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1.
PLoS One ; 15(8): e0237262, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32760129

RESUMO

The factors that influence the diversity and composition of raw milk and fecal microbiota in healthy commercial dairy herds are not fully understood, partially because the majority of metataxonomic studies involve experimental farms and/or single factors. We analyzed the raw milk and fecal microbiota of 100 healthy cows from 10 commercial alpine farms from the Province of Trento, Italy, using metataxonomics and applied statistical modelling to investigate which extrinsic and intrinsic parameters (e.g. herd, diet and milk characteristics) correlated with microbiota richness and composition in these relatively small traditional farms. We confirmed that Firmicutes, Ruminococcaceae and Lachnospiraceae families dominated the fecal and milk samples of these dairy cows, but in addition, we found an association between the number of observed OTUs and Shannon entropy on each farm that indicates higher microbiota richness is associated with increased microbiota stability. Modelling showed that herd was the most significant factor affecting the variation in both milk and fecal microbiota composition. Furthermore, the most important predictors explaining the variation of microbiota richness were milk characteristics (i.e. percentage fat) and diet for milk and fecal samples, respectively. We discuss how high intra-herd variation could affect the development of treatments based on microbiota manipulation.


Assuntos
Bactérias/isolamento & purificação , Bovinos/microbiologia , Indústria de Laticínios , Fezes/microbiologia , Leite/microbiologia , Ração Animal/análise , Animais , Bactérias/classificação , Dieta , Gorduras/análise , Feminino , Microbiota , Leite/química
2.
Int J Syst Evol Microbiol ; 70(8): 4774-4781, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32744986

RESUMO

Three strains of a Gram-stain-positive, catalase-negative, facultative anaerobic, and coccoid species were isolated from German bulk tank milk. Phylogenetic analyses based on the 16S rRNA gene sequences indicated that the three strains (WS4937T, WS4759 and WS5303) constitute an independent phylogenetic lineage within the family Aerococcaceae with Facklamia hominis CCUG 36813T (93.7-94.1 %) and Eremococcus coleocola M1831/95/2T (93.5 %) as most closely related type species. The unclassified strains demonstrated variable growth with 6.5 % (w/v) NaCl and tolerated pH 6.5-9.5. Growth was observed from 12 to 39 °C. Their cell-wall peptidoglycan belongs to the A1α type (l-Lys-direct) consisting of alanine, glutamic acid and lysine. The predominant fatty acids were C16 : 1 ω9c, C16 : 0 and C18 : 1 ω9c and in the polar lipids profile three glycolipids, a phospholipid, phosphatidylglycerol, phosphoglycolipid and diphosphatidylglycerol were found. The G+C content of strain WS4937T was 37.4 mol% with a genome size of ~3.0 Mb. Based on phylogenetic, phylogenomic and biochemical characterizations, the isolates can be demarcated from all other genera of the family Aerococcaceae and, therefore, the novel genus Fundicoccus gen. nov. is proposed. The type species of the novel genus is Fundicoccus ignavus gen. nov., sp. nov. WS4937T (=DSM 109652T=LMG 31441T).


Assuntos
Aerococcaceae/classificação , Leite/microbiologia , Filogenia , Aerococcaceae/isolamento & purificação , Animais , Técnicas de Tipagem Bacteriana , Composição de Bases , DNA Bacteriano/genética , Ácidos Graxos/química , Glicolipídeos/química , Peptidoglicano/química , Fosfolipídeos/química , RNA Ribossômico 16S/genética , Análise de Sequência de DNA
3.
Food Chem ; 333: 127418, 2020 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-32653680

RESUMO

Fermented camel milk possesses a weak (liquid-like) gel structure. We aimed to 1) investigate the characteristics, bioactivities and rheological properties of the exopolysaccharide (EPS) produced by Lactococcus garvieae-C47 (exopolysaccharide-C47 product), a potential probiotic bacterium, on milk extracted from camels and 2) examine the rheological properties of the fermented camel milk produced by L. garvieae-C47. Exopolysaccharide-C47 product (molecular weight: 7.3 × 106 Da) was composed of the following monosaccharides: glucose (82.51%), arabinose (5.32%) and xylose (12.17%). The antioxidant, antitumor and α-amylase inhibitory activities of exopolysaccharide-C47 product reached up to 67.52, 59.35 and 91.0%, respectively. The apparent viscosity of exopolysaccharide-C47 product decreased with the increase in shear rate and declined by increasing the temperature up to 50 °C. The rheological properties of exopolysaccharide-C47 product are influenced by the salt type and pH value. The exopolysaccharide product produced by L. garvieae C47 possesses valuable health benefits and has the ability to improve the weak structure of fermented camel milk.


Assuntos
Fermentação , Lactococcus/metabolismo , Leite/microbiologia , Polissacarídeos Bacterianos/química , Polissacarídeos Bacterianos/farmacologia , Probióticos/metabolismo , Reologia , Animais , Antineoplásicos/química , Antineoplásicos/metabolismo , Antineoplásicos/farmacologia , Antioxidantes/química , Antioxidantes/metabolismo , Antioxidantes/farmacologia , Camelus , Inibidores Enzimáticos/química , Inibidores Enzimáticos/metabolismo , Inibidores Enzimáticos/farmacologia , Humanos , Peso Molecular , Polissacarídeos Bacterianos/biossíntese , Viscosidade , alfa-Amilases/antagonistas & inibidores
4.
Food Chem ; 332: 127398, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-32610260

RESUMO

Herein, a label-free and dual-readout immunochromatographic test strip (ITS) for the sensitive detection of Escherichia coli (E. coli) O157:H7 by taking advantages of the strong capture ability of Fe3O4@CuS nanostructures (NSs) towards bacteria and their ultrahigh photothermal effects (PTEs) was reported. Especially, without the customarily antibody (Ab)-labeled probe, Fe3O4@CuS NSs could be adsorbed onto the surfaces of bacteria to form Fe3O4@CuS-bacteria conjugates and then trapped by immobilized Abs on the test line (T-line), forming a characteristic yellow band. After direct immunoreactions, the PTEs of Fe3O4@CuS NSs endowed T-line to be irradiated by an 808 nm infrared light, obtaining satisfactory sensitivity and accuracy. Under optimal conditions, E. coli O157:H7, as low as 103 and 102 CFU/mL, could be monitored in colorimetric and photothermal modes. Additionally, E. coli O157:H7 was successfully detected in beef, chicken, milk and honey samples by this proposed platform with a recovery of 80-120%.


Assuntos
Cromatografia de Afinidade/métodos , Cobre/química , Escherichia coli O157/isolamento & purificação , Compostos Férricos/química , Microbiologia de Alimentos/métodos , Animais , Anticorpos Monoclonais/imunologia , Bovinos , Galinhas/microbiologia , Cromatografia de Afinidade/instrumentação , Escherichia coli O157/imunologia , Microbiologia de Alimentos/instrumentação , Mel/microbiologia , Limite de Detecção , Leite/microbiologia , Fitas Reagentes/química , Carne Vermelha/microbiologia
5.
Food Chem ; 332: 127420, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-32622191

RESUMO

The outbreaks of Cronobacter sakazakii, Salmonella spp, and Bacillus cereus in powdered foods have been increasing in worldwide. However, an effective method to pasteurize powdered foods before consumption remains lacking. A prototype Intense Pulsed Light (IPL) system was developed to disinfect powdered foods under different IPL and environmental conditions. Synergistic effect of IPL and TiO2 photocatalysis on microbial inactivation was studied. The results show that high energy intensity of each pulse, high peak intensity, and short pulsed duration contributed to a high microbe inactivation. With TiO2 photocatalysis, one additional log10 reduction was achieved, bringing the total log reduction to 4.71 ± 0.07 (C. sakazakii), 3.49 ± 0.01 (E. faecium), and 2.52 ± 0.10 (B. cereus) in non-fat dry milk, and 5.42 ± 0.10 (C. sakazakii), 4.95 ± 0.24 (E. faecium), 2.80 ± 0.23 (B. cereus) in wheat flour. IPL treatment combined with the TiO2 photocatalysis exhibits a strong potential to reduce the energy consumption in improving the safety of powdered foods.


Assuntos
Cronobacter sakazakii/efeitos da radiação , Cronobacter/efeitos da radiação , Farinha/microbiologia , Conservação de Alimentos/métodos , Viabilidade Microbiana/efeitos da radiação , Leite/microbiologia , Triticum/microbiologia , Animais , Bacillus cereus/crescimento & desenvolvimento , Bacillus cereus/efeitos da radiação , Cronobacter/crescimento & desenvolvimento , Microbiologia de Alimentos , Conservação de Alimentos/instrumentação , Luz , Pós/química , Salmonella/crescimento & desenvolvimento , Salmonella/efeitos da radiação
6.
Int J Food Microbiol ; 329: 108690, 2020 Sep 16.
Artigo em Inglês | MEDLINE | ID: mdl-32497790

RESUMO

Pecorino di Farindola is a typical cheese produced in the area surrounding the village of Farindola, located in the Abruzzo Region (central Italy), unique among Italian cheese because only raw ewe milk and pig rennet are used for its production. In the literature it is well documented that raw milk is able to support the growth of pathogenic microorganisms such as Listeria monocytogenes. Predictive microbiology can be useful in order to predict growth-death kinetics of pathogenic bacteria, on the basis of known environmental conditions. Aim of this study was to compare predictions obtained from a model, originally designed to predict the kinetics of L. monocytogenes in the dynamic growth-death environment of drying fresh sausage, with the results of challenge tests performed during the ripening of Pecorino di Farindola produced from artificially contaminated raw ewe milk. A challenge test was carried out using ewe raw milk inoculated with L. monocytogenes, in order to produce Pecorino di Farindola cheese stored at 18 °C for 149 days of ripening. During the ripening period, pH and aw values decreased in all samples analysed; lactic acid bacteria become the prevailing microbial population, while for L. monocytogenes a period of stability (neither growth nor death) followed the initial situation. The growth inhibition and the following inactivation may mostly be due to competition with the autochthonous microbiota and to the reduction of water activity. Mathematical modelling was used in order to predict microbial kinetics in the dynamic ripening environment, joining growth and death patterns in a continuous way, and including the highly uncertain growth/no growth range separating the two regions. The effect of lactic acid bacteria on the growth of pathogens was also included. Predicted microbial kinetics were satisfactory, as confirmed by the absence of statistically significant difference between observed and predicted values (p > 0.05). The present study proved, via challenge tests, that a dynamic growth/death model, previously used for a meat product, can be fruitfully used in cheese characterized by active competitive microbiota and progressive drying during ripening.


Assuntos
Queijo/microbiologia , Microbiologia de Alimentos , Listeria monocytogenes/crescimento & desenvolvimento , Modelos Biológicos , Animais , Itália , Cinética , Lactobacillales , Leite/microbiologia , Alimentos Crus/microbiologia
7.
Int J Food Microbiol ; 331: 108716, 2020 Oct 16.
Artigo em Inglês | MEDLINE | ID: mdl-32521375

RESUMO

Q fever is a common zoonotic disease with worldwide distribution. The causative agent of Q fever is Coxiella burnetii, a gram-negative and polymorphic rod bacterium. Sheep and goats are the primary reservoirs of this disease, although a variety of animal species can be infected. The main route of Q fever transmission from animals to humans is the inhalation of contaminated aerosols with C. burnetii. The bacterium is excreted in milk of infected animals and therefore; the consumption of unpasteurized milk and dairy products might be a route of coxiella burnetii transmission from animals to humans. The present study was conducted to determine the prevalence of C. burnetii in milk samples collected from sheep and goats in west Azerbaijan province, Iran. During 2018, a total number of 420 milk samples were collected from sheep (n = 210) and goats (n = 210) of different regions of the province. All milk samples were subjected to DNA extraction and examined by a highly and specific nested-PCR method. The results showed that 51 (12.1%) (95% CI: 9.3%-15.6%) examined samples [sheep; n = 16 (7.6%) and goat; n = 35 (16.6%)] were positive for C. burnetii. The prevalence of C. burnetii in goat milk samples was significantly higher than sheep milk samples (P < 0.05). The shedding of C. burnetii in milk was significantly higher in summer (25%) (P < 0.05, 95% CI: 17.7%-34%) than the other seasons. It was concluded that sheep and goat populations in west Azerbaijan play an important role in the epidemiology of Q fever.


Assuntos
Coxiella burnetii/genética , Doenças das Cabras/microbiologia , Leite/microbiologia , Febre Q/microbiologia , Doenças dos Ovinos/microbiologia , Zoonoses/microbiologia , Animais , Coxiella burnetii/isolamento & purificação , DNA Bacteriano/genética , DNA Bacteriano/isolamento & purificação , Doenças das Cabras/transmissão , Cabras , Humanos , Irã (Geográfico)/epidemiologia , Reação em Cadeia da Polimerase , Prevalência , Febre Q/epidemiologia , Ovinos , Doenças dos Ovinos/transmissão , Zoonoses/epidemiologia
8.
Int J Food Microbiol ; 331: 108691, 2020 Oct 16.
Artigo em Inglês | MEDLINE | ID: mdl-32534163

RESUMO

Currently, rapid, sensitive, and convenient visual detection methods for Staphylococcus aureus (S. aureus) are scarce. In this study, a novel detection method based on recombinase polymerase amplification (RPA) and polymer flocculation sedimentation (PFS) was developed. Twelve effective primer combinations derived from four forward primers F1, F2, F3, F4, and three reverse primers R1, R2, R3 targeting the nuc gene of S. aureus were designed and screened by a polymerase chain reaction and RPA methods. RPA reaction conditions, including temperature, time, and volume as well as PEG8000 and NaCl concentrations range, were optimized. Moreover, the specificity and sensitivity of the RPA-PFS assay were further analyzed. Finally, the potential use of the RPA-PFS assay was evaluated using artificially S. aureus contaminated food samples, including pork, beef, shrimp, fish, cheese, cabbage, leftover rice, egg, milk, and orange juice. Results showed that the SA5 (F2/R2) combination was the optimal primer candidate. The optimal temperature range, the shortest time and the minimal volume of RPA reaction were 40-42 °C, 10 min and 10 µL, respectively and the optimal PEG8000/NaCl concentrations were 0.2 g/mL and 2.5 M, respectively, for the adsorption between magnetic beads and RPA products. The RPA-PFS method could detect as little as 13 fg genomic DNA of S. aureus and was also specific for five target S. aureus as well as twenty-seven non-target foodborne bacteria. The limit of detection of RPA-PFS for S. aureus in artificially contaminated food samples was 38 CFU/mL (g). Besides, RPA-PFS has directly been judged by the naked eye and has totally taken less than 20 min. In short, the assay RPA-PFS developed in this study is a rapid, sensitive, and specific visual detection method for S. aureus.


Assuntos
Floculação , Microbiologia de Alimentos/métodos , Técnicas de Amplificação de Ácido Nucleico , Staphylococcus aureus/genética , Staphylococcus aureus/isolamento & purificação , Animais , Leite/microbiologia , Reação em Cadeia da Polimerase , Polímeros/química , Alimentos Marinhos/microbiologia , Sensibilidade e Especificidade , Infecções Estafilocócicas/prevenção & controle
9.
Int J Food Microbiol ; 330: 108688, 2020 Oct 02.
Artigo em Inglês | MEDLINE | ID: mdl-32497940

RESUMO

The impact of salt and fat intake on human health drives the consumer's attention towards dairy food with reduced salt and fat contents. How changes in salt and fat content modulate dairy LAB population and the associated proteolytic activities have been poorly studied. Here, non-starter LAB populations from 12 Parmigiano Reggiano (PR) cheeses (12-month ripened), clustered in low salt and fat content (LL-PR) and high salt and fat content (HH-PR) groups, were investigated and identified at specie-level with molecular assays. Lactobacillus rhamnosus was dominant in HH-PR samples, whereas Lactobacillus paracasei in LL-PR samples. (GTG)5 rep-PCR analysis discriminated 11 and 12 biotypes for L. rhamnosus and L. paracasei isolates, respectively. Screening for proteolytic activity identified L. rhamnosus strains more proteolytic than L. paracasei, and, within L. rhamnosus species, HH-PR strains were generally more proteolytic than LL-PR strains. Two L. rhamnosus representatives, namely strain 0503 from LL-PR and strain 2006 from HH-PR, were functionally characterized in cow milk fermentation assay. HH-PR strain 2006 overcame LL-PR strain 0503 in acidification performance, leading to a fermented milk with higher angiotensin I-converting enzyme inhibitory and antioxidant activities. L. rhamnosus 2006 was more prone to release VPP, while L. rhamnosus 0503 released higher amount of IPP. This study provides evidences that salt/fat content affects NSLAB cultivable fraction and the associated proteolytic ability resulting in a complex occurrence of bioactive peptides featuring health-promoting properties.


Assuntos
Anti-Hipertensivos/metabolismo , Queijo/microbiologia , Lactobacillus/isolamento & purificação , Peptídeos/metabolismo , Cloreto de Sódio/análise , Inibidores da Enzima Conversora de Angiotensina/metabolismo , Animais , Antioxidantes/metabolismo , Queijo/análise , Gorduras/análise , Fermentação , Lactobacillus/classificação , Lactobacillus/metabolismo , Leite/química , Leite/microbiologia
10.
Arch Microbiol ; 202(8): 2207-2219, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32524178

RESUMO

The objectives of this study were to isolate lactic acid bacteria (LAB) from a raw Moroccan camel milk collected after the incorporation of a specific Argane by-products diet, and to investigate their technological properties as well as their probiotic features. The molecular identification of the isolates indicated that they belong to Weissella confusa, Weissella cibaria or Enterococcus durans species. Our results revealed that the tested isolates have a fast acidifying ability (values ranging between 0.045 ± 0.01 to 0.93 ± 0.01 after only 4 h incubation), important proteolysis, autolysis, lipolytic activities and an important diacetyl and exopolysaccharides production. All these isolates demonstrated a high tolerance to gastrointestinal conditions, namely to gastric simulated juice (survival rate ranged between 75.05 ± 7.88 and 85.55 ± 1.77%) and to bile salts (survival rate between 42.79 ± 1.11 and 82.75 ± 1.01%). The autoaggregation, hydrophobicity and antioxidant activity mean values of the isolates were 13.26-41.16%, 13.23-54.47% and 47.57-63.31%, respectively. Importantly, LAB cultures exhibited antibacterial activity against Gram-negative and Gram-positive pathogenic bacteria and none of the tested isolates presented antibiotic resistance, haemolytic or DNase activities. This study revealed interesting properties for LAB isolated and supported their utilization as autochthone starters for camel milk fermentation that represent a challenge process. These results presented as well the probiotic potential for a possible human consumption.


Assuntos
Camelus , Enterococcus/fisiologia , Lactobacillales/fisiologia , Leite/microbiologia , Weissella/fisiologia , Animais , Antibiose , Enterococcus/classificação , Enterococcus/isolamento & purificação , Fermentação , Lactobacillales/isolamento & purificação , Probióticos/metabolismo , Alimentos Crus/microbiologia , Weissella/classificação , Weissella/isolamento & purificação
11.
Int J Syst Evol Microbiol ; 70(7): 4105-4110, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32589570

RESUMO

A polyphasic taxonomic study was performed on an unidentified Arcanobacterium-like Gram-stain-positive bacterium designated strain C605018/01/1T isolated from a milk sample collected from the udder of a cow at post mortem. Comparative 16S rRNA gene sequencing showed that the bacterium belonged to the genus Arcanobacterium and was most closely related to the type strain of Arcanobacterium pluranimalium (99.76 %); sequence similarities to all other Arcanobacterium species were below 97 %. The wet-lab DNA-DNA hybridization values among strain C605018/01/1T and A. pluranimalium DSM 13483ᵀ were low, 16.9 % (reciprocal, 49.8 %). Pertaining to the whole genome sequence with a total length of 2.02 Mb and 1654 protein counts, the novel strain C605018/01/01T displayed a G+C content of 51.6 % mol%. The presence of the major menaquinone MK-9(H4) supported the affiliation of this strain to the genus Arcanobacterium. The polar lipid profile consisted of the major components diphosphatidylglycerol, phosphatidylcholine, phosphatidylinositol, phosphatidylinositol-mannoside and unidentified glycolipid and aminophospholipids. Based on these results it is proposed that strain C605018/01/1T should be classified as representing a novel species, Arcanbacterium bovis sp. nov. The type strain C605018/01/1T (CCUG 45425T=DSM 107286T=BCCM/LMG 30783T).


Assuntos
Arcanobacterium/classificação , Mastite Bovina/microbiologia , Leite/microbiologia , Filogenia , Animais , Arcanobacterium/isolamento & purificação , Técnicas de Tipagem Bacteriana , Composição de Bases , Bovinos , DNA Bacteriano/genética , Ácidos Graxos/química , Feminino , Glicolipídeos/química , Hibridização de Ácido Nucleico , Fosfolipídeos/química , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Vitamina K 2/análogos & derivados , Vitamina K 2/química , Sequenciamento Completo do Genoma
12.
PLoS One ; 15(5): e0233132, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32413097

RESUMO

The Streptococcus bovis/Streptococcus equinus complex (SBSEC) and possibly Streptococcus infantarius subsp. infantarius (Sii) are associated with human and animal diseases. Sii predominate in spontaneously fermented milk products with unknown public health effects. Sii/SBSEC prevalence data from West Africa in correlation with milk transformation practices are limited. Northern Côte d'Ivoire served as study area due to its importance in milk production and consumption and to link a wider Sudano-Sahelian pastoral zone of cross-border trade. We aimed to describe the cow milk value chain and determine Sii/SBSEC prevalence with a cross-sectional study. Dairy production practices were described as non-compliant with basic hygiene standards. The system is influenced by secular sociocultural practices and environmental conditions affecting product properties. Phenotypic and molecular analyses identified SBSEC in 27/43 (62.8%) fermented and 26/67 (38.8%) unfermented milk samples. Stratified by collection stage, fermented milk at producer and vendor levels featured highest SBSEC prevalence of 71.4% and 63.6%, respectively. Sii with 62.8% and 38.8% as well as Streptococcus gallolyticus subsp. macedonicus with 7.0% and 7.5% were the predominant SBSEC species identified among fermented and unfermented milk samples, respectively. The population structure of Sii/SBSEC isolates seems to reflect evolving novel dairy-adapted, non-adapted and potentially pathogenic lineages. Northern Côte d'Ivoire was confirmed as area with high Sii presence in dairy products. The observed production practices and the high diversity of Sii/SBSEC supports in-depth investigations on Sii ecology niche, product safety and related technology in the dairy value chain potentially affecting large population groups across sub-Saharan Africa.


Assuntos
Produtos Fermentados do Leite/microbiologia , Leite/microbiologia , Streptococcus bovis/isolamento & purificação , Animais , Bovinos , Costa do Marfim , Estudos Transversais , Feminino , Microbiologia de Alimentos , Humanos , Filogenia , Streptococcus/genética , Streptococcus/isolamento & purificação , Streptococcus bovis/genética , Streptococcus gallolyticus/genética , Streptococcus gallolyticus/isolamento & purificação
13.
Food Chem ; 327: 126945, 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-32447131

RESUMO

This paper described a high-performance molecular test for the detection of Mycobacterium bovis (M. bovis) based on digital loop-mediated isothermal amplification (dLAMP). M. bovis is a persistent pathogen that causes zoonotic tuberculosis and can infect both animals and human beings. The detection of M. bovis in milk samples is critical for effective control and prevention of zoonotic diseases but there lacks effective and sensitive methods. Here, we developed a convenient and low-cost system for M. bovis detection in milk, which incorporated automated DNA extraction and dLAMP by interfacial emulsification technique. Versus real-time PCR, dLAMP provides higher accuracy and sensitivity for direct M. bovis detection in milk, offering a limit of detection of 14 CFU/mL within 2 h. The dLAMP system can become a powerful platform for the detection of pathogens in complex samples and provide more reliable guidance for food safety testing, epidemiological research and clinical diagnosis.


Assuntos
Leite/microbiologia , Mycobacterium bovis/isolamento & purificação , Animais , Técnicas de Amplificação de Ácido Nucleico , Reação em Cadeia da Polimerase em Tempo Real
14.
Anim Sci J ; 91(1): e13375, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32363702

RESUMO

This research aims to investigate the factors affecting Thai dairy farmers' intention to use ultraviolet C technology (UV-C) to reduce the number of microorganisms in raw milk. The researcher applied the innovation and diffusion theory (IDT) and the technology acceptance model 2 (TAM2) to evaluate dairy farmer's intention. The 477 dairy farmers in the central part of Thailand were interviewed using questionnaires. The collected data were analyzed using multinomial logistic regression (MLR). It was found that the intention to adopt UV-C can accurately predict the factors affecting the intention to use the technology based on the intention levels to create diffusion and promote acceptance. To increase the diffusion and acceptance of UV-C, the perceived usefulness to increase the milk price was the major influenced factor to promote technology acceptance. Providing facilities for maintenance, the use of this innovation and reporting news about the benefits of new technology to create positive attitudes and confidence lead to the spread of technology driven by early adopters. The technology developers should consider and design technology compatible with existing systems. However, the collaboration of all related parties is also needed to encourage Thai dairy farmers to try the new technology and observe the actual results.


Assuntos
Indústria de Laticínios/métodos , Qualidade dos Alimentos , Leite/microbiologia , Raios Ultravioleta , Animais , Bovinos , Análise de Dados , Feminino , Modelos Logísticos , Inquéritos e Questionários
15.
BMC Public Health ; 20(1): 742, 2020 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-32434499

RESUMO

BACKGROUND: Milk is a nutrient-rich food that makes an important contribution to diets in several Low and Middle Income Countries such as Senegal. Milk can also harbour several pathogenic microorganisms. As in other low and middle income countries, the dairy industry in Senegal is growing, with an expansion of farms to meet rapidly growing demand in the cities. However, most of the production still happens in the informal sector, and little is known about consumption of milk and milk products, or knowledge, awareness and practices of actors in informal dairy supply chains. METHODS: We conducted structured focus group discussions with dairy farmers and milk processors in three selected regions (Dakar, Thies and Fatick) in Senegal to investigate the consumption practices, awareness of milk borne hazards, and practices relevant to the risk of milk contamination to gain a deeper understanding of drivers of milk-borne diseases. Data on the consumption of milk and milk products were also collected using a closed questionnaire. RESULTS: Results indicate that milk is an important part of the diet in the study regionsand raw milk consumption is very common. The most common milk product consumed was fermented milk. Awareness of milk borne hazards was limited. Several farmers and processors reported risky practices, despite being aware of better practices, due to cultural beliefs. In households, children, pregnant women and older people were prioritised when milk and milk products were distributed. Dairy farmers and milk processors were more concerned with the lack of food for animals, low production and seasonality of production than the safety of the milk and milk products. CONCLUSIONS: Lack of awareness of milk borne infections and some traditional practices put milk and milk product consumers in the study area at high risk of milk borne diseases.. Prioritising certain sub population at households (Pregnant women and children) makes then vulnerable to milk-borne hazards. It will be challenging to change the risky practices as they are motivated by cultural beliefs hence the best strategy to promote milk safety will be to encourage the boiling of milk by consumers.


Assuntos
Cultura , Indústria de Laticínios , Inocuidade dos Alimentos , Doenças Transmitidas por Alimentos , Conhecimentos, Atitudes e Prática em Saúde , Leite/microbiologia , Pasteurização , Adolescente , Adulto , Idoso , Animais , Conscientização , Bovinos , Criança , Características da Família , Fazendeiros , Feminino , Doenças Transmitidas por Alimentos/etiologia , Doenças Transmitidas por Alimentos/prevenção & controle , Humanos , Masculino , Glândulas Mamárias Animais , Gravidez , Senegal , Inquéritos e Questionários , Adulto Jovem
16.
PLoS One ; 15(5): e0233413, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32463823

RESUMO

The use of veterinary antibiotics is largely unregulated in low-income countries. Consequently, food producers rarely observe drug withdrawal periods, contributing to drug residues in food products. Drug residues in milk can cause immunogenic reactions in people, and selectively favor antibiotic-resistant bacteria in unpasteurized products. We quantified the prevalence of antibiotic residues in pasteurized and unpasteurized milk, and antibiotic-resistant bacteria from unpasteurized milk sold within Kibera, an informal settlement in Nairobi, Kenya. Ninety-five milk samples (74 pasteurized and 21 unpasteurized) were collected from shops, street vendors or vending machines, and tested for the presence of ß-lactam and tetracycline residues using IDEXX SNAP kits. MacConkey agar without- and with antibiotics (ampicillin, 32 µg/ml; tetracycline, 16 µg/ml) was used to enumerate presumptive E. coli based on colony morphology (colony forming units per ml, CFU/ml). ß-lactam and tetracycline residues were found in 7.4% and 3.2% of all milk samples, respectively. Residues were more likely to be present in unpasteurized milk samples (5/21, 23.8%) compared to pasteurized samples (5/75, 6.8%); P = 0.039. Two thirds of unpasteurized samples (14/21, 66.7%) contained detectable numbers of presumptive E. coli (mean 3.5 Log10 CFU/ml) and of these, 92.8% (13/14) were positive for ampicillin- (mean 3.2 Log10 CFU/ml) and 50% (7/14) for tetracycline-resistant E. coli (mean 3.1 Log10 CFU/ml). We found no relationship between the presence of antibiotic residues and the presence of antibiotic-resistant E. coli in unpasteurized milk sold within Kibera (P > 0.2).


Assuntos
Antibacterianos/análise , Contaminação de Alimentos/análise , Leite , Animais , Bactérias , Resíduos de Drogas/análise , Farmacorresistência Bacteriana , Escherichia coli , Humanos , Quênia , Leite/química , Leite/microbiologia , Pasteurização/estatística & dados numéricos , Tetraciclina/análise , beta-Lactamas/análise
17.
PLoS Negl Trop Dis ; 14(4): e0008108, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32236091

RESUMO

Brucellosis is an important zoonotic disease globally, with particularly high burdens in pastoral settings. While the zoonotic transmission routes for Brucella spp. are well known, the relative importance of animal contact, food-handling and consumption practices can vary. Understanding the local epidemiology of human brucellosis is important for directing veterinary and public health interventions, as well as for informing clinical diagnostic decision making. We conducted a cross-sectional study in Ijara District Hospital, north-eastern Kenya. A total of 386 individuals seeking care and reporting symptoms of febrile illness were recruited in 2011. Samples were tested for the presence of Brucella spp. using a real-time PCR (RT-PCR) and results compared to those from the test for brucellosis used at Ijara District Hospital, the febrile Brucella plate agglutination test (FBAT). A questionnaire was administered to all participants and risk factors for brucellosis identified using logistic regression with an information theoretic (IT) approach and least absolute shrinkage and selection (LASSO). Sixty individuals were RT-PCR positive, resulting in a prevalence of probable brucellosis of 15.4% (95% CI 12.0-19.5). The IT and LASSO approaches both identified consuming purchased milk as strongly associated with elevated risk and boiling milk before consumption strongly associated with reduced risk. There was no evidence that livestock keepers were at different risk of brucellosis than non-livestock keepers. The FBAT had poor diagnostic performance when compared to RT-PCR, with an estimated sensitivity of 36.6% (95% CI 24.6-50.1) and specificity of 69.3% (95% CI 64.0-74.3). Brucellosis is an important cause of febrile illness in north-eastern Kenya. Promotion of pasteurisation of milk in the marketing chain and health messages encouraging the boiling of raw milk before consumption could be expected to lead to large reductions in the incidence of brucellosis in Ijara. This study supports the growing evidence that the FBAT performs very poorly in the diagnosis of brucellosis.


Assuntos
Brucella/genética , Brucella/isolamento & purificação , Brucelose/diagnóstico , Brucelose/epidemiologia , Brucelose/microbiologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Testes de Aglutinação , Animais , Criança , Estudos Transversais , Feminino , Humanos , Quênia/epidemiologia , Gado , Modelos Logísticos , Masculino , Pessoa de Meia-Idade , Leite/microbiologia , Prevalência , Reação em Cadeia da Polimerase em Tempo Real , Fatores de Risco , Inquéritos e Questionários , Adulto Jovem
18.
PLoS One ; 15(4): e0231810, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32315369

RESUMO

Campylobacter jejuni has caused several campylobacteriosis outbreaks via raw milk consumption. This study reports follow-up of a milk-borne campylobacteriosis outbreak that revealed persistent C. jejuni contamination of bulk tank milk for seven months or longer. Only the outbreak-causing strain, representing sequence type (ST) 883, was isolated from milk, although other C. jejuni STs were also isolated from the farm. We hypothesized that the outbreak strain harbors features that aid its environmental transmission or survival in milk. To identify such phenotypic features, the outbreak strain was characterized for survival in refrigerated raw milk and in aerobic broth culture by plate counting and for biofilm formation on microplates by crystal violet staining and quantification. Furthermore, whole-genome sequences were studied for such genotypic features. For comparison, we characterized isolates representing other STs from the same farm and an ST-883 isolate that persisted on another dairy farm, but was not isolated from bulk tank milk. With high inocula (105 CFU/ml), ST-883 strains survived in refrigerated raw milk longer (4-6 days) than the other strains (≤3 days), but the outbreak strain showed no outperformance among ST-883 strains. This suggests that ST-883 strains may share features that aid their survival in milk, but other mechanisms are required for persistence in milk. No correlation was observed between survival in refrigerated milk and aerotolerance. The outbreak strain formed a biofilm, offering a potential explanation for persistence in milk. Whether biofilm formation was affected by pTet-like genomic element and phase-variable genes encoding capsular methyltransferase and cytochrome C551 peroxidase warrants further study. This study suggests a phenotypic target candidate for interventions and genetic markers for the phenotype, which should be investigated further with the final aim of developing control strategies against C. jejuni infections.


Assuntos
Infecções por Campylobacter/epidemiologia , Campylobacter jejuni/isolamento & purificação , Microbiologia de Alimentos , Leite/microbiologia , Alimentos Crus/microbiologia , Animais , Campylobacter jejuni/genética , Bovinos , Surtos de Doenças , Fazendas , Fezes/microbiologia , Finlândia , Humanos
19.
J Dairy Sci ; 103(6): 5019-5029, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32278555

RESUMO

This study investigated the effects of Lactobacillus plantarum WW-fermented skim milk (FSM) on the physiques of rats fed a high-fat diet and the mechanism of lipid lowering. Sprague-Dawley rats were randomly divided into a normal diet group (A), a high-fat diet group (B), a skim milk diet group (C), and an L. plantarum WW FSM diet group (D). After 12-wk feeding, we found that treatment with L. plantarum WW FSM could significantly alleviate symptoms in the pathological group. Meanwhile, high-throughput sequencing analysis showed that L. plantarum WW FSM also had a certain regulatory effect on the intestinal microorganisms in rats, which can increase the number of lactic acid bacteria and Bacteroides in the intestine. More importantly, real-time quantitative PCR and Western blot analysis showed that the probiotic was also involved in the expression of genes related to fat metabolism, especially the PPARB and CEBPB genes. Our study supports the hypothesis that the WW strain of L. plantarum could be a potential probiotic to be used in functional foods to alter lipid metabolism and reduce cholesterol levels.


Assuntos
Produtos Fermentados do Leite/microbiologia , Dieta Hiperlipídica , Lactobacillus plantarum/metabolismo , Leite/microbiologia , Animais , Intestinos/microbiologia , Metabolismo dos Lipídeos , Masculino , Leite/metabolismo , Probióticos/metabolismo , Ratos , Ratos Sprague-Dawley
20.
J Dairy Sci ; 103(6): 4991-5002, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32307173

RESUMO

This study aims to characterize Bacillus subtilis complex group from raw, pasteurized, and packaged extended shelf-life (ESL) milk samples, to determine their biofilm potential and source-track the microbial contaminants to control their presence during processing. Isolates were characterized using multi-locus sequence typing (MLST) with 7 housekeeping genes. The primers used were designed from the coding regions with the highest number of polymorphic sites. The heat resistance profile indicated that all 12 isolates are psychrotolerant as well as thermophilic, with temperature ranges of 6°C to 55°C (B43, B44, B52, B54, B55, B56, B57), 6°C to 60°C (B46, B47, B48), and 15°C to 60°C (B49, B50). A general linear model 2-way repeated-measure ANOVA of the biofilm-forming potential of the isolates shows a statistically significant difference across the time of incubation (6, 12, 18, and 24 h). All isolates except 2 formed moderate to strong biofilms, with B44 having the most robust biofilm formation (3.14 ± 0.60). Scanning electron and confocal microscopy images reveal the strain specificity of the biofilm structure. The MLST analysis identified all isolates as belonging to either B. subtilis or Bacillus velezensis. All the isolates were novel sequence types (ST) when compared with the PubMLST database (https://pubmlst.org/) but showed relatedness to isolates in the raw milk that was processed. The closest ST are 96 for B. velezensis and 128 for B. subtilis, mostly isolated from soil. This study presents the significance of biofilms of thermophilic B. subtilis and B. velezensis and their possible perpetuation in the dairy processing plant. The information provided is a call for an innovative food contact surface or any other intervention that can minimize or prevent microbial adhesion in the processing plant, to prevent negative effects in ESL milk.


Assuntos
Bacillus subtilis/crescimento & desenvolvimento , Bacillus/crescimento & desenvolvimento , Biofilmes , Indústria de Laticínios , Leite/microbiologia , Animais , Bacillus/isolamento & purificação , Tipagem de Sequências Multilocus , Pasteurização , Esporos Bacterianos/isolamento & purificação
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