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1.
Shokuhin Eiseigaku Zasshi ; 60(4): 88-95, 2019.
Artigo em Japonês | MEDLINE | ID: mdl-31474656

RESUMO

Microbial colony counts of concern of food products are one of the most important items in microbiological examinations. The distributions of colony counts per agar plate of food samples are considered to be reflected with microbial cell distributions in food homogenates. However, (i) the probabilistic distributions of the colony counts per agar plate at the dilution of counting and (ii) the relationship between the colony counts per plate and the number of agar plates for food samples have not been intensively studied so far. In this study, therefore, these two points were studied with raw food samples of raw minced beef and chicken and raw milk and microbial culture samples of Escherichia coli, Staphylococcus aureus, and Saccharomyces cerevisiae. Among four major probabilistic distributions, it was found that aerobic plate counts per plate of the foods were well described with negative binomial, Poisson, and normal distributions and that the colony counts per plate of microbial cultures were described well with binomial, Poisson, and normal distributions. The effect of the number of agar plates on the estimation of the mean of colony counts per plate of a sample was then studied with the data randomly resampled from the experimental data. The resampled data showed that with more number of plates the mean of counts fluctuated less and the coefficients of variation of colony counts per plate decreased further, which were coincident to the estimated by the central limit theory. Our study would provide useful information on the characteristics of colony counts per plate of food samples which are routinely examined.


Assuntos
Contagem de Colônia Microbiana , Contaminação de Alimentos/análise , Microbiologia de Alimentos , Ágar , Animais , Bovinos , Escherichia coli/isolamento & purificação , Carne/microbiologia , Leite/microbiologia , Saccharomyces cerevisiae/isolamento & purificação , Staphylococcus aureus/isolamento & purificação
2.
Shokuhin Eiseigaku Zasshi ; 60(3): 45-51, 2019.
Artigo em Japonês | MEDLINE | ID: mdl-31391410

RESUMO

This study aimed to survey the trend of antimicrobial resistance in Escherichia coli obtained from retail meat. We examined the susceptibilities of 1,115 E. coli isolates obtained from chicken, beef, pork, venison, and wild boar meat from 2011 to 2017 in Tokyo to 14 antimicrobials (ampicillin, cefotaxime (CTX), streptomycin, gentamicin, kanamycin, tetracycline (TC), chloramphenicol, nalidixic acid, ciprofloxacin, sulfamethoxazole-trimethoprim, fosfomycin, amikacin, imipenem, and meropenem). Of all the tested isolates, 18.7% (135/721) isolates from chicken, 77.0% (117/152) from beef, 46.6% (89/187) from pork, 100% (28/28) from venison, and 92.6% (25/27) from wild boar meat were susceptible to all tested antimicrobials. Furthermore, TC resistance was the most common, with rates as high as 56.7% (409/721) and 40.6% (76/187) in the isolates from chicken and pork, respectively. CTX resistance was detected in 4.9% (25/506) of the isolates from domestic chicken and 23.7% (51/215) of the isolates from imported chicken. Moreover, CTX resistance rate in isolates from domestic chicken was significantly lower in 2016 (0.9%, 1/111) and in 2017 (0.8%, 1/121) than in 2012 (10.6%, 17/161). In conclusion, E. coli isolates from retail meat were most commonly resistant to TC, and CTX resistance was higher in E. coli isolates from imported chicken than in E. coli isolates from domestic chicken.


Assuntos
Antibacterianos/farmacologia , Farmacorresistência Bacteriana , Escherichia coli/efeitos dos fármacos , Microbiologia de Alimentos , Carne/microbiologia , Animais , Bovinos , Galinhas , Cervos , Testes de Sensibilidade Microbiana , Prevalência , Suínos , Tóquio
3.
Int J Food Microbiol ; 304: 32-38, 2019 Sep 02.
Artigo em Inglês | MEDLINE | ID: mdl-31152975

RESUMO

The aim of this study was to determine the effects of marination liquids prepared with koruk juice and dried koruk pomace in terms of meat safety. In the study, marination liquids containing two different concentrations of koruk juice (25% and 50%) or dried koruk pomace (1% and 2%) were prepared separately with or without ingredients (1% salt and 0.1% thyme). Meat samples inoculated with two different levels (≅3 log and ≅6 log) of food-borne pathogens (S. Typhimurium, E. coli O157:H7 and L. monocytogenes) were marinated at 4 °C for different times (2, 24 and 48 h) and the effects of the treatment on target pathogens were determined. As a result of marinating process, the counts of S. Typhimurium, E. coli O157:H7 and L. monocytogenes inoculated at high levels (≅6 log) on meat samples were reduced in the range of 0.109-2.648 log CFU/g, 0.264-3.373 log CFU/g and 0.023-2.781 log CFU/g, respectively. The most effective treatment in reducing the counts of S. Typhimurium and E. coli O157:H7 was achieved by marination with ML1 (50% koruk juice + 50% water) for 48 h, while marination with ML2 (50% koruk juice + 50% water + 1% salt + 0.1% thyme) for 24 h was the most effective treatment for L. monocytogenes. When low inoculum levels were used (≅3 log), the counts of pathogens on meat samples were determined under detection limits after marination even for 2 h application. The results of sensory evaluation showed that the sample marinated with ML2 for 48 h was the most favored sample in terms of appearance, color, texture, taste and overall appreciation.


Assuntos
Antibacterianos/farmacologia , Antioxidantes/farmacologia , Escherichia coli O157/efeitos dos fármacos , Listeria monocytogenes/efeitos dos fármacos , Carne/microbiologia , Preparações de Plantas/farmacologia , Salmonella typhimurium/efeitos dos fármacos , Vitis/química , Contagem de Colônia Microbiana , Escherichia coli O157/crescimento & desenvolvimento , Manipulação de Alimentos/métodos , Microbiologia de Alimentos , Humanos , Listeria monocytogenes/crescimento & desenvolvimento , Salmonella typhimurium/crescimento & desenvolvimento
4.
Int J Food Microbiol ; 304: 49-57, 2019 Sep 02.
Artigo em Inglês | MEDLINE | ID: mdl-31154111

RESUMO

In this study, the antimicrobial resistance profiles of L. monocytogenes isolated from chicken meat in Fukuoka in 2017 were compared with the isolates of 2012. A total of 85 and 50 chicken meat samples, including different body parts, were collected from different supermarkets in Fukuoka in 2012 and 2017, respectively. Detection, isolation, identification, and characterization of L. monocytogenes were performed according to the conventional methods. Forty-five among 85 samples (53%) were positive for L. monocytogenes in 2012, while 12 among 50 samples in 2017 (24%) tested positive. One hundred fifty-three and 29 L. monocytogenes strains were isolated in 2012 and 2017, respectively. The serotypes of isolates in 2012 were 1/2a (21.5%), 1/2b (73.9%), 1/2c (1.5%), and 4b/4e (3.1%). In contrast, the 2017 isolates showed 1/2a (48.3%) and 1/2b (51.7%) serotypes. While all isolates in 2012 were positive for hlyA (listeriolysin O) in the PCR assay with hlyA primer set 7, only 17 hlyA positive isolates were seen in 2017. Moreover, 75 isolates with different ribotypes in 2012 and 29 isolates in 2017, respectively, were tested for antimicrobial susceptibility by broth microdilution for 18 different antimicrobial agents. Most of the 2012 and 2017 isolates displayed antimicrobial susceptibility. However, among the 2012 and 2017 isolates, 98.7% and 100% of the isolates were resistant to cefoxitin, 57.3% and 95.7% to fosfomycin, 72.0% and 82.6% to oxacillin, 8.0% and 17.4% to clindamycin, respectively. In addition, 2.7% of the isolates in 2012 were resistant to flomoxef and 4.3% of the isolates in 2017 to linezolid. Multidrug resistance (MDR) to 3 or more antimicrobials was observed in 35/75 (46.7%) isolates of 2012 and 19/23 (82.6%) in 2017. Detection of antimicrobial resistance (AMR) genes by PCR showed that the resistant isolates of 2012 were positive for mecA (96.3%) and ermC (83.3%), whereas the resistant isolates in 2017 screened positive for mecA (94.7%) and mefA (25.0%). Other cfxA, ermA, ermB, fosA, fosB, and fosC genes were absent in the PCR assay for any of the isolates. This study investigated for the first time the change in the L. monocytogenes contamination of chicken meat and antibiotic resistance of the isolated L. monocytogenes strains in Fukuoka, Japan, in the course of 5 years. Although the contamination rate of L. monocytogenes in 2017 was found to be lower than that in 2012, AMR of the isolates in 2017 was higher.


Assuntos
Antibacterianos/farmacologia , Galinhas/microbiologia , Farmacorresistência Bacteriana Múltipla/genética , Contaminação de Alimentos/análise , Listeria monocytogenes/efeitos dos fármacos , Listeria monocytogenes/genética , Carne/microbiologia , Animais , Microbiologia de Alimentos , Japão , Listeria monocytogenes/isolamento & purificação , Testes de Sensibilidade Microbiana , Reação em Cadeia da Polimerase , Sorogrupo
5.
BMC Infect Dis ; 19(1): 520, 2019 Jun 13.
Artigo em Inglês | MEDLINE | ID: mdl-31196008

RESUMO

BACKGROUND: Leprosy is is still considered a public health issue and in Colombia 7-10% of new cases are found in children, indicating both active transmission and social inequality. We hypothesized that circulating antibodies against Natural Octyl Disaccharide-Leprosy IDRI Diagnostic (NDO-LID) (a combination of Mycobacterium leprae antigens) could reveal the social and environmental aspects associated with higher frequencies of M. leprae infection among children and adolescents in Colombia. METHODS: An observational cross-sectional study was conducted involving sampling from 82 children and adolescents (younger than 18 years of age) who had household contact with index leprosy patients diagnosed in the last 5 years. Data were analyzed through bivariate analysis made by applying a Pearson x2 test for qualitative variables, while quantitative variables, depending on their distribution, were analyzed using either a Student's t-test or Mann-Whitney U test. Multivariate analysis was performed using a multiple regression and binomial logistic approach. RESULTS: A bivariate analysis demonstrated that antibody titers against NDO-LID were significantly greater in children and adolescents with a low socioeconomic status that had: lived in vulnerable areas of the UAChR shared region; eaten armadillo meat; exposure of over 10 years to an index case and; not received BCG immunization. Moreover, a multivariate analysis showed that residing in the UAChR region has a strong association with a greater possibility of M. leprae infection. CONCLUSIONS: M. leprae transmission persists among young Colombians, and this is associated with social and environmental conditions. An intensification of efforts to identify new leprosy cases in vulnerable and forgotten populations where M. leprae transmission continues therefore appears necessary.


Assuntos
Hanseníase/diagnóstico , Mycobacterium leprae/isolamento & purificação , Adolescente , Animais , Anticorpos Antibacterianos/sangue , Tatus , Vacina BCG/imunologia , Criança , Pré-Escolar , Colômbia/epidemiologia , Estudos Transversais , Ensaio de Imunoadsorção Enzimática , Feminino , Humanos , Lactente , Hanseníase/epidemiologia , Hanseníase/transmissão , Modelos Logísticos , Masculino , Carne/análise , Carne/microbiologia , Mycobacterium leprae/imunologia , Classe Social , Estatísticas não Paramétricas
6.
Vet Microbiol ; 233: 52-60, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31176413

RESUMO

The spread of extended-spectrum ß-lactamases (ESBLs) in Escherichia coli is a major public health issue and ESBL-producing bacteria are frequently reported in livestock. For the assessment of the role of the foodborne transmission pathway in Germany, detailed data on the prevalence and characteristics of isolates of food origin are necessary. The objective of this study was to describe the prevalence of cefotaxime resistant E. coli as well as ESBL/pAmpC-producing E. coli and their characteristics in foods in Germany. Out of 2256 food samples, the highest prevalence of cefotaxime resistant E. coli was observed in chicken meat (74.9%), followed by turkey meat (40.1%). Prevalence in beef, pork and minced meat was considerably lower (4.2-15.3%). Whereas 18.0% of the raw milk samples, collected at farm level were positive, this was true only for few cheese samples (1.3%). In one out of 399 vegetable samples a cefotaxime-resistant E. coli was isolated. ESBL resistance genes of the CTX-M-group (10.1% of all samples) were most frequently detected, followed by genes of the pAmpC (2.6%), SHV (2.0%) and TEM (0.8%) families. Distribution of ESBL/AmpC-encoding E. coli resistance genes and E. coli phylogroups was significantly different between the chicken related food samples and all other food items. Our study results reflect that consumers might get exposed to ESBL/pAmpC-producing E. coli through several food chains. These results together with those collected at primary production and in the human population in other studies will allow more detailed analysis of the foodborne pathways, considering transmission from livestock populations to food at retail and to consumers in Germany.


Assuntos
Proteínas de Bactérias/genética , Escherichia coli/genética , Microbiologia de Alimentos , Carne/microbiologia , beta-Lactamases/genética , Animais , Antibacterianos/farmacologia , Proteínas de Bactérias/biossíntese , Cefotaxima/farmacologia , Farmacorresistência Bacteriana , Escherichia coli/enzimologia , Infecções por Escherichia coli/transmissão , Infecções por Escherichia coli/veterinária , Proteínas de Escherichia coli/biossíntese , Proteínas de Escherichia coli/genética , Alemanha , Gado/microbiologia , Aves Domésticas/microbiologia , Prevalência , Carne Vermelha/microbiologia , Verduras/microbiologia , beta-Lactamases/biossíntese
7.
Int J Food Microbiol ; 300: 53-63, 2019 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-31048092

RESUMO

Microbial survival of heating and cross-contamination are the two transmission routes during food preparation in the consumers' kitchen that are relevant for QMRA (Quantitative Microbial Risk Assessment). The aim of the present study was to extend the limited amount of data on microbial survival during real-life preparation of meat and meat products and to obtain accessory temperature data that allow for a more general (product unspecific) approach. Therefore survival data were combined with extensive measurements of time- and location dependent temperature using an infrared camera for the surface and buttons for the inside of the product, supplemented with interpolation modelling. We investigated the survival of heating of Escherichia coli O111:H2 in beefsteak, hamburgers (beef and 50% beef 50% pork (HH)), meatballs (beef and HH) and crumbs (HH). For beefsteak, survival as a whole is dominated by the sides, giving a log reduction of 1-2 (rare), 3-4 (medium) and 6-7 (done). Limited measurements indicated that done preparation gave 5-6 log reduction for crumbs and at least 8-9 log for the other products. Medium preparation gave a higher reduction in hamburgers (2-4 log) than in meatballs (1-2 log) and in beef (3-4) than in HH (2-3) hamburgers. In general, our 'done' results give larger inactivation than found in literature, whereas 'rare' and 'medium' results are similar. The experiments resulted in two types of curves of D70/z-values, dependent on product, doneness and for beefsteaks sides vs. top/bottom. One type of curve agrees reasonably with literature D70/z estimates from isothermal temperature experiments, which supports using these estimates for home style cooking QMRA calculations. In case of the other type of curve, which is mainly found for (near) surface contamination in close contact with the pan, these literature estimates cannot be applied. We also applied a simplified approach, assuming thermal inactivation is dominated by the highest temperatures reached. The time duration of this highest temperature gives accessory D-values which prove to fit with isothermal temperature literature data, thus suggesting application of such data for QMRA is possible by this approach also, which is less labor intensive both in terms of measurements and modelling. In real life, variability in product properties and preparation styles is large. Further studies are needed to analyze the effect on survival, preferably focusing on determining the essential variables. More variation in heating time will allow for estimating D70/z point estimates rather than curves representing possible sets of D70/z-values.


Assuntos
Culinária , Microbiologia de Alimentos , Produtos da Carne/microbiologia , Carne/microbiologia , Temperatura Ambiente , Animais , Bovinos , Culinária/normas , Escherichia coli/fisiologia , Modelos Teóricos , Suínos
8.
Int J Food Microbiol ; 301: 27-33, 2019 Jul 16.
Artigo em Inglês | MEDLINE | ID: mdl-31082697

RESUMO

Pre-chilling leads to a temperature decline of the pre-rigor muscle of poultry carcasses, and a reduction of the initial bacterial load may occur. Both ultrasound (US) and slightly acidic electrolyzed water (SAEW) have been used alone in the meat industry for the manufacture of emulsions, pasteurization, and prevention of bacteria growth. However, the impact of the combination of these technologies during the pre-chilling of chicken carcasses has not been evaluated. In this study, breast chicken cylinders (CBCs) were pre-chilled for 10 min at 10 °C using SAEW and different US frequencies (25 and 130 kHz). The microbiological characteristics, lipid and protein oxidation, shear force, and anaerobic glycolysis were evaluated. The US + SAEW combination led to an effective reduction (P < 0.05) of enterobacteria, mesophilic bacteria, lactic acid bacteria, and psychrotrophic bacteria, while the lipid and protein oxidation, shear force, anaerobic glycolysis, and muscle structure were not affected (P > 0.05). Therefore, the combination of these technologies may be promising in the pre-chilling stage of chicken carcasses.


Assuntos
Ácidos/farmacologia , Carga Bacteriana/efeitos dos fármacos , Microbiologia de Alimentos/métodos , Carne/microbiologia , Ultrassom/normas , Animais , Galinhas/microbiologia , Temperatura Baixa , Eletrólise , Água/química
9.
Int J Food Microbiol ; 301: 51-60, 2019 Jul 16.
Artigo em Inglês | MEDLINE | ID: mdl-31100642

RESUMO

Wild boars (Sus scrofa) are the most widely distributed large mammals and recent increase in consumption of wild boar meat urges the need of microbiological quality criteria. The aim of the study was to characterize the initial bacterial contamination on freshly-killed wild boar meat using a culture-dependent approach with ISO-methods combined with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry identification and 16S rRNA amplicon sequencing. Moreover, the presence of foodborne pathogens was examined using Real-Time-PCR and confirmed by classical isolation. Analysing 22 unrelated wild boar meat samples showed a higher bacterial contamination level compared to pork, with Salmonella present in almost one third of the samples. A great variability of the microbial contamination between the samples was recorded, as well as complementary results between culturing and 16S rRNA amplicon sequencing as frequently isolated genera were not always detected, and vice versa. Furthermore, the foodborne pathogen Salmonella was never detected with 16S rRNA amplicon sequencing, demonstrating the necessity for a cautious approach in the implementation of new analysis techniques in food safety. The present work determines that attention should be paid to the trade of non-inspected meat directly to retail or consumers.


Assuntos
Carne/microbiologia , Microbiota/fisiologia , RNA Ribossômico 16S , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , Animais , Humanos , Microbiota/genética , RNA Ribossômico 16S/genética , Sus scrofa/microbiologia , Suínos
10.
Int J Food Microbiol ; 303: 32-41, 2019 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-31129476

RESUMO

Pathogens and spoilage microorganisms can develop multispecies biofilms on food contact surfaces; however, few studies have been focused on evaluated mixed biofilms of these microorganisms. Therefore this study investigated the biofilm development by pathogenic (Bacillus cereus, Escherichia coli, Listeria monocytogenes, and Salmonella enterica Enteritidis and Typhimurium serotypes) and spoilage (Bacillus cereus and Pseudomonas aeruginosa) microorganisms onto stainless-steel (SS) and polypropylene B (PP) coupons; under conditions that mimic the dairy, meat, and egg processing industry. Biofilms were developed in TSB with 10% chicken egg yolk (TSB + EY), TSB with 10% meat extract (TSB + ME) and whole milk (WM) onto SS and PP. Each tube was inoculated with 25 µL of each bacteria and then incubated at 9 or 25 °C, with enumeration at 1, 48, 120, 180 and 240 h. Biofilms were visualized by epifluorescence and scanning electron microscopy (SEM). Biofilm development occurred at different phases, depending on the incubation conditions. In the reversible adhesion, the cell density of each bacteria was between 1.43 and 6.08 Log10 CFU/cm2 (p < 0.05). Moreover, significant reductions in bacteria appeared at 9 °C between 1 and 48 h of incubation. Additionally, the constant multiplication of bacteria in the biofilm occurred at 25 °C between 48 and 180 h of incubation, with increments of 2.08 Log10 CFU/cm2 to S. Typhimurium. Population establishment was observed between 48 and 180 h and 180-240 h incubation, depending on the environmental conditions (25 and 9 °C, respectively). For example, in TSB + ME at 25 °C, S. Typhimurium, P aeruginosa, and L. monocytogenes showed no statistical differences in the amounts between 48 and 180 h incubation. The dispersion phase was identified for L. monocytogenes and B. cereus at 25 °C. Epifluorescence microscopy and SEM allowed visualizing the bacteria and extracellular polymeric substances at the different biofilm stages. In conclusion, pathogens and spoilage microorganisms developed monospecies with higher cellular densities than multiespecies biofilms. In multispecies biofilms, the time to reach each biofilm phase varied is depending on environmental factors. Cell count decrements of 1.12-2.44 Log10 CFU/cm2 occurred at 48 and 240 h and were most notable in the biofilms developed at 9 °C. Additionally, cell density reached by each microorganism was different, P. aeruginosa and Salmonella were the dominant microorganisms in the biofilms while B. cereus showed the lower densities until undetectable levels.


Assuntos
Biofilmes/crescimento & desenvolvimento , Ovos/microbiologia , Microbiologia de Alimentos , Indústria de Processamento de Alimentos , Carne/microbiologia , Animais , Aderência Bacteriana , Contagem de Colônia Microbiana , Cinética , Aves Domésticas , Aço Inoxidável
11.
Int J Syst Evol Microbiol ; 69(8): 2367-2371, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31145674

RESUMO

Two conspecific yeast strains, which based on DNA sequence comparisons represented an undescribed species in the order Trichosporonales were isolated during two independent studies in Hungary and France. One of them (NCAIM Y.02224) was recovered from minced pork in Hungary while the other one (UBOCC-A-218003) was isolated from the air of a dairy plant in France. The two strains shared identical nucleotide sequences in the D1/D2 domain of the nuclear large subunit (LSU) rRNA gene and in the internal transcribed spacer (ITS) region. Analysis of the concatenated DNA sequences for the ITS region and D1/D2 domain of the LSU rRNA gene indicated that the novel species belongs to the recently erected genus Cutaneotrichosporon. According to sequence comparisons and phylogenetic analysis, the novel species is most closely related to Cutaneotrichosporon curvatum (formerly Cryptococcus curvatus), which is often associated with humans and warm-blooded animals. The physiological characteristics of this novel species are also very similar to that of Cutaneotrichosporon curvatum. The only clear-cut difference is that, unlike C. curvatum, the novel species does not utilize imidazole as a nitrogen-source. The species name Cutaneotrichosporon suis sp. nov. is proposed to accommodate the above-noted two strains.


Assuntos
Basidiomycota/classificação , Microbiologia de Alimentos , Filogenia , Basidiomycota/isolamento & purificação , DNA Fúngico/genética , DNA Espaçador Ribossômico/genética , Indústria de Laticínios , França , Hungria , Carne/microbiologia , Técnicas de Tipagem Micológica , Análise de Sequência de DNA
12.
Int J Food Microbiol ; 299: 47-57, 2019 Jun 16.
Artigo em Inglês | MEDLINE | ID: mdl-30953995

RESUMO

The aim of this work was to study the influence of lemon and vinegar marinades on Salmonella inoculated on chicken fillets and stored under different storage temperatures for nine days in the presence of indigenous microbiota. In addition to this, model development for the determination of the inactivation boundaries and the prediction of pathogens response was attempted. The different acid concentrations in the marinades, the type of acid, the storage temperature as well as the duration of storage impacted the levels of pathogens and background flora. The higher tested concentrations (2% and 4% v/v for acetic and citric acid) were more effective against Salmonella and spoilage microorganisms than the lower ones (0.5 and 1% v/v for acetic and citric acid), while the intermediate concentrations (1, 1.5 and 2, 3% v/v for acetic and citric acid, respectively) presented differentiations of particular interest to the microbial responses to acidic stress. The aforementioned parameters also differentiated Salmonella serovars persistence and spoilage microorganisms dominance. Regarding model development, the probability of inactivation of Salmonella was satisfactorily predicted particularly in the case of acetic acid marination while in model validation, the majority of the vinegar marinated samples were correctly classified, whereas, in case of lemon marination, a higher number of misclassifications was observed, indicating a partial weakness of the model to predict the pathogens response at interface concentrations.


Assuntos
Microbiologia de Alimentos , Carne/microbiologia , Viabilidade Microbiana , Salmonella/fisiologia , Temperatura Ambiente , Ácidos/farmacologia , Animais , Galinhas , Contagem de Colônia Microbiana , Viabilidade Microbiana/efeitos dos fármacos , Salmonella/efeitos dos fármacos , Salmonella/crescimento & desenvolvimento , Fatores de Tempo
13.
Int J Food Microbiol ; 299: 64-70, 2019 Jun 16.
Artigo em Inglês | MEDLINE | ID: mdl-30978578

RESUMO

Essential oils extracted by hydro-distillation form date palm spathe (byproduct from date palm plants) were tested for their antibacterial activity against some food-borne pathogens. Listeria monocytogenes ATCC 7644, Staphylococcus aureus ATCC 29243, Salmonella enterica subsp. enterica serovar Enteritidis ATCC 13076 and E. coli ATCC 25922 were inhibited (11-13 mm inhibition zones) by spathe essential oils (SEOs) using the agar well assay (in vitro test). Staphylococcus aureus ATCC 29243 and E. coli ATCC 25922 were not detected in chicken meat treated with 1% (v/w) SEOs and subjected to abusive storage conditions (20 °C for 18 h). When treated with 0.5% SEO, counts of S. aureus and E. coli increased by only 0.2 and 0.7 log10 cfu/g, respectively, compared to the initial inoculated level in meat samples stored at 20 °C for 18 h. SEOs possessed DPPH radical scavenging activity with IC50 of 0.61 µg/ml. Forty one compounds were major constituents detected by GC-MS analysis of SEOs. 3,4-Dimethoxytoluene (38.12%) and 5,9-Undecadien-2-one (12.45%) were major compounds in extracted oils. Density and refractive index of SEOs were 0.987 and 1.5905, respectively. SOEs are added-value products from date palm, which could be employed in food industry and pharmaceuticals. The study is the first report on antibacterial activity of SEOs against L. monocytogenes ATCC 7644 and other standard food-borne pathogens in agar diffusion assay and food model (chicken meat). DPPH radical scavenging activity of SEOs has not previously been documented.


Assuntos
Bactérias/efeitos dos fármacos , Microbiologia de Alimentos/métodos , Óleos Voláteis/farmacologia , Phoeniceae/química , Animais , Antibacterianos/farmacologia , Galinhas , Escherichia coli/efeitos dos fármacos , Cromatografia Gasosa-Espectrometria de Massas , Concentração Inibidora 50 , Listeria monocytogenes/efeitos dos fármacos , Carne/microbiologia , Salmonella enteritidis/efeitos dos fármacos , Staphylococcus aureus/efeitos dos fármacos
14.
BMC Vet Res ; 15(1): 124, 2019 Apr 27.
Artigo em Inglês | MEDLINE | ID: mdl-31029108

RESUMO

BACKGROUND: This study aimed to survey the prevalence, antimicrobial resistance, and virulence-associated genes of Salmonella enterica recovered from broiler chickens and retail shops at El-Sharkia Province in Egypt. Salmonella virulence factors were determined using the polymerase chain reaction assays targeting the invA, csgD, hilC, bcfC, stn, avrA, mgtC, ompF, sopE1 and pefA genes. RESULTS: One hundred tweenty out of 420- samples from broiler chickens' cloacal swabs, farm environmental samples, and freshly dressed whole chicken carcasses were positive Salmonella species. The isolates were serotyped as S. Enteritidis as the most dominant serotypes. Interestingly, none of the isolates were resistant to imipenem. The multidrug resistance was determined in 76.7% of the isolates with multidrug antibiotic resistance index of 0.2-0.6. Eight virulence genes (invA, csgD, hilC, stn, bcfC, mgtC, avrA, and ompf) were characterized among 120 S. enterica isolates with variable frequencies, while sopE1and pefA genes that were completely absent in all isolates. Based on the combination of presence and absence of virulence genes, the most common genetic profile (P7, 30%) was invA and csgD genes. CONCLUSION: S. Enteritidis and S. Typhimurium were the most common identified serotypes in the examined sources. Circulation of such strains in broiler farms required introducing special biosecurity and biocontrol measures for control of Salmonella. Such measures might limit the adverse effects of antibiotics and ensure the safety of the environment and animal-derived food.


Assuntos
Antibacterianos/farmacologia , Farmacorresistência Bacteriana , Microbiologia de Alimentos , Carne/microbiologia , Salmonelose Animal/microbiologia , Salmonella enterica/efeitos dos fármacos , Animais , Galinhas , Egito/epidemiologia , Genótipo , Abrigo para Animais , Salmonelose Animal/epidemiologia , Salmonella enterica/genética , Salmonella enterica/isolamento & purificação , Salmonella enterica/patogenicidade , Virulência
15.
Int J Food Microbiol ; 300: 14-21, 2019 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-30991234

RESUMO

It is well established, that certain bacteria within the Brochothrix, Carnobacterium, Lactobacillus, Lactococcus, and Leuconostoc genera have an important role in the spoilage of chill stored poultry meat packaged in modified atmosphere. However, little is known about the role of microorganisms that are difficult to culture and the microbiota during poultry spoilage. We combined traditional cultivation and culture-independent 16S rRNA amplicon sequencing to investigate the microbiota encompassing putative bacteria of whole broiler meat, packaged in modified atmosphere, during and exceeding shelf-life. Samples were taken from 6 flocks during independent slaughter days. Additional samples were analysed from the production line. There was a significant difference in the microbial community structure of 80%O2/20%CO2 retail packaged broiler meat during different times of shelf-life, mainly due to an increase of species within the Brochothrix, Carnobacterium, Vagococcus, and Janthinobacterium genera. These genera were already detected four to eight days after slaughter. However, no significant difference between flocks with respect to the microbiota encompassing putative spoilage bacteria was observed when examined in retail packaged broilers, slaughtered at the same abattoir on different days. Our study also showed that lactic acid bacteria within the Vagococcus genus can constitute a dominating part of the later shelf-life microbiota in fresh whole broiler meat packaged in 80%O2/20%CO2 modified atmosphere. A single operational taxonomic unit (OTU) assigned as Janthinobacterium lividum, an occasional spoiler of meat products, was identified as a major part of the microbiota in late shelf life broiler meat and swab samples in the cooling facility at the slaughter house production line. The combination of traditional cultivation and culture-independent methods provided a great insight into the microbiota of broiler meat during shelf-life and identified a potential point of contamination in the production line for cold tolerant Janthinobacterium.


Assuntos
Fenômenos Fisiológicos Bacterianos , Galinhas/microbiologia , Microbiologia de Alimentos , Carne/microbiologia , Microbiota/fisiologia , Matadouros , Animais , Bactérias/genética , Bactérias/crescimento & desenvolvimento , Carnobacterium/genética , Carnobacterium/fisiologia , Galinhas/genética , Embalagem de Alimentos , Microbiota/genética , RNA Ribossômico 16S/genética
16.
Acta Sci Pol Technol Aliment ; 18(1): 43-52, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30927751

RESUMO

BACKGROUND: Worldwide, poultry is considered the main source of food-related human campylobacteriosis, which is generally associated with the consumption of raw or undercooked chicken meat. Furthermore, Cam- pylobacter develops biofilms that are resistant to environmental stress, antibiotics, and disinfectants and are becoming a major issue for the food industry, especially the poultry industry. This study investigated the antimicrobial and anti-biofilm properties of polyphenols found in spray-dried olive mill wastewater (OMWW--SD) against Campylobacter strains isolated from chicken meat. METHODS: OMWW-SD was produced by dehydration of olive mill wastewater polyphenolic extract. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) for OMWW-SD were determined by microdilution method whereas the inhibitory effect of the OMWW-SD on biofilm formation and biofilm disaggregation was tested through crystal violet assay on polystyrene plates. RESULTS: The phenolic profile of OMWW-SD mainly consisted of secoiridoid and hydroxycinnamic acid derivatives. Oleuropein-aglycone di-aldehyde (a secoiridoid derivative) was the major constituent, representing 72.5% of the total identified phenolic compounds. OMWW-SD showed a MIC ranging from 0.15 mg/mL to 0.3 mg/mL and a MBC of 0.3 mg/mL for all Campylobacter strains tested. The olive by-product extract tested was able, in vitro, to inhibit biofilm formation and to promote biofilm dispersion even at sub-MIC concentra- tions, with values ranging from 6% to 92% and from 4% to 83% at varying extract dilutions, respectively. CONCLUSIONS: OMWW-SD could be developed as a new anti-biofilm agent with potential to control Campylo- bacter in the food chain, especially in the poultry industry, thereby enhancing food safety.


Assuntos
Antibacterianos/farmacologia , Biofilmes/efeitos dos fármacos , Campylobacter/efeitos dos fármacos , Microbiologia de Alimentos , Carne/microbiologia , Azeite de Oliva/química , Animais , Antibacterianos/química , Galinhas , Indústria Alimentícia , Resíduos Industriais/análise , Águas Residuárias/química
17.
Food Microbiol ; 82: 515-522, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31027813

RESUMO

The formation of biofilms in the food industry is a major issue, as they are a frequent source of contamination of products, which can result in significant economic losses for processors through spoilage of foods or pose serious health concerns for consumers when foodborne pathogens are present. In this study, experiments were carried out using CDC Biofilm Reactors to produce biofilms on two test surfaces (polystyrene and stainless steel coupons) under a regimen for simulated meat processing conditions (SMPC). This entailed a 12 day regimen of daily cycles of filling the reactors with a meat slurry and letting stand for 16 h, followed by draining and refilling with water for an 8 h period in order to mimic a possible scenario of fluctuating periods of nutrient availability and starvation in a meat processing facility. Strains of Pseudomonas fluorescens, Lactobacillus plantarum and Leuconostoc pseudomesenteroides were used for mono and mixed cultures biofilms as they are relevant spoilage bacteria in the meat processing industry. In monoculture, the viable cell densities (CFU/cm2) of the two lactic acid bacteria species tested were higher for biofilms grown on polystyrene as compared to those obtained on stainless steel, whereas viable cell numbers in P. fluorescens monoculture were surface-independent. Synergistic interactions were demonstrated during growth of multi-species biofilms. Results from experiments where one of the 3 strains was inoculated 24 h before introduction of the other two strains showed increased levels of L. plantarum within biofilms grown on both test surfaces. The model developed here serves as a baseline to study the interactions between potential spoilage bacteria during biofilm development.


Assuntos
Bactérias/crescimento & desenvolvimento , Biofilmes , Microbiologia de Alimentos , Carne/microbiologia , Interações Microbianas , Bactérias/classificação , Aderência Bacteriana , Biofilmes/crescimento & desenvolvimento , Contagem de Colônia Microbiana , Manipulação de Alimentos , Microbiota , Poliestirenos , Aço Inoxidável
18.
Food Microbiol ; 82: 53-61, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31027815

RESUMO

Examination of the bacterial contamination on food products is still largely performed by standardized culture methods, though culture-independent methods are suggested as a more reliable approach. Knowledge of the diversity of bacteria isolated from food as well as the impact of the plate incubation conditions applied are still understudied. The impact of incubation at 7 °C and 30 °C on total aerobic bacterial count and diversity, and the performance of ISO methods generally applied in microbiological quality examination were assessed by culture combined MALDI-TOF MS identification and 16S rRNA amplicon sequencing. Examining breast skin of 16 chicken carcasses, no significant impact of the incubation temperature on the total aerobic bacteria level and diversity was detected, limiting the usefulness of additional psychrophilic examination. Bacteria phenotypically similar to Pseudomonas, were identified on selective CFC plates, and on MRS agar plates for lactic acid bacteria, Escherichia coli and Staphylococcus were commonly present. Application of 16S rRNA amplicon sequencing revealed a higher bacterial diversity, but the impact of the DNA extraction kit applied, and the detection of non-viable bacteria should be taken into account to interpret the final outcome.


Assuntos
Bactérias/isolamento & purificação , Microbiologia de Alimentos/métodos , Carne/microbiologia , Aves Domésticas/microbiologia , Análise de Sequência de DNA , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , Animais , Bactérias/classificação , Técnicas de Tipagem Bacteriana , DNA Bacteriano/genética , Escherichia coli/genética , Escherichia coli/isolamento & purificação , Variação Genética , Filogenia , Pseudomonas/genética , Pseudomonas/isolamento & purificação , RNA Ribossômico 16S/genética , Staphylococcus/genética , Staphylococcus/isolamento & purificação
19.
Food Microbiol ; 82: 249-253, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31027780

RESUMO

Recent outbreaks of Campylobacter mediated disease attributed to undercooked chicken livers have highlighted a continuing need for methods to reduce Campylobacter numbers in these types of food products. In this study, gamma irradiation is evaluated for its effectiveness in reducing Campylobacter jejuni numbers in experimentally contaminated chicken livers. A wide range of radiation doses were evaluated in conjunction with cold storage parameters, before and after irradiation. Storage of chicken livers at -20 °C prior to radiation treatment, as expected, increased C. jejuni radiation resistance. Livers previously stored at -20 °C exhibited D10 values of 0.748 kiloGray (kGy) compared to livers without previous storage that had a significantly lower D10 value of 0.361 kGy. Cold storage conditions post-irradiation at both 4 °C and -20 °C further reduced the C. jejuni numbers over those reduced by the initial irradiation. The largest reduction (3.8 logs) of C. jejuni numbers in livers produced by combining irradiation and cold storage was achieved using 0.8 kGy of radiation followed by 1 week storage at -20 °C. This reduction of 3.8 logs was not determined to be significantly different from the 3.5 log reduction achieved with the same radiation dose (0.8 kGy) after only 48 h of subsequent storage at -20 °C.


Assuntos
Campylobacter jejuni/efeitos da radiação , Microbiologia de Alimentos , Armazenamento de Alimentos/métodos , Fígado/microbiologia , Carne/microbiologia , Animais , Campylobacter jejuni/crescimento & desenvolvimento , Galinhas , Temperatura Baixa , Contagem de Colônia Microbiana , Irradiação de Alimentos , Raios gama , Doses de Radiação , Fatores de Tempo
20.
Future Microbiol ; 14: 609-622, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30995873

RESUMO

Aim: This research pioneers the process of obtaining information concerning the distribution and existence of seven ESBL genes linked to Pseudomonas, three virulence and five quorum sensing separated from 100 camel meat samples using PCR. Materials & methods: The Vitek system was used to identify Pseudomonas species. Phenotypic antibiotic resistance of 16 antibiotics was tested by disc diffusion. Quantification of pyocyanin, elastase, alkaline protease, biofilm and Vero cell cytotoxicity was also implemented. Results: The total number of Pseudomonas species isolated from camel meat was 10/100 identified as Pseudomonas aeruginosa 8/10, Pseudomonas fluorescens 2/10. The isolates were multidrug resistant and were resistant to four to eight antibiotics representing four to six classes. The 15 genes exhibited a huge diversity in their association. Conclusion: The results indicated that camel meat is an unpropitious hotbed for Pseudomonas species of clinical significance.


Assuntos
Biofilmes/crescimento & desenvolvimento , Farmacorresistência Bacteriana Múltipla/genética , Carne/microbiologia , Infecções por Pseudomonas/microbiologia , Infecções por Pseudomonas/veterinária , Pseudomonas/efeitos dos fármacos , Pseudomonas/genética , Percepção de Quorum/genética , Fatores de Virulência/genética , Animais , Antibacterianos/farmacologia , Proteínas de Bactérias , Camelus , Cercopithecus aethiops , Testes de Sensibilidade a Antimicrobianos por Disco-Difusão , Farmacorresistência Bacteriana Múltipla/efeitos dos fármacos , Egito/epidemiologia , Endopeptidases , Microbiologia de Alimentos , Genes Bacterianos/genética , Elastase Pancreática , Reação em Cadeia da Polimerase/métodos , Pseudomonas/classificação , Pseudomonas/isolamento & purificação , Infecções por Pseudomonas/epidemiologia , Pseudomonas aeruginosa/efeitos dos fármacos , Pseudomonas aeruginosa/isolamento & purificação , Pseudomonas fluorescens/efeitos dos fármacos , Pseudomonas fluorescens/isolamento & purificação , Piocianina , Células Vero , Virulência/genética , beta-Lactamases/genética
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