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1.
PLoS One ; 17(5): e0267972, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35533187

RESUMO

Listeria monocytogenes can cause listeriosis, and people with hypoimmunity such as pregnant women, infants and fetuses are at high risk of invasive infection. Although the incidence of listeriosis is low, the fatality rate is high. Therefore, continual surveillance and rapid epidemiological investigation are crucial for addressing L. monocytogenes. Because of the popularity of next-generation sequencing, obtaining the whole-genome sequence of a bacterium is easy. Several genome-based typing methods are available, and core-genome multilocus sequence typing (cgMLST) is the most recognized methods. Using cgMLST typing to compare L. monocytogenes whole-genome sequences (WGS) with those obtained across distinct regions is beneficial. However, the concern is how to incorporate the powerful cgMLST method into investigations, such as by using source tracing. Herein, we present an easy-to-use web service called-LmTraceMap (http://lmtracemap.cgu.edu.tw/hua_map/test/upload.php; http://120.126.17.192/hua_map/test/upload.php) that can help public-health professionals rapidly trace closely related isolates worldwide and visually inspect them in search results on a world map with labeled epidemiological data. We expect the proposed service to improve the convenience of public health investigations.


Assuntos
Listeria monocytogenes , Listeriose , Feminino , Microbiologia de Alimentos , Genoma Bacteriano , Humanos , Listeria monocytogenes/genética , Listeriose/epidemiologia , Listeriose/microbiologia , Tipagem de Sequências Multilocus/métodos , Gravidez , Sequenciamento Completo do Genoma/métodos
2.
BMJ Case Rep ; 15(5)2022 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-35523512

RESUMO

Listeria monocytogenes is a foodborne pathogen, typically associated with contaminated dairy products and deli meats. L. monocytogenes can lead to severe infections in high-risk patient populations; in neonates, listeriosis is rare but carries a high rate of neurological morbidity and mortality. Here a case of neonatal listeriosis, in the newborn of a young Hispanic mother who frequently ate queso fresco (a fresh Mexican cheese), is presented. Pregnant women are commonly counselled to avoid unpasteurised dairy during the pregnancy, but many are unaware that soft cheeses, and other food products, may pose risks for perinatal infection. L. monocytogenes remains a cause of food-related outbreaks and maternal and neonatal sepsis around the world, and healthcare providers should ensure that expectant mothers are carefully counselled regarding potential sources.


Assuntos
Queijo , Doenças Fetais , Doenças do Recém-Nascido , Listeria monocytogenes , Listeriose , Surtos de Doenças , Feminino , Microbiologia de Alimentos , Humanos , Recém-Nascido , Listeriose/diagnóstico , Listeriose/tratamento farmacológico , Gravidez
3.
Braz J Biol ; 84: e259449, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35544793

RESUMO

The presence of pathogenic bacteria in food is considered as a primary cause of food-borne illness and food quality deterioration worldwide. The present study aimed to determine the effectiveness of five essential oils (EOs) against multidrug-resistant foodborne pathogens. In the current study Gram-negative bacteria (Escherichia, Enterobacter, Citrobacter, Proteus, Pseudomonas, and Klebsiella) and the Gram-positive bacteria Staphylococcus were isolated from raw milk and biochemically characterized. The anti-bacterial effect of different antibiotics and EOs (thyme, oregano, lemongrass, mint, and rosemary) was determined using the standard disc diffusion method. The antibiogram study revealed that Gram-negative bacteria were highly resistant to penicillin while Staphylococcus was resistant to streptomycin, amoxicillin, and lincomycin. Moderate resistance was observed to doxycycline, amikacin, enrofloxacin, kanamycin and cefixime. Isolates were found less resistant to gentamycin, chloramphenicol, and ciprofloxacin. EOs showed a broad range of antimicrobial activity against all bacteria except P. aeruginosa. Of these, thyme was more effective against most of the multi-drug resistant bacterial strains and formed the largest zone of inhibition (26 mm) against Escherichia followed by oregano oil (18 mm) against Staphylococcus (p<0.05). Klebsiella spp and Citrobacter spp showed resistance to mint and lemongrass oil respectively. The EOs such as lemongrass, mint and rosemary were less active against all the bacteria. The findings of the recent study suggest the use of EOs as natural antibacterial agents for food preservation.


Assuntos
Óleos Voláteis , Thymus (Planta) , Animais , Antibacterianos/farmacologia , Bactérias , Microbiologia de Alimentos , Testes de Sensibilidade Microbiana , Leite , Óleos Voláteis/química , Óleos Voláteis/farmacologia , Thymus (Planta)/química
4.
Arch Microbiol ; 204(6): 294, 2022 May 04.
Artigo em Inglês | MEDLINE | ID: mdl-35507075

RESUMO

There is a need for new natural products with antimicrobial activity to treat multidrug resistant bacteria that can cause human illness. Some of them are foodborne pathogens. Two different Gram-negative psychrotrophic strains were isolated from healthy trout river samples (Salmo trutta). Based on phenotypic characterization, proteomics, genotyping and phylogenetic analyses of 16 rRNA gene, strains TCPS12 and TCPS13 were identified as Shewanella baltica and Pseudomonas fragi, respectively. Both of them produced an exopolysaccharide that showed antimicrobial activity against four foodborne pathogens. P. fragi supernatant (AS13) showed higher antimicrobial activity than S. baltica supernatant (AS12) against all tested pathogens. The stability of the antimicrobial activity of AS13 was assessed against Enterococcus faecalis ATCC 29212 under different conditions. This solution was stable when exposed for 30 min to temperatures ranging from 40 to 100 °C. In addition, it retained its activity within a pH range of 2-8 during 2 h of incubation, showing higher activity at pH 6. Serine proteases and α-amylase inactivated significantly the antimicrobial activity of AS13, suggesting that the active molecule could most likely be a glycoprotein. These products are interesting for their possible application as biopreservatives in the food industry.


Assuntos
Anti-Infecciosos , Microbiologia de Alimentos , Animais , Filogenia , Rios , Truta
5.
J Infect Dev Ctries ; 16(3): 507-515, 2022 Mar 31.
Artigo em Inglês | MEDLINE | ID: mdl-35404857

RESUMO

INTRODUCTION: In several developing countries the slaughter of meat producing animals is still practiced in traditional slaughterhouses. In the Mansoura slaughterhouse, animals are subjected to various stressors and treated with cruelty, in addition to unhygienic treatment and handling of animal carcasses. Hence, this study was designed to investigate the meat quality from cattle, buffalo, and sheep carcasses processed in an old-fashioned slaughterhouse from Mansoura city, Egypt, in the context of pre-slaughter stress. METHODOLOGY: The bleeding efficiency and the ultimate pH (pHu) of carcasses were tested, along with the effect of post-slaughter handling practice on the microbiological properties of meat. RESULTS: From the 351 examined animals, the ultimate pH (pHu) was less than 5.8 in 81 cases (23.1%) and higher than 6.0 in 165 cases (47%). Furthermore, 45 (12.8%), 270 (76.9%), and 36 (10.3%) of the tested carcasses were well-, moderate- and imperfectly-bled, respectively. Cultivation using the wet-dry triple swab technique sampled from the outer surfaces of cattle, buffalo, and sheep carcasses revealed that about 47.9% of the tested carcasses were contaminated, with total viable count levels exceeding 7 log10 cfu/cm2, and 42.7% were contaminated with Enterobacteriaceae, with levels > 3 log10 cfu/cm2. The molds and yeasts from the tested carcasses had lower counts (< 2 log10 cfu/cm2). CONCLUSIONS: Results indicated neglect in terms of sanitary measures during slaughtering and dressing of carcasses, with subsequent higher microbial contamination and impaired meat quality. Therefore, the traditional slaughtering facilities should be modernized to increase their meat producing efficiency, subsequently leading to exportation possibilities.


Assuntos
Matadouros , Carne , Animais , Bovinos , Contagem de Colônia Microbiana , Egito , Enterobacteriaceae , Manipulação de Alimentos/métodos , Microbiologia de Alimentos , Carne/microbiologia , Ovinos
6.
PLoS One ; 17(4): e0266059, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35381048

RESUMO

The study aimed to recover diarrheagenic Escherichia coli strains from processed ready-to-eat (RTE) foods in Yenagoa, Nigeria and characterize them using culture-based and molecular methods. Three hundred RTE food samples were collected randomly from different food outlets between February 2021 and August 2021 and assessed for the occurrence of E. coli using standard bacteriological procedures. The virulence factor formation and antibiotic susceptibility profile of the isolates was carried out using standard microbiological procedures. Polymerase chain reaction (PCR) was used to confirm the identity of the isolates via specific primers and further used to assay the diarrheagenic determinants of the E. coli isolates. The prevalence of E. coli positive samples based on the proliferation of E. coli on Chromocult coliform agar forming purple to violet colonies was 80(26.7%). The population density of E. coli from the RTE foods ranged from 0-4.3 × 104 ± 1.47 CFU/g. The recovered E. coli isolates (n = 62) were resistant to antibiotics in different proportions such as ampicillin 62(100%), aztreonam 47(75.81%) and chloramphenicol 43(69.35%). All the recovered E. coli isolates were resistant to ≥ 2 antibiotics. The multiple antibiotic-resistant index (MARI) ranged from 0.13-0.94 with 47(75.8%) of isolates having MARI >2. A total of 48(77.4%) of the isolates were multidrug-resistant (MDR). The proportion of extracellular virulence factor formation is as follows: protease 12(19.35%), curli 39(62.9%), cellulose 21(33.89%), ornithine decarboxylase 19(30.65%) and aesculin hydrolysis 14(22.58%). The overall proportion of diarrheagenic E. coli was 33/62(53.2%). The distributions of typical diarrheagenic E. coli includes: tETEC 9(14.5%), tEPEC 13(20.9%), tEAEC 6(9.7%), tEIEC 2(3.2%) and tEHEC 3(4.8%). The proportions of atypical strains include aETEC 10(16.1%), aEAEC 5(8.1%), aEPEC 1(1.6%) and aEIEC 3(4.8%). This study demonstrated that some RTE foods sold in Yenagoa, Nigeria, are contaminated and constitute a probable human health hazard. Thus, there is a need for intensive surveillance of this isolate in RTE foods variety to spot evolving AMR phenotypes and avert food-borne infections.


Assuntos
Escherichia coli , Microbiologia de Alimentos , Antibacterianos/farmacologia , Escherichia coli/genética , Humanos , Nigéria , Fatores de Virulência/genética
7.
Molecules ; 27(7)2022 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-35408652

RESUMO

The consumption of ready-to-eat (RTE) leafy vegetables has increased rapidly due to changes in consumer diet. RTE products are perceived as fresh, high-quality, and health-promoting. The monitoring of the RTE quality is crucial in relation to safety issues. This study aimed to evaluate the maintenance of RTE rocket salad freshness packed under modified atmospheres. A portable E-nose, the electrolyte leakage test (which measures the index of leaf damage-ILD), and NIR spectroscopy and Aquaphotomics were employed. Two trials were carried out, using the following gas mixtures: (A) atmospheric air (21% O2, 78% N2); (B) 30% O2, 70% N2; (C) 10% CO2, 5% O2, 85% N2. Samples were stored at 4 °C and analyzed at 0, 1, 4, 7, 11, and 13 days. ANOVA, PCA, PLS were applied for data processing. E-nose and ILD results identified the B atmosphere as the best for maintaining product freshness. NIR spectroscopy was able to group the samples according to the storage time. Aquaphotomics proved to be able to detect changes in the water structure during storage. These preliminary data showed a good agreement NIR/ILD suggesting the use of NIR for non-destructive monitoring of the damage to the plant membranes of RTE rocket salad.


Assuntos
Nariz Eletrônico , Verduras , Contagem de Colônia Microbiana , Eletrólitos , Microbiologia de Alimentos , Espectroscopia de Luz Próxima ao Infravermelho , Verduras/química
8.
Curr Microbiol ; 79(5): 148, 2022 Apr 09.
Artigo em Inglês | MEDLINE | ID: mdl-35397016

RESUMO

The aim of this research was to investigate the antifungal potential of lactic acid bacteria (LAB) isolated from Turkish spontaneous sourdough collected in summer and winter seasons from 25 different small bakeries in Trabzon, Giresun, Ordu, and Samsun. Lactic acid bacteria (933 isolates) were screened for inhibition of three common food spoilage molds (Aspergillus flavus, Aspergillus niger, and Penicillium expansum). Eight LAB isolates identified as Weissella cibaria 908, Lactiplantibacillus plantarum subsp. plantarum 2114, Leuconostoc pseudomesenteroides 2619, L. plantarum subsp. plantarum 2702, Fructilactobacillus sanfranciscensis 2709, Levilactobacillus brevis 2216Y, L. pentosus Y118, and L. plantarum subsp. plantarum Y201 by 16 S rRNA sequencing, which were found to have high antifungal activity against all the test molds. The antifungal activity of cell free supernatants from LAB isolates was not altered after thermal treatment and proteolytic enzyme proteinase K. The cell free supernatants obtained from LAB showed a high antifungal effect against molds with inhibition zone diameter up to 20 mm at pH 3.0, but no inhibitory activity was determined after pH neutralization. Moreover, all cell free suspension samples were able to maintain their efficacy up to a 1:4 dilution. The antifungal activity of supernatants was mostly related to organic acid content, especially lactic acid ranged from 4.33 to 8.41 g/L. The results indicated that eight bacterial isolates obtained from spontaneous Turkish sourdough could constitute biopreservative cultures, which may be used in food industry.


Assuntos
Lactobacillales , Lactobacillus brevis , Antifúngicos/química , Antifúngicos/farmacologia , Aspergillus niger , Fermentação , Microbiologia de Alimentos , Lactobacillales/genética
9.
Food Res Int ; 155: 111069, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35400447

RESUMO

Nyons table olives, named after the French city where they are processed, are naturally fermented black table olives. Their specificity relies on the use of the "Tanche" olive variety harvested at full maturity and their slow spontaneous fermentation in 10% salt brine driven by yeast populations. This study aimed at investigating the benefit of inoculating autochthonous consortia to produce Nyons table olives by fermentation in 10% salt brine and in reduced salt conditions (8%). Two strategies were evaluated: inoculation with a defined autochthonous consortium and inoculation by spent brine backslopping. To define the consortium, yeasts were selected among 48 autochthonous isolates and key features included high halotolerance, low pectinolytic and proteolytic activities, however none had ß-glucosidase activities. The consortium included eight yeast strains with distinct technological properties belonging to five dominant species, i.e. Citeromyces nyonsensis, Pichia membranifaciens, Wickerhamomyces anomalus, Zygotorulaspora mrakii and Candida atlantica. Fermentation trials were conducted over a year and compared by evaluating microbial community shifts (16S and ITS metagenetics) and volatile profiles (GC-MS). Regarding fermentations with the defined consortium, four out of five species implanted in early stages while one, Pichia membranifaciens, persisted and largely dominated by the end of the fermentation. Altogether, inoculation with the defined consortium did not disrupt microbial shifts compared to traditional fermentations although minor differences were observed in volatile profiles. The backslopping method yielded the highest impact on microbial populations and olive volatile profiles, with higher ester abundances at the end of fermentation. Finally, reduced salt in brine gave very promising results as no deleterious effects on microbial communities, volatile dynamics but also safety criteria of the olives were observed compared to traditional fermented olives.


Assuntos
Olea , Fermentação , Microbiologia de Alimentos , Pichia , Sais , Cloreto de Sódio , Leveduras
10.
Food Res Int ; 155: 111072, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35400450

RESUMO

Foodborne outbreaks and recalls of pathogen-contaminated low-moisture foods (LMFs, foods with water activity at 25 °C < 0.85) have led to numerous scientific studies on bacterial persistence, as well as newly developed industrial interventions. Conducting microbial tests of LMFs, lab tests, or validation studies in pilot plans requires complete information on protocols and parameters that need to be aware of-in particular, understanding how factors influence the thermal resistance of bacterial pathogen in LMFs is critical in designing any thermal processes. This review provides detailed information on the general protocols of microbial studies of LMFs: from pertinent pathogen identification to microbial validation studies. In particular, it reviewed the detailed procedures (e.g., lawn-harvest method), analytical protocols (e.g., recovery and enumeration of pathogens in LMFs), and specialized tools that have been utilized (even widely accepted) in laboratory-based microbial studies of LMFs. It also summarized the factors that influence the microbial validation studies. This article could support the intervention of existing pasteurization processes in the LMF industry, promoting the microbial safety of LMFs.


Assuntos
Microbiologia de Alimentos , Pasteurização , Alimentos , Pasteurização/métodos , Água/análise
11.
Food Res Int ; 155: 111075, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35400453

RESUMO

Zoning is typically adopted by food manufacturers and classified into three different zones including Zone 1 (food contact surface), Zone 2 (proximity to food and food contact surfaces) and Zone 3 (remote surfaces from processing). In this study, environmental surfaces belonging to these three zones were sampled during food processing in a fresh-cut vegetables (FVs) processing facility located in Beijing, China. Bacterial loads in terms of aerobic plate count and coliform count were evaluated by culture-dependent techniques. The profile and diversity of bacterial community in these three zones were investigated by high-throughput sequencing. Zone 1 showed similar microbiota and predominated by Pseudomonas and Acinetobacter, while the predominant genera on Zone 2 or 3 were quite varied among different processing steps. The SourceTracker analysis showed that most of the bacteria (above 80%) on surfaces were from unknown sources, while sorting and disinfection & cleaning steps contributed equally to the bacterial community of cutting areas. Microbial association network analysis revealed strong positive interactions of Comamonas and Janthinobacterium with Myroides and Serratia, respectively, whereas Pseudomonas showed no significant correlation with other genera. The function of microbial communities was predicted based on BugBase 16S rRNA database, and the results indicated that the proportions of potential biofilm-forming bacteria were above 70% in all samples, and species of Pseudomonas, Comamonas, Chryseobacterium and Janthinobacterium were opportunistic pathogens or spoilage bacteria. This study evaluated the bacteria risks including bacterial load, composition, as well as potential bacterial interaction, function and microbial transfer on food processing surfaces, which will facilitate our better understanding on the cross-contaminations and preventions of harmful microorganism in FVs processing industry.


Assuntos
Microbiota , Verduras , Bactérias/genética , Microbiologia de Alimentos , Pseudomonas , RNA Ribossômico 16S/genética , Verduras/microbiologia
12.
Food Res Int ; 155: 111088, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35400463

RESUMO

Salmonella enterica is a leading human pathogen responsible for foodborne outbreaks worldwide. In the last decade, foods with low water activity (aw) and high-fat content have been involved in an increased occurrence of foodborne outbreaks. This research focuses on the foodstuff tahini, which is often linked to Salmonella infection outbreaks and recalls. Thermal treatments are suggested to reduce microbial populations in tahini, but little is known about its effectiveness against Salmonella. Our major objectives were to study the survival of Salmonella Typhimurium in tahini treated at temperatures ≥ 70 °C, and to identify food related factors that could influence its survival. Based on our experimental results the thermal treatments at 70 °C, 80 °C and 90 °C are suitable to inactivate only a partial population of Salmonella. The death of Salmonella in tahini matches a biphasic logarithmic inactivation model, with a maximal 3-log reduction after 1 h at 90 °C. Moreover, we observed that a second thermal treatment the day after the first treatment, is significantly less effective compared with the first thermal treatment. The inactivation rates of Salmonella in 100% tahini are almost 4-log lower than in water/tahini emulsions at 70 °C, with negative linear correlation between D-value and aw, and the Salmonella susceptibility to heat in sesame oil/tahini emulsions is affected by the matrix of pre-acclimation. Bacteria that had been acclimated in tahini kept their heat resistance, while acclimation in sesame oil before mixing in the preheated oil/tahini emulsions resulted in a sharp decline within 2 min at 70 °C. According to these findings, tahini producers' current pasteurization processes are not sufficient to achieve the required 5-log reduction. Furthermore, we suggest that due to the tahini heterogenicity, the aw in the micro-environment of each bacterium, which is shaped by the tahini substances, plays an essential role in Salmonella's survival in tahini at temperatures ≥ 70 °C.


Assuntos
Microbiologia de Alimentos , Salmonella typhimurium , Emulsões , Humanos , Óleo de Gergelim , Água/análise
13.
Food Res Int ; 155: 111098, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35400471

RESUMO

Microorganisms in low-moisture foods (LMFs) exhibit prolonged survivability and high heat resistance. Various external factors (water, food texture, nutritional compounds, etc.) influence the microbial heat resistance in LMFs; yet, the influential degree of each factor is not fully understood. In this study, the thermal resistance parameters (D and z values) of Salmonella enterica Enteritidis PT 30 (S. Enteritidis) at 80, 85, and 90 °C at the room-temperature water activity (aw, 25°C) of 0.32 ± 0.02 were measured. A series of egg powders with different fat and protein ratios (obtained by mixing egg white and yolk powders) were chosen as the model foods. Primary and secondary models were built from the isothermal inactivation kinetics of S. Enteritidis in the tested samples. The importance of fat and protein was then confirmed by controlling the water activity at the treatment temperature (aw, treatment temperature) via thermal water activity cells. The survivor curves of S. Enteritidis fitted well with the Weibull-type and log-linear models. The D values of S. Enteritidis increased with increasing fat (0-56.7%, w.b.) and decreasing protein contents (83.59-31.81%, w.b.). Incorporating the modified Bigelow model into the log-linear model yielded the zfat and zprotein of 58.96 and 57.14, respectively. At the controlled aw, 90°C of 0.32 ± 0.02, the D90°C values of S. Enteritidis increased remarkably (P < 0.05), but the values in egg white, whole egg, and egg yolk powders (11.73 ± 1.24, 23.82 ± 2.0, and 60.0 ± 2.4 min) were remarkably different. Our study identified that the influential degrees of fat, protein (zfat and zprotein values), and aw on the thermal resistance of S. Enteritidis in egg powders is in the order: aw,treatment temperature > fat > protein. Fat considerably increased the thermal resistance of S. Enteritidis even at the same aw,treatment temperature. This study quantified the effect of fat and protein on the thermal resistance of S. Enteritidis and emphasized the non-negligible effects of food components in LMFs' microbial safety.


Assuntos
Salmonella enterica , Salmonella enteritidis , Microbiologia de Alimentos , Pós , Água/análise
14.
J Nanobiotechnology ; 20(1): 167, 2022 Mar 31.
Artigo em Inglês | MEDLINE | ID: mdl-35361208

RESUMO

BACKGROUND: Salmonella Enteritidis (S. Enteritidis) being one of the most prevalent foodborne pathogens worldwide poses a serious threat to public safety. Prevention of zoonotic infectious disease and controlling the risk of transmission of S. Enteriditidis critically requires the evolution of rapid and sensitive detection methods. The detection methods based on nucleic acid and conventional antibodies are fraught with limitations. Many of these limitations of the conventional antibodies can be circumvented using natural nanobodies which are endowed with characteristics, such as high affinity, thermal stability, easy production, especially higher diversity. This study aimed to select the special nanobodies against S. Enteriditidis for developing an improved nanobody-horseradish peroxidase-based sandwich ELISA to detect S. Enteritidis in the practical sample. The nanobody-horseradish peroxidase fusions can help in eliminating the use of secondary antibodies labeled with horseradish peroxidase, which can reduce the time of the experiment. Moreover, the novel sandwich ELISA developed in this study can be used to detect S. Enteriditidis specifically and rapidly with improved sensitivity. RESULTS: This study screened four nanobodies from an immunized nanobody library, after four rounds of screening, using the phage display technology. Subsequently, the screened nanobodies were successfully expressed with the prokaryotic and eukaryotic expression systems, respectively. A sandwich ELISA employing the SE-Nb9 and horseradish peroxidase-Nb1 pair to capture and to detect S. Enteritidis, respectively, was developed and found to possess a detection limit of 5 × 104 colony forming units (CFU)/mL. In the established immunoassay, the 8 h-enrichment enabled the detection of up to approximately 10 CFU/mL of S. Enteriditidis in milk samples. Furthermore, we investigated the colonization distribution of S. Enteriditidis in infected chicken using the established assay, showing that the S. Enteriditidis could subsist in almost all parts of the intestinal tract. These results were in agreement with the results obtained from the real-time PCR and plate culture. The liver was specifically identified to be colonized with quite a several S. Enteriditidis, indicating the risk of S. Enteriditidis infection outside of intestinal tract. CONCLUSIONS: This newly developed a sandwich ELISA that used the SE-Nb9 as capture antibody and horseradish peroxidase-Nb1 to detect S. Enteriditidis in the spike milk sample and to analyze the colonization distribution of S. Enteriditidis in the infected chicken. These results demonstrated that the developed assay is to be applicable for detecting S. Enteriditidis in the spiked milk in the rapid, specific, and sensitive way. Meanwhile, the developed assay can analyze the colonization distribution of S. Enteriditidis in the challenged chicken to indicate it as a promising tool for monitoring S. Enteriditidis in poultry products. Importantly, the SE-Nb1-vHRP as detection antibody can directly bind S. Enteritidis captured by SE-Nb9, reducing the use of commercial secondary antibodies and shortening the detection time. In short, the developed sandwich ELISA ushers great prospects for monitoring S. Enteritidis in food safety control and further commercial production.


Assuntos
Contaminação de Alimentos , Microbiologia de Alimentos , Carne , Leite , Salmonella enteritidis , Animais , Galinhas , Ensaio de Imunoadsorção Enzimática , Microbiologia de Alimentos/métodos , Peroxidase do Rábano Silvestre/metabolismo , Carne/microbiologia , Leite/microbiologia , Salmonella enteritidis/isolamento & purificação
15.
PLoS One ; 17(4): e0258435, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35421088

RESUMO

The aim of the present study was to assess the microbial quality of five ready-to-eat food such as bread, pasta, rice with sauce, beans and milk sold in five localities of Burkina Faso namely, Ouagadougou, Bobo-Dioulasso, Dakola, Cinkansé and Niangoloko. One hundred and one samples were collected and microbial quality were assessed by evaluating the food hygiene indicators such as total aerobic mesophilic flora, total coliforms, thermotolerant coliforms, yeast and mould. Food safety indicators such as Escherichia coli, Salmonella, coagulase-positive staphylococci, Clostridium perfringens and Bacillus cereus were also tested for contamination. Samples were tested according to ISO guidelines for all parameters. The results showed that 74 (73.27%) of samples were satisfactory while 15 (14.85%) were acceptable and 12 (11.88%) were not satisfactory according to international standards. Among the food safety indicators sought, Escherichia coli was detected in two samples and Bacillus cereus in four samples. Most of the analyzed food exhibited good hygiene behavior within the acceptable limits and the highest of not satisfactory rate was observed in milk powder and rice with sauce. Ouagadougou samples recorded the highest number of not satisfactory samples. Despite the general quality was satisfactory, the presence of specific microorganisms such as coliforms is indicative of the poor hygiene surrounded these foods. It is therefore necessary to train and follow up the vendors in the handling of equipment, hand-washing practices and selling environment hygiene for better improvement of the quality of the street foods.


Assuntos
Microbiologia de Alimentos , Salmonella , Animais , Bacillus cereus , Burkina Faso , Contagem de Colônia Microbiana , Escherichia coli , Contaminação de Alimentos/análise , Manipulação de Alimentos , Leite
16.
Microbiology (Reading) ; 168(4)2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-35451951

RESUMO

The control of bacterial contaminants on meat is a key area of interest in the food industry. Bacteria are exposed to a variety of stresses during broiler processing which challenge bacterial structures and metabolic pathways causing death or sublethal injury. To counter these stresses, bacteria possess robust response systems that can induce shifts in the transcriptome and proteome to enable survival. Effective adaptive responses, such as biofilm formation, shock protein production and metabolic flexibility, require rapid induction and implementation at a cellular and community level to facilitate bacterial survival in adverse conditions. This review aims to provide an overview of the scientific literature pertaining to the regulation of complex adaptive processes used by bacteria to survive the processing environment, with particular focus on species that impact the quality and safety of poultry products like Campylobacter spp., Salmonella enterica and Pseudomonas spp.


Assuntos
Aves Domésticas , Salmonella enterica , Animais , Galinhas , Microbiologia de Alimentos , Carne/microbiologia , Aves Domésticas/microbiologia
17.
Food Res Int ; 155: 110987, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-35400412

RESUMO

Both lean meat and fat together contribute to the consumer impression of traditional Chinese bacon. The quality of this meat product is mainly dependent on numerous biochemical reactions and microbes. For the first time, this study reveals the microbial community succession and metabolic characteristics of the fat portion during the processing of traditional Chinese bacon by high-throughput sequencing and untargeted metabolomics (ultra-high performance liquid chromatography, UHPLC). The results showed that Proteobacteria and Firmicutes were the predominant bacterial phyla in traditional Chinese bacon. At the genus level, 15 core genera (relative abundance >1%) were identified, including Salinivibrio, Staphylococcus, Brochothrix, Vibrio, Psychrobacter, Acinetobacter, Carnobacterium, Aeromonas, Pseudomona, Cobetia, Macrococcus, Enterobacter, Kocuria, unclassified-f-Vibrionaceae, and Empedobacter. Distinct separation between different groups were identified by principal component analysis, revealing significant differences in the metabolic characteristics of different samples. A total of 262 metabolites were identified, and most of the metabolites belonged to lipids and lipid-like molecules, of which 60 were identified as differential metabolites. Results of correlation analysis indicated that some differential metabolites were significantly positively correlated with dominant bacteria, such as Salinivibrio, Vibrio, Cobetia and Staphylococcus, which reinforced the fact that microorganisms have an indispensable role in the quality formation of traditional Chinese bacon.


Assuntos
Microbiota , Carne de Porco , Bactérias , China , Microbiologia de Alimentos
18.
Food Res Int ; 155: 111056, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-35400434

RESUMO

The objective of this study was to investigate the effect of air packaging (AP), modified atmosphere packaging (MAP, 40% CO2/60 % N2) and vacuum packaging (VP) on the dynamic changes of bacterial communities and volatile organic compounds (VOCs) in braised chicken stored at 4 ℃. Physicochemical characteristics and microbiological parameters were also measured. Results showed that MAP and VP groups obtained a slower growth rate of total viable count (TVC) and better sensory scores than AP groups. High throughput sequencing showed that Proteobacteria and Firmicutes were the dominant phyla in braised chicken samples. Additionally, different packaging conditions had significant effects on the succession of bacteria at the genus level. At the beginning of storage, Sphingomonas, Bradyrhizobium, Acinetobacter, Psychrobacter and Phyllobacterium dominated the microflora of braised chicken. However, on day 28, Staphylococcus and Serratia became the predominant genera in MAP and VP samples, respectively. Furthermore, thirty-two VOCs were detected in all braised chicken samples. Following the results of Spearman's correlation analysis, positive correlations were observed between Staphylococcus and all the compounds except for heptanoic acid. These results might provide valuable information regarding the quality improvement of braised chicken during refrigerated storage.


Assuntos
Galinhas , Compostos Orgânicos Voláteis , Animais , Bactérias , Microbiologia de Alimentos , Embalagem de Alimentos/métodos , Vácuo , Compostos Orgânicos Voláteis/análise
19.
Toxins (Basel) ; 14(4)2022 Apr 16.
Artigo em Inglês | MEDLINE | ID: mdl-35448897

RESUMO

In the last decade, foodborne outbreaks and individual cases caused by bacterial toxins showed an increasing trend. The major contributors are enterotoxins and cereulide produced by Bacillus cereus, which can cause a diarrheal and emetic form of the disease, respectively. These diseases usually induce relatively mild symptoms; however, fatal cases have been reported. With the aim to detected potential toxin producers that are able to grow at refrigerator temperatures and subsequently produce cereulide, we screened the prevalence of enterotoxin and cereulide toxin gene carriers and the psychrotrophic capacity of presumptive B. cereus obtained from 250 food products (cereal products, including rice and seeds/pulses, dairy-based products, dried vegetables, mixed food, herbs, and spices). Of tested food products, 226/250 (90.4%) contained presumptive B. cereus, which communities were further tested for the presence of nheA, hblA, cytK-1, and ces genes. Food products were mainly contaminated with the nheA B. cereus carriers (77.9%), followed by hblA (64.8%), ces (23.2%), and cytK-1 (4.4%). Toxigenic B. cereus communities were further subjected to refrigerated (4 and 7 °C) and mild abuse temperatures (10 °C). Overall, 77% (94/121), 86% (104/121), and 100% (121/121) were able to grow at 4, 7, and 10 °C, respectively. Enterotoxin and cereulide potential producers were detected in 81% of psychrotrophic presumptive B. cereus. Toxin encoding genes nheA, hblA, and ces gene were found in 77.2, 55, and 11.7% of tested samples, respectively. None of the psychrotrophic presumptive B. cereus were carriers of the cytotoxin K-1 encoding gene (cytK-1). Nearly half of emetic psychrotrophic B. cereus were able to produce cereulide in optimal conditions. At 4 °C none of the examined psychrotrophs produced cereulide. The results of this research highlight the high prevalence of B. cereus and the omnipresence of toxin gene harboring presumptive B. cereus that can grow at refrigerator temperatures, with a focus on cereulide producers.


Assuntos
Bacillus cereus , Depsipeptídeos , Bacillus cereus/genética , Eméticos , Enterotoxinas/análise , Enterotoxinas/genética , Microbiologia de Alimentos
20.
Foodborne Pathog Dis ; 19(5): 349-358, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35443788

RESUMO

Shigella flexneri, a common Gram-negative foodborne pathogen, is widely distributed in fresh-cut fruits and vegetables, unpasteurized milk, and food processing environments. The aims of this study were to evaluate the antibacterial effects of 405-nm light-emitting diode (LED) treatment on S. flexneri and to investigate the possible mechanism. The results showed that LED irradiation (360 min) reduced the number of S. flexneri in phosphate-buffered saline by 3.29 log colony-forming unit (CFU)/mL (initial bacterial count: 6.81 log CFU/mL). The cells in reconstituted infant formula, cells on fresh-cut carrot slices, and biofilm-associated cells on stainless steel surfaces were reduced by 1.83 log CFU/mL, 7.00 log CFU/cm2, and 4.35 log CFU/cm2 following LED treatment for 360, 120, and 120 min, respectively. LED treatment damaged both DNA and cell wall of S. flexneri and changed cell morphology and cell membrane permeability. In addition, LED treatment decreased total cell protein concentration of S. flexneri. These results indicated that 405-nm LED treatment effectively controlled S. flexneri contamination of foods and food contact surfaces and that the bacterial inactivation may be the result of damage to multiple cellular components. These findings highlight the potential of LED technology in controlling S. flexneri during food processing, storage, and preparation.


Assuntos
Microbiologia de Alimentos , Shigella flexneri , Contagem de Colônia Microbiana , Manipulação de Alimentos , Humanos , Aço Inoxidável
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