significant for yeast and mold. Additionally, when storage container type and if peanuts were stored off the ground were included in the regression model, these methods were predictive of contamination levels for Enterobacteriaceae and coliforms. To our knowledge, this is the first study to analyze the relationship among Enterobacteriaceae, coliforms, and yeast and mold contamination and producer knowledge of Senegalese peanuts. These results provide preliminary data to inform future studies to determine pathogen prevalence and impactful preventative measures to minimize microbial contamination of peanuts produced in Senegal.


Assuntos
Arachis , Enterobacteriaceae , Contagem de Colônia Microbiana , Contaminação de Alimentos/análise , Microbiologia de Alimentos , Inocuidade dos Alimentos , Saccharomyces cerevisiae , Senegal
19.
Int J Food Microbiol ; 360: 109438, 2021 Dec 16.
Artigo em Inglês | MEDLINE | ID: mdl-34715483

RESUMO

Listeria monocytogenes is a foodborne pathogen ubiquitously found in nature and which has been isolated from food and food processing environments. This study aimed to characterize L. monocytogenes strains isolated from the production and processing environments of frozen sliced mushrooms (Agaricus bisporus). An analysis was executed along the mushroom processing chain including one mushroom grower and two mushroom processing factories. A total of 153 L. monocytogenes strains were isolated, which could be grouped in three PCR serogroups, namely, serogroup 1/2a-3a (39.2%), serogroup 1/2b-3b-7 (34.0%) and serogroup 4b-4d-4e (26.8%). A selection of 44 L. monocytogenes strains isolated from the processing environment after cleaning and disinfection (C&D) and from frozen sliced mushrooms was genotyped by whole genome sequencing (WGS), because these strains pose a potential risk for product contamination after C&D and for human consumption. Multilocus sequence typing (MLST) revealed 11 clonal complexes (CCs), with strains belonging to CC1, CC4, CC37 and CC87 being detected in both processing factories. Comparative WGS analysis of the 44 strains showed the presence of Listeria pathogenicity island 1 (LIPI-1) with a disrupted version of actA in all CC1, CC4, CC5, CC59 strains, and all but one CC224 strains. Notably, both inlA and inlB were detected as full-length loci in every strain, except for inlA in a CC6 strain that harbored a three amino acid deletion. LIPI-3 was detected in all CC1, CC4, CC6 and CC224 strains, while LIPI-4 was detected in all CC4 and CC87 strains. In addition, antibiotic susceptibility tests showed susceptibility towards fourteen antibiotics tested. The bcrABC operon was found in one CC5 strain, that showed a higher tolerance towards benzalkonium chloride than any other strain tested with confluent growth till 12.5 µg/ml for the CC5 strain compared to 2.5 µg/ml for the other strains. This study highlights that the ecology of L. monocytogenes in the frozen sliced mushroom production chain is highly diverse, and shows the importance of hygienic measures to control L. monocytogenes along the frozen sliced mushroom production chain.


Assuntos
Agaricus , Listeria monocytogenes , Listeriose , Microbiologia de Alimentos , Genômica , Humanos , Listeria monocytogenes/genética , Tipagem de Sequências Multilocus
20.
Int J Food Microbiol ; 360: 109441, 2021 Dec 16.
Artigo em Inglês | MEDLINE | ID: mdl-34717152

RESUMO

Biofilms pose a serious challenge to the food industry. Higher resistance of biofilms to any external stimuli is a major hindrance for their eradication. In this study, we compared the growth dynamics and benzalkonium chloride (BAC) resistance of dual species Listeria monocytogenes-Escherichia coli 48 h biofilms formed on stainless steel (SS) coupons surfaces under batch and fed-batch cultures. Differences between both operational culture conditions were evaluated in terms of total viable adhered cells (TVAC) in the coupons during 48 h of the mixed-culture and of reduction of viable adhered cells (RVAC) obtained after BAC-treatment of a 48 h biofilm of L. monocytogenes-E. coli formed under both culture conditions. Additionally, epifluorescence microscopy (EFM) and confocal scanning microscopy (CLSM) permitted to visualize the 2D and 3D biofilms structure, respectively. Observed results showed an increase in the TVAC of both strains during biofilm development, being the number of E. coli adhered cells higher than L. monocytogenes in both experimental systems (p < 0.05). Additionally, the number of both strains were higher approximately 2.0 log CFU/coupon in batch conditions compared to fed-batch system (p < 0.05). On the contrary, significantly higher resistance to BAC was observed in biofilms formed under fed-batch conditions. Furthermore, in batch system both strains had a similar reduction level of approximately 2.0 log CFU/coupon, while significantly higher resistance of E. coli compared to L. monocytogenes (reduction level of 0.69 and 1.72 log CFU/coupon, respectively) (p < 0.05) was observed in fed-batch system. Microscopic image visualization corroborated these results and showed higher complexity of 2D and 3D structures in dual species biofilms formed in batch cultures. Overall, we can conclude that the complexity of the biofilm structure does not always imply higher resistance to external stimuli, and highlights the need to mimic industrial operational conditions in the experimental systems in order to better assess the risk associated to the presence of pathogenic bacterial biofilms.


Assuntos
Compostos de Benzalcônio , Listeria monocytogenes , Compostos de Benzalcônio/farmacologia , Biofilmes , Contagem de Colônia Microbiana , Escherichia coli , Microbiologia de Alimentos , Aço Inoxidável/análise
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