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1.
Food Microbiol ; 85: 103283, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31500718

RESUMO

Many countries use Escherichia coli and coliforms as indicators of sanitary quality of foods and have set limits for cheeses, including raw-milk cheeses. This paper reviewed the scientific literature for E. coli and coliform levels that are found in different types of raw milk, the fate of indicators during the manufacturing and ripening of different cheeses and the indicator levels that have been found in the finished cheeses. These studies from worldwide showed that E. coli and coliforms are found in different types of raw milk but usually at <100 CFU/ml or not found. Instances where raw milk contained indicator levels >1000 CFU/ml have mostly been attributed to unsanitary conditions/production. During cheese-making, indicators present in raw milk will often increase in numbers, but the levels decline as the acidity from lactose fermentation decreases the pH. Except for fresh cheeses that are not aged, indicator levels are further reduced by 2-3 log10 CFU/g or more, during the ripening process. As a result, indicator levels in finished cheeses are often low and within the limits of <10 or <100 CFU/g set by many countries. The cited studies also show that raw milk cheeses that are made with quality raw milk, under hygienic conditions and properly aged, should not contain high levels of indicator bacteria in the final product.


Assuntos
Bactérias/crescimento & desenvolvimento , Queijo/microbiologia , Microbiologia de Alimentos/métodos , Microbiologia de Alimentos/normas , Alimentos Crus/microbiologia , Animais , Queijo/normas , Contagem de Colônia Microbiana , Qualidade de Produtos para o Consumidor , Escherichia coli/crescimento & desenvolvimento , Contaminação de Alimentos/análise , Manipulação de Alimentos , Leite/microbiologia
3.
BMC Infect Dis ; 19(1): 949, 2019 Nov 08.
Artigo em Inglês | MEDLINE | ID: mdl-31703557

RESUMO

BACKGROUND: Enterohemorrhagic Escherichia coli (EHEC) is an important pathogen that causes diarrhea, hemorrhagic colitis, and hemolytic uremic syndrome (HUS). After an EHEC outbreak involving uncooked beef, serving raw beef liver dishes at restaurants was completely banned starting on July 1, 2012 in Japan. However, its long-term associations with the incidence rates of EHEC infections have never been assessed by formal interrupted time-series analysis (ITSA). METHODS: A retrospective cohort study to assess the impact of banning raw beef liver provision at restaurants was conducted. The weekly incidence of asymptomatic and symptomatic EHEC infections, the incidence of HUS, and deaths were extracted from the national reportable diseases database from January 2008 to December 2017. ITSA was conducted to evaluate the impact of banning raw beef liver from July 2012. To account for a potential simultaneous external effect, the additional regulation on raw beef red meat handling (implemented in May 2011) and the seasonality were also incorporated into the model. RESULTS: There were 32,179 asymptomatic and 21,250 symptomatic EHEC infections (including 717 HUS cases and 26 deaths) reported during the study period. During the pre-intervention period (before week 27, 2012), there were 0.45 asymptomatic EHEC infections per million-persons per week. The mean post-intervention asymptomatic EHEC infections were 0.51 per million-persons per week. ITSA revealed no baseline trend or change in the intercept and trend (0.002 infections per million-persons per week, 95% Confidence interval - 0.03-0.04, p = 0.93, 1.22, CI -1.96-4.39, p = 0.45, and - 0.006, CI -0.003-0.02, p = 0.68, respectively). For symptomatic EHEC infections, there were 0.30 cases per million per week during the pre-intervention period, and it became 0.33 cases per million per week after the intervention. Time series modeling again did not show a significant baseline trend or changes in the intercept and trend (0.0005, CI -0.02-0.02, p = 0.96, 0.69, CI -1.75-3.12, p = 0.58, and - 0.003, CI -0.02-0.01, p = 0.76, respectively). CONCLUSION: We did not find a statistically significant reduction in the overall incidence rates of both asymptomatic and symptomatic EHEC infections in Japan after implementing measures, including a ban on serving raw beef liver dishes in the restaurant industry.


Assuntos
Surtos de Doenças , Escherichia coli Êntero-Hemorrágica/isolamento & purificação , Infecções por Escherichia coli/epidemiologia , Análise de Séries Temporais Interrompida/métodos , Fígado/microbiologia , Alimentos Crus/microbiologia , Carne Vermelha/microbiologia , Restaurantes/legislação & jurisprudência , Animais , Doenças Assintomáticas/epidemiologia , Bovinos , Feminino , Microbiologia de Alimentos , Humanos , Incidência , Japão/epidemiologia , Masculino , Estudos Retrospectivos
4.
Enzyme Microb Technol ; 130: 109360, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31421723

RESUMO

Streptococcus uberis is a major mastitis-causing environmental pathogen, which rapid immunodetection has not been possible due to the absence of specific anti-Str. uberis antibodies. Recently, a specific antibody against the Str. uberis adhesion molecule (SUAM) has been designed. In the present study, the specificity and affinity of this antibody towards SUAM antigenic region SAPVYLGVSTE and Str. uberis cells are characterized, using experimental and in silico bioinformatic methods. The selectivity studies and bioinformatic analyses revealed high specificity of the antibody towards Str. uberis. The Kd value of SAPVYLGVSTE/anti-Str. uberis antibody complex was 27 ±â€¯6 nM, indicating the applicability of this antibody for the detection of Str. uberis. The anti-Str. uberis antibody was used as a specific biorecognition element of a biosensor for the detection of Str. uberis bacteria in phosphate buffer and in milk and these analyses took less than 20 min. The Str. uberis biosensor was also tested in the milk of cows suffering from mastitis and the obtained results were in good agreement with the conventional identification of this pathogen by microbiological plating.


Assuntos
Mastite Bovina/diagnóstico , Leite/microbiologia , Alimentos Crus/microbiologia , Infecções Estreptocócicas/veterinária , Streptococcus/isolamento & purificação , Animais , Anticorpos Antibacterianos/sangue , Afinidade de Anticorpos , Aderência Bacteriana , Técnicas Biossensoriais , Bovinos , Biologia Computacional , Feminino , Mastite Bovina/imunologia , Infecções Estreptocócicas/diagnóstico , Infecções Estreptocócicas/imunologia , Streptococcus/patogenicidade
5.
Food Microbiol ; 84: 103271, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31421780

RESUMO

Fresh produce causes most foodborne outbreaks in the USA, and it is also considered a hazardous food product in other areas of the world such as Europe. The outbreaks attributed to fresh produce increase the focus of producers on hygiene to minimize exposure to food hazards. The fresh produce industry has the urgent need to detect if there are production lots contaminated with pathogenic microorganisms before distribution. Although the industry is mostly using end-product testing for the detection of target microorganisms, previous studies have evaluated the suitability of different sampling points within the production line of a fresh-cut processing plant. In the present study, the centrifuge effluent water was assessed as an alternative sampling point to end-product testing. E. coli was selected as an index microorganism of the presence of pathogens. The presence of E. coli was assessed in centrifuge effluent water, and fresh-cut lettuce from a commercial fresh-cut produce processing line (n = 95). The rate of false positives and negatives, as well as the specificity, sensitivity, and efficiency of the alternative method were calculated. The mean population of E. coli in positive water samples was 0.86 log cfu/100 mL, while the mean population of E. coli in positive fresh-cut lettuce samples was 0.23 log cfu/g. The proportion of positive samples in centrifuge effluent water and lettuce was similar (≈20%), and most of the results in both matrices were coincident (81.1%). However, the alternative method was not reliable due to its low sensitivity, as only 47.6% of the lettuce samples positive for E. coli could be matched with positive water samples.


Assuntos
Escherichia coli O157/isolamento & purificação , Contaminação de Alimentos/análise , Microbiologia de Alimentos/métodos , Alface/microbiologia , Água/análise , Centrifugação , Contagem de Colônia Microbiana , Manipulação de Alimentos/métodos , Alimentos Crus/microbiologia
6.
Food Microbiol ; 83: 167-174, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31202408

RESUMO

S. Enteritidis and S. Typhimurium are typically linked to foodborne outbreaks. Phages have continued to expand in various food applications. In this study, microencapsulation is applied for enhancing the stability and efficacy of phages as bio-control agent. Microencapsulated phage cocktail kept in aluminium laminated foil bag (LF) at 4 °C showed the highest survivability with a titer loss of 0.5 log PFU/g after 12 weeks of storage. Titer loss of phage cocktail lysate >4 log PFU/mL was observed after 12 weeks, at 4 °C. Color change of microencapsulated phage cocktail kept in LF at 4 °C did not show any significant difference during storage, and water activity (free water content) at 0.13 was found in these conditions. In-vitro study, S. Enteritidis and S. Typhimurium were decreased 1.79 and 3.63 log CFU/mL, respectively at 37 °C. Whereas, 0.43 and 0.76 log CFU/mL, respectively were observed at 10 °C. In foods, S. Enteritidis and S. Typhimurium were decreased 0.57 and 1.78 log CFU/cm2, respectively in meat. Whereas, 0.86 and 1.2 log CFU/g, respectively were observed in sprout. Foods with/without microencapsulated phage cocktail showed non-significant differences in liking scores after 2 days of storage. Overall, microencapsulated phage cocktail suggests another alternative for phage-based biocontrol with improved stability and efficacy for food application.


Assuntos
Agentes de Controle Biológico , Contaminação de Alimentos/prevenção & controle , Armazenamento de Alimentos/métodos , Fagos de Salmonella/fisiologia , Salmonella enteritidis/virologia , Salmonella typhimurium/virologia , Composição de Medicamentos , Microbiologia de Alimentos/métodos , Carne/microbiologia , Alimentos Crus/microbiologia , Plântula/efeitos dos fármacos , Células-Tronco
7.
Food Microbiol ; 83: 200-210, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31202414

RESUMO

Fresh vegetables are important components of an everyday balanced diet making ready to-eat-salads (RTE) a commodity widely consumed. However, in the past few years these products have been linked with outbreaks of salmonellosis and listeriosis; thus the continuous investigation of their safety is an essential requirement. A total of 216 samples of ready-to-eat salads from the Cypriot market were analysed to determine the microbiological quality and safety, along with physicochemical attributes of the salads and identify possible correlations between them. The samples were randomly collected from four retail outlets and correspond to five different salad producing companies. Furthermore, the effects of season, salad producer and type of salad and/or their interactions with the tested parameters were investigated. The results revealed that the higher microbial load among seasons was observed in samples collected during spring. Escherichia coli was found in 11.57% of samples and 2.62% of isolates were found to be able to produce extended spectrum ß-lactamase (ESBL). All samples were found negative for Salmonella enterica, whereas Listeria monocytogenes was present in 3.70% of samples. Higher levels of spoilage bacteria (lactic acid bacteria and Pseudomonas spp.) were detected during winter and spring. Additionally, the %CO2 production was affected by the type of salad, while the interaction between producer and type of salad, affected total phenolic content and antioxidant activity of samples. A positive correlation of phenols and antioxidants with the presence of Staphylococcus spp., Pseudomonas spp., E. coli and Bacillus cereus was observed, suggesting that excessive handling increases microbial load and plant stress.


Assuntos
Carga Bacteriana , Contaminação de Alimentos/análise , Microbiologia de Alimentos , Alimentos Crus/microbiologia , Verduras/microbiologia , Antioxidantes/análise , Contagem de Colônia Microbiana , Qualidade de Produtos para o Consumidor , Chipre , Escherichia coli/isolamento & purificação , Fast Foods/microbiologia , Listeria monocytogenes/isolamento & purificação , Fenóis/análise , Estações do Ano
8.
Medicina (Kaunas) ; 55(3)2019 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-30897848

RESUMO

Background and Objectives: Salmonellosis is a major foodborne bacterial infection throughout the world. Epidemiological surveillance is one of the key factors to reduce the number of infections caused by this pathogen in both humans and animals. The first outcome measure was the prevalence of non-typhoid Salmonella (NTS) infections between 2000 and 2017 among the population of the predominantly agricultural and touristic Polish region of Warmia and Masuria (WaM). The second outcome measure was the comparison of the NTS hospitalization rate of all registered NTS cases, an investigation of the monthly reports of infections, and the exploration of the annual minimal and maximal NTS infection number in WaM in the above-mentioned time period. The last outcome was a comparison of the prevalence of NTS infections in the region and in its administrative districts by considering both rural and urban municipalities three years before and three years after the accession of Poland into the European Union (EU) in 2004. Materials and Methods: The total number of infections and hospitalizations in the 19 districts of the WaM voivodship in Poland was registered monthly between 2000⁻2017 by the Provincial Sanitary-Epidemiological Station in Olsztyn, Poland. Results: Between 2000 and 2017, the number of diagnosed salmonellosis cases decreased significantly in WaM; the decrease was higher in urban districts than in rural ones, and the ratio of hospitalizations and the total number of NTS cases increased significantly across all districts. The lowest number of cases was reported in the winter months and was stable from 2007, whereas the highest number was reported in the summer months with a higher tendency of outbreaks. Conclusion: The falling number of salmonellosis cases in 2000⁻2017 in WaM reflects the general trend in Poland and Europe. The decrease of NTS infections in WaM is related to the accession of Poland into the EU.


Assuntos
Infecções por Salmonella/epidemiologia , Infecções por Salmonella/terapia , Inquéritos e Questionários/estatística & dados numéricos , Surtos de Doenças/estatística & dados numéricos , União Europeia , Contaminação de Alimentos , Inocuidade dos Alimentos/métodos , Hospitalização/economia , Hospitalização/estatística & dados numéricos , Humanos , Higiene/economia , Polônia/epidemiologia , Prevalência , Alimentos Crus/microbiologia , Estudos Retrospectivos , População Rural/estatística & dados numéricos , Infecções por Salmonella/economia , Estações do Ano , Estatísticas não Paramétricas , Resultado do Tratamento , População Urbana/estatística & dados numéricos
9.
Zhonghua Liu Xing Bing Xue Za Zhi ; 40(3): 354-359, 2019 Mar 10.
Artigo em Chinês | MEDLINE | ID: mdl-30884618

RESUMO

Objective: To investigate the antimicrobial resistance and molecular epidemiology of foodborne Yersinia (Y.) enterocolitica in Pudong New District of Shanghai. Methods: Four kinds of raw food samples were collected in retail circulation sites in Pudong from 2012 to 2016. Cold enrichment method was used to isolate Y. enterocolitica and further detection of biotype, serotype, virulent genes, antimicrobial susceptibility of the isolates and pulsed field gel electrophoresis (PFGE) were conducted. Results: A total of 3 900 raw food samples were collected during this period, including poultry product (n=590), livestock product (n=1 074), aquatic product (n=1 488), vegetable (n=748), in which 111 (2.8%) were contaminated by Y. enterocolitica. The detection rates of Y. enterocolitica in poultry product samples (5.3%, 31/590) and livestock product samples (4.5%, 48/1 074) were higher than those in aquatic product samples (1.6%, 24/1 488) and vegetable samples (1.1%, 8/748). The predominant biotype was 1A (95.5%) and predominant serotype was O∶8 (42.3%). All the strains lacked ail, ystA, yadA and virF genes, which encoded pathogenic Y. enterocolitica. Seventy six (68.5%) strains harbored ystB gene, in which 35 (31.5%) belonged to 1A/O∶8/ystB pattern. Most strains were resistant to ampicillin (74.8%) and amoxicillin/clavulanic acid (70.3%), and non-sensitive rate to Cefoxitin was over 50.0%. No third generation cephalosporin or fluoroquinolone resistant strains were detected, but 38.7% (43/111) strains were multidrug resistant (MDR). Serotype O∶8 and O∶5 strains had 44 and 18 PFGE patterns, respectively. Conclusions: The main foodborne exposure sources of Y. enterocolitica in raw food were poultry and livestock products in Pudong New District. 1A/O∶8/ystB was the predominant pattern with potential pathogenicity despite lacks of typical pathogenic virulent genes. The antimicrobial resistant rates of Y. enterocolitica were at a low level, but MDR strains still existed. Molecular types of the isolates showed highly genetic diversity.


Assuntos
Farmacorresistência Bacteriana , Microbiologia de Alimentos , Alimentos Crus/microbiologia , Yersinia enterocolitica , Antibacterianos/farmacologia , Técnicas de Tipagem Bacteriana , China/epidemiologia , Humanos , Epidemiologia Molecular , Sorogrupo , Yersinia enterocolitica/classificação , Yersinia enterocolitica/efeitos dos fármacos , Yersinia enterocolitica/genética , Yersinia enterocolitica/isolamento & purificação
11.
Nutr. clín. diet. hosp ; 39(1): 162-168, 2019. ilus, tab, graf
Artigo em Espanhol | IBECS | ID: ibc-184202

RESUMO

Introducción: El Kebbe Naihe o kipi crudo es un producto cárneo que tiene como ingredientes la carne bovina u ovina molida y trigo burgol, condimentos y especias y se consume crudo. La carne es el vehículo de microorganismos que causan brotes de enfermedades, infecciones e intoxicaciones microbianas y resulta riesgosa su incorporación, dada la frecuencia con la que se pueden aislar bacterias patógenas a partir del producto crudo. El uso de diferentes sustancias controla el número de microorganismos en preparaciones alimenticias. Objetivos: Determinar el efecto del jugo de limón sobre los microorganismos presentes en el kipi crudo, analizar la aceptabilidad y satisfacción del kipi crudo con limón, y la preferencia del kipi crudo con limón respecto del kipi crudo sin limón. Metodología: Estudio de tipo descriptivo, correlacional y explicativo, y con un diseño en dos etapas, una etapa experimental- experimento puro y en otra etapa experimental-preexperimento. Resultados: Los análisis microbiológicos indicaron que en el momento de elaboración y a las 6, 12 y 24hs, el número de microorganismos fue menor en el kipi crudo tratado con limón, comparado con el que no recibió este tratamiento. Asimismo, el jugo de limón disminuyó el número de bacterias del kipi crudo a medida que el tiempo de exposición a este fue mayor. El kipi crudo con jugo de limón resultó ser más aceptado, satisfactorio y preferido por la población no árabe, en comparación con la población árabe. El kipi crudo es un producto apto para el consumo desde el punto de vista microbiológico si se consume antes de las 6hs posteriores a su elaboración, lo cual permite a la población árabe continuar consumiendo este plato sin el agregado de limón. Conclusión: Es posible, para quienes les resulta agradable el kipi crudo con limón, incrementar su inocuidad mediante el agregado de esta sustancia natural


Introduction: Kebbe Naihe or raw kipi is a meat-derived food, which has bovine or ovine ground meat and wheat burgol, condiments and spices as ingredients, and is consumed in raw state. Meat is the vehicle of microorganisms that cause diseases outbreaks, infections and microbial poisoning and its incorporation is risky given the frequency of isolation of pathogenic bacteria from raw products. The use of different substances controls the number of microorganisms in food preparations. Objectives: to determine the effect of lemon juice on the microorganisms present in raw kipi, to analyze the acceptability and satisfaction of raw kipi with lemon, and the preference of raw kipi with lemon compared to raw kipi without lemon. Methodology: Descriptive, correlational and explanatory type study, with a two-stage design, a pure experimental-experimental stage and pre-experiment in another stage. Results: The microbiological analysis indicated that at the time of elaboration and at 6, 12 and 24 hours, the number of microorganisms was lower in the raw kipi treated with lemon, compared to the one that did not receive this treatment. The lemon juice decreased the number of bacteria of the raw kipi at higher exposure times. The raw kipi with lemon juice resulted highly accepted, satisfactory and preferred by the non- Arabic population, compared to the Arabic group. Raw kipi is a suitable product for consumption from the microbiological point of view only if consumed before 6 hours after its preparation, which allows the Arabic population to continue consuming this plate without the addition of lemon. Conclusion: It is possible, for those who like the raw kipi with lemon, to increase its safety by adding lemon juice, a natural substance


Assuntos
Comportamento Alimentar/classificação , Citrus , Manipulação de Alimentos/métodos , Preferências Alimentares , Carne Vermelha/microbiologia , Microbiologia de Alimentos , Argentina , Alimentos Crus/microbiologia , Sucos de Frutas e Vegetais , Conservação de Alimentos
12.
mBio ; 9(6)2018 11 06.
Artigo em Inglês | MEDLINE | ID: mdl-30401772

RESUMO

Produce is increasingly recognized as a reservoir of human pathogens and transferable antibiotic resistance genes. This study aimed to explore methods to characterize the transferable resistome of bacteria associated with produce. Mixed salad, arugula, and cilantro purchased from supermarkets in Germany were analyzed by means of cultivation- and DNA-based methods. Before and after a nonselective enrichment step, tetracycline (TET)-resistant Escherichia coli were isolated and plasmids conferring TET resistance were captured by exogenous plasmid isolation. TET-resistant E. coli isolates, transconjugants, and total community DNA (TC-DNA) from the microbial fraction detached from leaves or after enrichment were analyzed for the presence of resistance genes, class 1 integrons, and various plasmids by real-time PCR and PCR-Southern blot hybridization. Real-time PCR primers were developed for IncI and IncF plasmids. TET-resistant E. coli isolated from arugula and cilantro carried IncF, IncI1, IncN, IncHI1, IncU, and IncX1 plasmids. Three isolates from cilantro were positive for IncN plasmids and bla CTX-M-1 From mixed salad and cilantro, IncF, IncI1, and IncP-1ß plasmids were captured exogenously. Importantly, whereas direct detection of IncI and IncF plasmids in TC-DNA failed, these plasmids became detectable in DNA extracted from enrichment cultures. This confirms that cultivation-independent DNA-based methods are not always sufficiently sensitive to detect the transferable resistome in the rare microbiome. In summary, this study showed that an impressive diversity of self-transmissible multiple resistance plasmids was detected in bacteria associated with produce that is consumed raw, and exogenous capturing into E. coli suggests that they could transfer to gut bacteria as well.IMPORTANCE Produce is one of the most popular food commodities. Unfortunately, leafy greens can be a reservoir of transferable antibiotic resistance genes. We found that IncF and IncI plasmids were the most prevalent plasmid types in E. coli isolates from produce. This study highlights the importance of the rare microbiome associated with produce as a source of antibiotic resistance genes that might escape cultivation-independent detection, yet may be transferred to human pathogens or commensals.


Assuntos
Farmacorresistência Bacteriana Múltipla/genética , Escherichia coli/genética , Plasmídeos/genética , Verduras/microbiologia , Coriandrum/microbiologia , Escherichia coli/efeitos dos fármacos , Transferência Genética Horizontal , Alemanha , Integrons/genética , Testes de Sensibilidade Microbiana , Reação em Cadeia da Polimerase , Alimentos Crus/microbiologia , Tetraciclina/farmacologia
13.
J Microbiol Methods ; 153: 66-73, 2018 10.
Artigo em Inglês | MEDLINE | ID: mdl-30195830

RESUMO

Counting colonies is usually used in microbiological analysis to assess if samples meet microbiological criteria. Although manual counting remains gold standard, the process is subjective, tedious, and time-consuming. Some developed automatic counting methods could save labors and time, but their results are easily affected by uneven illumination and reflection of visible light. To offer a method which counts colonies automatically and is robust to light, we constructed a convenient and cost-effective system to obtain images of colonies at near-infrared light, and proposed an automatic method to detect and count colonies by processing images. The colonies cultured by using raw cows' milk were used as identification objects. The developed system mainly consisted of a visible/near-infrared camera and a circular near-infrared illuminator. The automatic method proposed to count colonies includes four steps, i.e., eliminating noises outside agar plate, removing plate rim and wall, identifying and separating clustered or overlapped colonies, and counting colonies by using connected region labelling, distance transform, and watershed algorithms, etc. A user-friendly graphic user interface was also developed for the proposed method. The relative error and counting time of the automatic counting method were compared with those of manual counting. The results showed that the relative error of the automatic counting method was -7.4%~ + 8.3%, with average relative error of 0.2%, and the time used for counting colonies on each agar plate was 11-21 s, which was 15-75% of the time used in manual counting, depending on the numbers of colonies on agar plates. The proposed system and automatic counting method demonstrate promising performance in terms of precision, and they are robust and efficient in terms of labor- and time-savings.


Assuntos
Automação Laboratorial/métodos , Bactérias/crescimento & desenvolvimento , Contagem de Colônia Microbiana/instrumentação , Contagem de Colônia Microbiana/métodos , Raios Infravermelhos , Ágar , Algoritmos , Animais , Bovinos , Processamento de Imagem Assistida por Computador , Leite/microbiologia , Alimentos Crus/microbiologia
14.
J Zhejiang Univ Sci B ; 19(8): 630-642, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30070086

RESUMO

The storage and transportation of raw milk at low temperatures promote the growth of psychrotrophic bacteria and the production of thermo-stable enzymes, which pose great threats to the quality and shelf-life of dairy products. Though many studies have been carried out on the spoilage potential of psychrotrophic bacteria and the thermo-stabilities of the enzymes they produce, further detailed studies are needed to devise an effective strategy to avoid dairy spoilage. The purpose of this study was to explore the spoilage potential of psychrotrophic bacteria from Chinese raw milk samples at both room temperature (28 °C) and refrigerated temperature (7 °C). Species of Yersinia, Pseudomonas, Serratia, and Chryseobacterium showed high proteolytic activity. The highest proteolytic activity was shown by Yersinia intermedia followed by Pseudomonas fluorescens (d). Lipolytic activity was high in isolates of Acinetobacter, and the highest in Acinetobacter guillouiae. Certain isolates showed positive ß-galactosidase and phospholipase activity. Strains belonging to the same species sometimes showed markedly different phenotypic characteristics. Proteases and lipases produced by psychrotrophic bacteria retained activity after heat treatment at 70, 80, or 90 °C, and proteases appeared to be more heat-stable than lipases. For these reasons, thermo-stable spoilage enzymes produced by a high number of psychrotrophic bacterial isolates from raw milk are of major concern to the dairy industry. The results of this study provide valuable data about the spoilage potential of bacterial strains in raw milk and the thermal resistance of the enzymes they produce.


Assuntos
Bactérias/enzimologia , Laticínios , Endopeptidases/química , Leite/microbiologia , Alimentos Crus/microbiologia , Animais , Bactérias/genética , Proteínas de Bactérias/química , Biofilmes , Temperatura Baixa , Estabilidade Enzimática , Microbiologia de Alimentos , Temperatura Alta , Lipase/química , Peptídeo Hidrolases/química , Fosfolipases/química , RNA Ribossômico 16S/genética , beta-Galactosidase/química
15.
Int J Food Microbiol ; 284: 98-104, 2018 Nov 02.
Artigo em Inglês | MEDLINE | ID: mdl-30096596

RESUMO

Global widespread of extended-spectrum ß-lactamase (ESBL)-producing Enterobacteriaceae, especially Escherichia coli poses a greater threat in healthcare and community settings of humans. Raw meats from food animals colonized with ESBL producers may be one of important transmission routes for those bacteria in the community. This study investigated the presence of ESBL-producing E. coli in retail raw chicken and pork meats in Japan. ESBL producers were detected from the 59 of 150 (39.3%) chicken samples, but none were from all the 50 pork samples tested. The blaCTX-M-14 (17; 24.3%) was most frequently identified, followed by blaCTX-M-2 (16; 22.9%), blaSHV-12 (11; 15.7%), and blaCTX-M-55 (10; 14.3%) among a total of 70 ESBL-producing E. coli isolates from 59 chicken samples. The isolates with blaCTX-M-14 were often combined with phylogroup B1 (9/17) mainly composed of ST162 (7/9), and phylogroup F (5/17) with diverse STs. The blaCTX-M-14 was basically associated with the common elements ISEcp1 and ΔIS903 or IS903 in all 17 isolates. In 6 isolates, comprising 5 phylogroup B1-ST162 and a nontypeable-ST162 isolates, an IS26-truncated ISEcp1 was identified upstream of the blaCTX-M-14, and a fosA3 was further located downstream of ΔIS903. Furthermore, some mobile genetic elements mediating blaCTX-M-14 unique to raw chicken meat portions were identified. The blaCTX-M-2 gene was preceded by ISEcp1 or ISCR1 in 16 isolates, whereas the presence of Δorf3 downstream of blaCTX-M-2 was limited only in 6 isolates from Brazilian samples though they exhibited diverse phylogroups and STs. The blaCTX-M-55 and blaCTX-M-1 shared classical flanking structures, ISEcp1-blaCTX-M-orf477, although the length of spacer sequences between ISEcp1 and the start codon of blaCTX-M was 45 bp and 80 bp for blaCTX-M-55 and blaCTX-M-1, respectively. Among blaSHV-12-harboring isolates, ST38 was frequently detected (6/11) though their phylogroup distribution varied. In conclusion, besides transmission of bla gene-harboring E. coli lineages which have adaptability to both human and chicken, spread of mobile genetic elements associated with bla genes from E. coli lineages adapted to chicken to those adapted to human is highly suggested. Our results provide important information to gain a better understanding of the transmission risk of bla genes from retail chicken meats to human.


Assuntos
Antibacterianos/farmacologia , Galinhas/microbiologia , Escherichia coli/efeitos dos fármacos , Carne/microbiologia , Suínos/microbiologia , beta-Lactamases/genética , Animais , Brasil , Escherichia coli/genética , Escherichia coli/isolamento & purificação , Infecções por Escherichia coli/microbiologia , Infecções por Escherichia coli/transmissão , Humanos , Sequências Repetitivas Dispersas/genética , Japão , Prevalência , Alimentos Crus/microbiologia
16.
Int J Food Microbiol ; 285: 1-6, 2018 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-30005315

RESUMO

The genus Aeromonas includes human pathogenic bacteria frequently isolated from seafood, and the increased consumption of ready-to-eat seafood poses new food safety issues regarding the presence of potentially pathogenic Aeromonas spp. in stored products for raw consumption, such as retail sushi with a shelf life of up to three days. This study assessed 1) the growth kinetics of a mesophilic A. salmonicida strain during storage at 4 °C and 8 °C in a nigiri sushi model, and 2) the strain variability in growth at pH ranging from 3.5 to 10 for a subset of mesophilic Aeromonas strains previously isolated from sushi. Inoculated slices of raw salmon were compared with and without rice. A predictive model for A. hydrophila (ComBase Predictor) did not sufficiently predict growth of the tested strain under the intrinsic conditions of nigiri sushi or salmon at both temperatures. Refrigeration alone (4 °C) did not inhibit growth of A. salmonicida on salmon. Within the first 72 h, representing the typical shelf life of retail sushi products, we observed a 10-fold increase in the concentration of the inoculated strain (including a lag-phase of approximately 34 h). Contact with acidified rice, resulting in a pH drop in the salmon, was the reason for the decreased bacterial viability in the nigiri sushi samples. However, the effect of acidification decreased at 8 °C, resulting in a 2-fold increase in the growth rate and a reduced lag-phase compared to refrigeration. Variability in the ability to grow in different pH levels was observed between strains. The highest color formation rates, representing cellular respiration analyzed in a phenotypic microarray system, were observed between pH 5 and 8. A few strains, including the A. salmonicida strain applied in the nigiri sushi model, were able to grow at pH 4.5 (at optimal temperature). The results demonstrated that mesophilic Aeromonas spp. can represent a microbiological hazard in retail sushi products during cold storage. Rice acidification in combination with low storage temperature (≤4 °C) are prerequisites to prevent growth of potentially pathogenic Aeromonas species during the relatively short shelf life.


Assuntos
Aeromonas salmonicida/crescimento & desenvolvimento , Temperatura Baixa , Microbiologia de Alimentos , Armazenamento de Alimentos/normas , Alimentos Marinhos/microbiologia , Animais , Cinética , Modelos Teóricos , Alimentos Crus/microbiologia , Refrigeração
17.
Int J Food Microbiol ; 284: 120-127, 2018 Nov 02.
Artigo em Inglês | MEDLINE | ID: mdl-29887505

RESUMO

Raw milk may be a risk for public health if it is contaminated with zoonotic pathogens. To study the prevalence in unpasteurized milk from Swedish farms, bovine and small ruminant dairy farms were sampled. Since the sampling method and transport conditions may influence the outcome of analyses, efforts were made to optimize the methodology. Culturing of bacteria was done from in-line milk filters collected from the milk pipe at the point where it enters the milk bulk tank at the farms and this way of sampling was compared to sampling bulk tank milk (BTM) directly. Analysing milk filters were found to be superior to analysing BTM directly. Conditions for transport of milk filter samples were further improved by the addition of Cary Blair transport medium, which significantly increased the number of positive samples for pathogenic bacteria. The isolation of several foodborne pathogens from milk filters was demonstrated. The prevalence of samples with Staphylococcus aureus was 71% and 64%, and Listeria spp. 21% and 29% from dairy cow and goat/sheep farms, respectively. Campylobacter jejuni, Yersinia enterocolitica and verotoxigenic Escherichia coli (VTEC) O157 were detected in 9%, 2% and 2% of samples from bovine milk, respectively. We conclude that the choice of sampling method and sample handling influence the results of bacterial culturing. From the results of this study, we strongly recommend to sample in-line milk filters instead of BTM directly and to use Cary Blair medium during transport, especially if the samples are to be analysed for Campylobacter spp. and/or Listeria spp. The findings also show that unpasteurized milk from Swedish farms occasionally contain bacteria with zoonotic potential.


Assuntos
Campylobacter jejuni/isolamento & purificação , Escherichia coli O157/isolamento & purificação , Leite/microbiologia , Alimentos Crus/microbiologia , Staphylococcus aureus/isolamento & purificação , Yersinia enterocolitica/isolamento & purificação , Animais , Bovinos , Indústria de Laticínios/métodos , Feminino , Doenças Transmitidas por Alimentos/microbiologia , Cabras , Humanos , Pasteurização , Prevalência , Ovinos , Suécia
18.
Int J Med Microbiol ; 308(5): 539-544, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-29884330

RESUMO

Following a school ski-trip to Austria from 10 to 18/02/2017, nine of 25 participants of the group from Lower Saxony (Germany) developed gastroenteritis. The students and teachers (17-41 years) shared meals in a hotel. Active case finding revealed further cases among German school groups from North Rhine-Westphalia and Schleswig-Holstein, staying at the same hotel in February 2017. We conducted two retrospective cohort studies using self-administered questionnaires on clinical symptoms and food consumption. We defined a case as a trip participant in February 2017, staying at the aforementioned hotel and developing diarrhoea, vomiting or abdominal pain during or within ten days after the trip and/or who had a stool sample tested positive for STEC within four weeks after the trip. During the outbreak investigation, Austrian authorities detected that unlabeled raw cow milk delivered by a dairy farm had been offered at the hotel for breakfast during January and February 2017. Stool samples of participants, samples of milk served in the hotel and fecal samples of various animals kept at the milk-delivering farm were examined by culture and polymerase chain reaction. STEC isolates were typed using Pulsed-field Gel Electrophoresis (PFGE) and Whole-Genome Sequencing (WGS). All 25 participants from Lower Saxony completed the questionnaire on symptoms and milk consumption; 14 were cases (56%). Thirteen of 20 participants who had consumed cold milk fell ill (risk ratio (RR): 3.25; 95%-confidence interval (CI): 0.55-19.32). Of 159 trip participants from North Rhine-Westphalia, 81 completed the questionnaire (51%), 25 were cases (31%); RR for cold milk was 2.11 (CI: 0.89-5.03). The combined RR for cold milk in both groups was 2.49 (CI: 1.16-5.35). Shiga toxin 1a-gene and eaeA-gene positive STEC O103:H2 were detected in nine of 32 patients' stool samples and in two of 18 dairy farm cattle. Nine isolates from human stool samples and two isolates from cattle fecal samples yielded the same strain with an almost identical PFGE-pattern and WGS-profile. Microbiological and epidemiological evidence identified raw cow milk as the vehicle. Results may have been compromised by misclassification of cases due to a recall bias and mild symptoms. As a result of this outbreak investigation, the Austrian authorities enforced Austrian law in the hotel, to provide milk only when pasteurized. We recommend re-emphasizing the risk of raw milk consumption to providers.


Assuntos
Infecções por Escherichia coli/transmissão , Gastroenterite/microbiologia , Leite/microbiologia , Alimentos Crus/microbiologia , Escherichia coli Shiga Toxigênica/isolamento & purificação , Adolescente , Adulto , Animais , Áustria , Bovinos , Surtos de Doenças , Infecções por Escherichia coli/diagnóstico , Infecções por Escherichia coli/microbiologia , Microbiologia de Alimentos , Gastroenterite/diagnóstico , Alemanha , Humanos , Pasteurização , Estudos Retrospectivos , Toxina Shiga/genética , Escherichia coli Shiga Toxigênica/genética , Escherichia coli Shiga Toxigênica/patogenicidade , Inquéritos e Questionários , Adulto Jovem
19.
Epidemiol Infect ; 146(11): 1461-1467, 2018 08.
Artigo em Inglês | MEDLINE | ID: mdl-29880080

RESUMO

Foodborne non-typhoidal salmonellosis causes approximately 1 million illnesses annually in the USA. In April 2015, we investigated a multistate outbreak of 65 Salmonella Paratyphi B variant L(+) tartrate(+) infections associated with frozen raw tuna imported from Indonesia, which was consumed raw in sushi. Forty-six (92%) of 50 case-patients interviewed ate sushi during the week before illness onset, and 44 (98%) of 45 who specified ate sushi containing raw tuna. Two outbreak strains were isolated from the samples of frozen raw tuna. Traceback identified a single importer as a common source of tuna consumed by case-patients; this importer issued three voluntary recalls of tuna sourced from one Indonesian processor. Four Salmonella Weltevreden infections were also linked to this outbreak. Whole-genome sequencing was useful in establishing a link between Salmonella isolated from ill people and tuna. This outbreak highlights the continuing foodborne illness risk associated with raw seafood consumption, the importance of processing seafood in a manner that minimises contamination with pathogenic microorganisms and the continuing need to ensure imported foods are safe to eat. People at higher risk for foodborne illness should not consume undercooked animal products, such as raw seafood.


Assuntos
Surtos de Doenças , Microbiologia de Alimentos , Febre Paratifoide/etiologia , Alimentos Crus/microbiologia , Salmonella paratyphi B/isolamento & purificação , Atum/microbiologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Animais , Criança , Pré-Escolar , Eletroforese em Gel de Campo Pulsado , Feminino , Alimentos Congelados/efeitos adversos , Alimentos Congelados/microbiologia , Humanos , Indonésia , Lactente , Masculino , Pessoa de Meia-Idade , Febre Paratifoide/epidemiologia , Alimentos Crus/efeitos adversos , Salmonella paratyphi B/classificação , Alimentos Marinhos/efeitos adversos , Alimentos Marinhos/microbiologia , Sorotipagem , Inquéritos e Questionários , Estados Unidos/epidemiologia , Sequenciamento Completo do Genoma , Adulto Jovem
20.
Epidemiol Infect ; 146(11): 1397-1406, 2018 08.
Artigo em Inglês | MEDLINE | ID: mdl-29923474

RESUMO

The US Food Safety Modernization Act (FSMA) gives food safety regulators increased authority to require implementation of safety measures to reduce the contamination of produce. To evaluate the future impact of FSMA on food safety, a better understanding is needed regarding outbreaks attributed to the consumption of raw produce. Data reported to the US Centers for Disease Control and Prevention's Foodborne Disease Outbreak Surveillance System during 1998-2013 were analysed. During 1998-2013, there were 972 raw produce outbreaks reported resulting in 34 674 outbreak-associated illnesses, 2315 hospitalisations, and 72 deaths. Overall, the total number of foodborne outbreaks reported decreased by 38% during the study period and the number of raw produce outbreaks decreased 19% during the same period; however, the percentage of outbreaks attributed to raw produce among outbreaks with a food reported increased from 8% during 1998-2001 to 16% during 2010-2013. Raw produce outbreaks were most commonly attributed to vegetable row crops (38% of outbreaks), fruits (35%) and seeded vegetables (11%). The most common aetiologic agents identified were norovirus (54% of outbreaks), Salmonella enterica (21%) and Shiga toxin-producing Escherichia coli (10%). Food-handling errors were reported in 39% of outbreaks. The proportion of all foodborne outbreaks attributable to raw produce has been increasing. Evaluation of safety measures to address the contamination on farms, during processing and food preparation, should take into account the trends occurring before FSMA implementation.


Assuntos
Surtos de Doenças , Doenças Transmitidas por Alimentos/epidemiologia , Frutas/microbiologia , Verduras/microbiologia , /estatística & dados numéricos , Inocuidade dos Alimentos , Doenças Transmitidas por Alimentos/etiologia , Fungos , Humanos , Alimentos Crus/microbiologia , Estações do Ano , Plântula/microbiologia , Estados Unidos/epidemiologia , United States Food and Drug Administration/legislação & jurisprudência
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