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1.
Braz J Microbiol ; 2024 Aug 30.
Artículo en Inglés | MEDLINE | ID: mdl-39212841

RESUMEN

This study aimed to investigate the influence of adding an alkalizing agent to the scalding water of a slaughterhouse in Brazil to inactivate hygiene indicator bacteria in pig carcasses. Scalding is critical during carcass processing because slaughterhouses' scalding water is constantly renewed; therefore, it is usually contaminated with organic matter, such as faeces and dirt from the previous carcasses. The treatments evaluated consisted of counting Enterobacteriaceae and mesophilic bacteria in pork jowls at 62 °C, 65 °C, 68 C, and 72 °C after 0.0, 1.5, 3.0, 4.5, 6.0, and 7.5 min of simulated scalding at the pHs of 7.0 (control) and 11.0 (after addition of alkalizing agent). Decimal reduction times of hygiene indicator bacteria for all treatments were estimated with different nonlinear bacterial inactivation models. As a result, adding the alkalizing agent did not significantly inactivate most of the bacteria in the studied samples. However, it contributed to the inactivation of some bacteria, mostly belonging to the mesophilic group, at some specific temperatures. The results obtained in the current study can provide useful insights into dealing with pig carcass contamination in a real-world scenario and applying the obtained information in the industrial environment.

2.
Food Microbiol ; 119: 104452, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38225053

RESUMEN

The current study was conducted to statistically compare the SYBR® Green quantitative polymerase chain reaction (qPCR) assay and the conventional plate counting (PC) method to construct growth curves of a cocktail of Weissella viridescens in pure culture under different isothermal storage conditions (4, 8, 14, and 30 °C) and in mixed culture with Leuconostoc mesenteroides at 8 °C. The efficiency and specificity of the qPCR standard curves were confirmed, and both methods were adequate to quantify the growth kinetics of W. viridescens at all isothermal temperatures, demonstrating a good correlation and agreement. The efficiencies of the standard curves varied between 98% and 102%. The SYBR® Green qPCR assay was also able to differentiate the growth curves of W. viridescens and L. mesenteroides in the mixed culture at 8 °C. Additionally, the SYBR® Green qPCR method was considered a faster and more sensitive alternative to construct growth curves under different isothermal conditions and differentiate morphologically similar lactic acid bacteria. Overall, the results suggest that the SYBR® Green qPCR method is a reliable and efficient tool to study microbial growth kinetics in pure and mixed cultures.


Asunto(s)
Lactobacillales , Leuconostoc mesenteroides , Weissella , Lactobacillus , Weissella/genética , Leuconostoc/genética
3.
Braz J Microbiol ; 54(1): 323-334, 2023 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-36740644

RESUMEN

The growth of the lactic acid bacteria (LAB), Streptococcus thermophilus and Lactobacillus bulgaricus, widely used for yogurt production, results in acid production and the reduction of the milk [Formula: see text]. Industrial processes can show temperature ([Formula: see text]) changes due to the large scale of the equipment. As [Formula: see text] and [Formula: see text] affect the LAB growth, this study aimed to model the dependence of S. thermophilus and L. bulgaricus as a function of temperature and pH and to estimate and internally validate their growth parameters and confidence intervals with different modeling approaches. Twenty-four datasets regarding the growth kinetics of S. thermophilus and L. bulgaricus were used for estimating the kinetic parameters for each pure culture. The classical Baranyi and Roberts (sigmoidal) primary and Rosso and coworkers (cardinal parameter) secondary models successfully described the experimental data. The one-step modeling approach showed better statistical results than the two-step approach. The values of eight growth parameters ([Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], and [Formula: see text]) for each culture estimated from the fitting with the one-step approach and the Monte-Carlo-based approach were similar. Low averaged root-mean-squared errors ([Formula: see text]) (0.125 and 0.090 log CFU/mL) and percent discrepancy factor [Formula: see text] ([Formula: see text] and [Formula: see text]) values for S. thermophilus and L. bulgaricus were obtained in the internal model validation, reinforcing the predictive ability of the model.


Asunto(s)
Lactobacillus delbrueckii , Streptococcus thermophilus , Lactobacillus , Temperatura , Concentración de Iones de Hidrógeno , Fermentación
4.
J Microbiol Methods ; 205: 106674, 2023 02.
Artículo en Inglés | MEDLINE | ID: mdl-36641085

RESUMEN

Isothermal microcalorimetry can provide a general analytical tool for the characterization of bacterial growth. Methodologies and equipment have been studied to expand the application and disseminate the use of the technique. The MCDSC is a microcalorimeter capable of measuring in the range of 0.2 µW that can operate at a temperature range of -20 to 140 °C or under isothermal conditions. Here, we present the first investigation of MCDSC for E. coli growth with the Baranyi and Roberts modeling application. This study presented the calorimetric E. coli fingerprint at MCDSC and compares it with the plate count technique, giving the data more biological meaning. The calorimeter was able to accurately detect growth metabolism and discriminate E. coli at different inoculum densities. Additionally, the MCDSC can offer a new point of view for evaluating microbial growth, such as the significant reduction in error due to dispersed data by the viable counting method.


Asunto(s)
Escherichia coli , Calorimetría/métodos , Temperatura , Recuento de Colonia Microbiana
5.
Arch Microbiol ; 204(10): 618, 2022 Sep 13.
Artículo en Inglés | MEDLINE | ID: mdl-36098860

RESUMEN

This study aimed to evaluate and model the antimicrobial action of different concentrations of Croton blanchetianus essential oil (CBEO) on the behavior of six bacterial species in vitro. CBEO extraction was performed by hydrodistillation and characterized by CG-MS. CBEO solutions in culture media were tested at 0.90, 1.80, 2.71, and 4.51 mg of CBEO/mL, against foodborne bacteria: pathogenic bacteria (Staphylococcus aureus, Listeria monocytogenes and Salmonella Enteritidis at 35 °C), a non-pathogenic Escherichia coli (at 35 °C), and spoilage bacteria (Weissella viridescens and Leuconostoc mesenteroides at 30 °C). The CBEO major compounds were eucalyptol, α-pinene, sativene, E-caryophyllene, bicyclogermacrene, and spatulenol. Baranyi and Roberts (growth) and Weibull (inactivation) primary models, along with power and hyperbolic secondary models, were able to describe the data. CBEO inactivated L. monocytogenes, S. aureus, L. mesenteroides and W. viridescens at all applied concentrations. CBEO did not inactivate S. Enteritidis and E. coli, but their growth rates were reduced.


Asunto(s)
Croton , Listeria monocytogenes , Aceites Volátiles , Antibacterianos/farmacología , Aceite de Crotón/farmacología , Escherichia coli , Aceites Volátiles/farmacología , Staphylococcus aureus
6.
J Appl Microbiol ; 132(5): 3973-3986, 2022 May.
Artículo en Inglés | MEDLINE | ID: mdl-35262283

RESUMEN

AIMS: This study evaluated the behaviour of the Salmonella enterica serotypes in osmotically stressful BHI broth (0.940 ≤ aw  ≤ 0.960), assessing inoculum from two stages of the bacterial life cycle (exponential and stationary) and two temperatures (25°C and 35°C). METHODS AND RESULTS: Four S. enterica serotypes (Typhimurium, Enteritidis, Heidelberg and Minnesota) were grown in stressful BHI at 25°C. A mathematical model was proposed for describing the total microbial count as the sum of two subpopulations, inactivating and surviving-then-growing. When submitted to aw of 0.950 and 0.960, all strains showed a decreased count, followed by a period of unchanged count and then exponential growth (Phoenix Phenomenon). Strains inoculated at aw  = 0.940 and 0.945 showed inactivation kinetics only. Cells cultivated at 25°C and inoculated from the exponential phase were the most reactive to the osmotic stress, showing a higher initial population reduction and shorter adaptation period. The proposed model described the inactivation data and the Phoenix Phenomenon accurately. CONCLUSIONS: The results quantified the complex response of S. enterica to the osmotic environment in detail, depending on the inoculum characteristic and serotype evaluated. SIGNIFICANCE AND IMPACT OF STUDY: Quantifying these differences is truly relevant to food safety and improves risk analysis.


Asunto(s)
Salmonella enterica , Recuento de Colonia Microbiana , Microbiología de Alimentos , Presión Osmótica , Serogrupo , Agua/análisis
7.
J Food Sci Technol ; 58(12): 4524-4529, 2021 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-34629516

RESUMEN

This work aimed to evaluate the lipid oxidation, color, and sensory acceptance of sausages formulated with potassium bixinate (BP) as a substitute for carmine (Car) and sodium nitrite (SNi). Six different treatments (CT-control; CA-40 ppm Car; NIT-150 ppm SNi; C/N-40 ppm Car, and 150 ppm SNi; C/N/B-20 ppm Car, 75 ppm SNi, and 250 ppm BP; and BIX-500 ppm BP) were evaluated along 15 days. BP provided significantly lower levels of lipid oxidation to the samples (C/N/B and BIX) when compared to CT and significantly equal to CA, NIT, and C/N after 15 days (both p < 0.05). BP significantly increased the red (a*) and yellow (b*) intensity of sausages (p < 0.05), providing the highest values in both raw and roasted samples. Sausages formulated with BP did not differ in preference in visual analysis (p > 0.05), and both roasted were preferred over CT (p < 0.05). Although sausages formulated with carmine had better visual acceptance, BIX and C/N did not differ significantly (p > 0.05) after five days. BP was identified in taste analysis; however, it was preferred in the ordination analysis (both p < 0.01). Therefore, the replacement of SNi and Car by BP showed to be a viable alternative.

8.
SN Compr Clin Med ; 3(9): 1863-1869, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34179692

RESUMEN

COVID-19 represented an important challenge to the Italian healthcare system (IHCS). Our main aim was to obtain evidence to support the use of modified national early warning score (m-NEWS) as an interdisciplinary, common, and universal scoring scale to quickly recognize patients with a risk of clinical deterioration before admission and during hospitalization. As a secondary goal, we tried to find a score threshold that can trigger patients' immediate medical review as a part of an optimal triaging protocol for an emergency setting where healthcare resources are overloaded. We performed a retrospective observational study. We included in our study all patients treated for COVID-19 infection in surgical departments between 01 March 2020 and 16 April 2020. Patients with negative test results for SARS-COV-2 were excluded. m-NEWS was obtained twice a day. Patients' m-NEWS were analyzed in order to verify the correlation between m-NEWS (at admission and m-NEWS variation 24 h after admission) and outcome (positive outcome-survival, negative outcome-death, or intensive care unit (ICU) transfer). We included a population-based sample of 225 SARS-COV-2-infected patients. Overall, the average age at hospitalization was 71 (ranging from 40 to 95). 144 (64%) patients were males and 81 (36%) females. m-NEWS values lower or equal to 7 were associated with the majority of the "recovered" population (100/132 75.75%) and at the same time with the minority of the "non-recovered" population (25/93 26.88%). For our sample, age is statistically correlated to the outcome but a triage protocol based solely on this variable is less effective than m-NEWS, which showed to be a reliable and easy-to-use score for first patient evaluation. Our observations pave the way towards further studies aiming at optimizing territorial and community healthcare management protocols.

9.
Int J Food Microbiol ; 344: 109110, 2021 Apr 16.
Artículo en Inglés | MEDLINE | ID: mdl-33657496

RESUMEN

Salmonella genus has foodborne pathogen species commonly involved in many outbreaks related to the consumption of chicken meat. Many studies have aimed to model bacterial inactivation as a function of the temperature. Due to the large heterogeneity of the results, a unified description of Salmonella spp. inactivation behavior is hard to establish. In the current study, by evaluating the root mean square errors, mean absolute deviation, and Akaike and Bayesian information criteria, the double Weibull model was considered the most accurate primary model to fit 61 datasets of Salmonella inactivation in chicken meat. Results can be interpreted as if the bacterial population is divided into two subpopulations consisting of one more resistant (2.3% of the total population) and one more sensitive to thermal stress (97.7% of the total population). The thermal sensitivity of the bacteria depends on the fat content of the chicken meat. From an adapted version of the Bigelow secondary model including both temperature and fat content, 90% of the Salmonella population can be inactivated after heating at 60 °C of chicken breast, thigh muscles, wings, and skin during approximately 2.5, 5.0, 9.5, and 57.4 min, respectively. The resulting model was applied to four different non-isothermal temperature profiles regarding Salmonella growth in chicken meat. Model performance for the non-isothermal profiles was evaluated by the acceptable prediction zone concept. Results showed that >80% of the predictions fell in the acceptable prediction zone when the temperature changes smoothly at temperature rates lower than 20 °C/min. Results obtained can be used in risk assessment models regarding contamination with Salmonella spp. in chicken parts with different fat contents.


Asunto(s)
Pollos/microbiología , Calor , Carne/microbiología , Intoxicación Alimentaria por Salmonella/prevención & control , Salmonella/crecimiento & desarrollo , Animales , Teorema de Bayes , Recuento de Colonia Microbiana , Microbiología de Alimentos , Salmonella/clasificación
10.
Int J Food Microbiol ; 333: 108773, 2020 Nov 16.
Artículo en Inglés | MEDLINE | ID: mdl-32739634

RESUMEN

The present work aimed to evaluate and to model the influence of UV-C light treatments with different irradiances (6.5, 13, 21, and 36 W/m2) on Aspergillus fischeri and Paecilomyces niveus ascospores inactivation in clarified apple juice. Approximately 5.0 and 6.0 log CFU/mL spores of P. niveus and A. fischeri, respectively, were suspended in 30 mL of clarified apple juice (pH 3.8, 12 ± 0.1°Brix) and exposed to UV-C light at different irradiances (as above) and exposure times (0 to 30 min). The first-order biphasic model was able to describe the experimental data with good statistical indices (RMSE = 0.296 and 0.308, R2 = 0.96 and 0.98, for P. niveus and A. fischeri respectively). At the highest irradiance level tested (36 W/m2), the UV-C light allowed the reduction of 5.7 and 4.2 log-cycles of A. fischeri and P. niveus ascospores, respectively, in approximately 10 min. P. niveus was the most UV-C resistant mould. The results showed that, to a defined UV-C fluence, a change in the level of either time or UV-C irradiance did not affect the effectiveness of UV-C light for A. fischeri and P. niveus inactivation. Thus, the modeling of the inactivation as a function of the UV-C fluence allowed the estimation of the primary model parameters with all experimental data and, consequently, no secondary models were needed. The model parameters were validated with experiments of variable UV-C fluences. Accordingly, experimental results allowed to conclude that UV-C treatment at the irradiances tested is a promising application for preventing A. fischeri and P. niveus spoilage of juices.


Asunto(s)
Aspergillus/efectos de la radiación , Jugos de Frutas y Vegetales/microbiología , Paecilomyces/efectos de la radiación , Esporas Fúngicas/efectos de la radiación , Rayos Ultravioleta , Byssochlamys/clasificación , Microbiología de Alimentos , Malus/microbiología , Neosartorya/clasificación
11.
Int J Food Microbiol ; 318: 108466, 2020 Apr 02.
Artículo en Inglés | MEDLINE | ID: mdl-31865245

RESUMEN

The TaqMan-based quantitative Polymerase Chain Reaction (qPCR) method and the Plate Count (PC) method are both used in combination with primary and secondary mathematical modeling, to describe the growth curves of Leuconostoc mesenteroides and Weissella viridescens in vacuum-packaged meat products during storage under different isothermal conditions. Vacuum-Packaged Morcilla (VPM), a typical cooked blood sausage, is used as a representative meat product, with the aim of improving shelf-life prediction methods for those sorts of meat products. The standard curves constructed by qPCR showed good linearity between the cycle threshold (CT) and log10 CFU/g, demonstrating the high precision and the reproducible results of the qPCR method. The curves were used for the quantification of L. mesenteroides and W. viridescens in artificially inoculated VPM samples under isothermal storage (5, 8, 13 and 18 °C). Primally, both the qPCR and the PC methods were compared, and a linear regression analysis demonstrated a statistically significant linear correlation between the methods. Secondly, the Baranyi and Roberts model was fitted to the growth curve data to estimate the kinetic parameters of L. mesenteroides and W. viridescens under isothermal conditions, and secondary models were used to establish the dependence of the maximum specific growth rate on the temperature. The results proved that primary and secondary models were adequate for describing the growth curves of both methods in relation to both bacteria. In conclusion, the results of all the experiments proved that the qPCR method in combination with the PC method can be used to construct microbial growth kinetics and that primary and secondary mathematical modeling can be successfully applied to describe the growth of L. mesenteroides and W. viridescens in vacuum-packaged morcilla and, by extension, other cooked meat products with similar characteristics.


Asunto(s)
Microbiología de Alimentos/métodos , Embalaje de Alimentos/métodos , Lactobacillales/crecimiento & desarrollo , Productos de la Carne/microbiología , Modelos Teóricos , Animales , Recuento de Colonia Microbiana , Reacción en Cadena en Tiempo Real de la Polimerasa , Temperatura , Vacio
12.
Meat Sci ; 139: 113-119, 2018 May.
Artículo en Inglés | MEDLINE | ID: mdl-29413670

RESUMEN

The present study modeled the effect of oregano essential oil, as an antimicrobial agent, on the shelf-life of vacuum-packed cooked sliced ham, based on the growth of lactic acid bacteria natural microbiota under isothermal conditions. The bacterial growth in ham without oregano essential oil (control) and with 0.4% oregano essential oil (v/w) was evaluated at five different temperatures (6, 12, 15, 20 and 25°C). Baranyi and Roberts, and modified Gompertz primary models were fitted to microbial growth curves. Square Root and Exponential secondary models were fitted to µmax parameter data. The addition of oregano essential oil increased lag phase, decreased growth rates and extended shelf-life of ham for all temperatures (at 6°C extended for, at least, 30days when compared to control). Statistical indexes showed that Baranyi and Roberts, and Exponential were the primary and secondary models, respectively, that better fit to the data. Thus, oregano essential oil showed a good antimicrobial effect and extended the ham shelf-life.


Asunto(s)
Antiinfecciosos/farmacología , Productos de la Carne/microbiología , Aceites Volátiles/farmacología , Origanum/química , Animales , Microbiología de Alimentos , Conservantes de Alimentos/farmacología , Almacenamiento de Alimentos , Lactobacillales/efectos de los fármacos , Lactobacillales/crecimiento & desarrollo , Productos de la Carne/análisis , Porcinos , Temperatura
13.
Braz. arch. biol. technol ; 61: e18160159, 2018. tab, graf
Artículo en Inglés | LILACS | ID: biblio-951494

RESUMEN

ABSTRACT Mathematical models are widely used to predict the shelf life of foods. Lactic acid bacteria (LAB), particularly Lactobacillus plantarum, Weissella viridescens and Lactobacillus sakei, are the main spoilage bacteria of refrigerated, vacuum-packed meat products, stored in modified atmosphere, and their growth determines the shelf life length of these products. The objective of this study was to model the growth of L. plantarum, W. viridescens and L. sakei under different isothermal cultivation conditions and establish secondary models to describe the effect of temperature on the growth parameters of these bacteria. The LAB growth was evaluated in culture medium at temperatures of 4, 8, 12, 16, 20 and 30 ºC. The fit of Baranyi and Roberts (BAR) and Gompertz (GO) primary models to the growth curves of LAB was compared by statistical indices, in which the BAR model showed slightly better fits to the experimental data. The BAR growth parameters were used to establish the secondary models, µmax and Nmax were established for the three LAB. The power model described the influence of temperature on the parameter λ for L. plantarum, and other bacteria showed no lag phase. The growth of LAB was strongly influenced by storage temperature and the obtained models allow predicting the growth of these bacteria within the temperature range from 4 to 30 ºC.

14.
Rev. bras. cir. plást ; 32(4): 480-485, out.-dez. 2017. ilus
Artículo en Inglés, Portugués | LILACS | ID: biblio-878742

RESUMEN

Introdução: A rinoplastia de aumento em muitos casos torna-se mais difícil que a rinoplastia de redução. Enxertos dorsais sólidos realizados com cartilagem costal têm sido muito utilizados para aumento dorsal, porém estão associados com altos índices de revisão, por isso, muitos autores passaram a utilizar cartilagem em cubos envoltos por fáscia. A fáscia da mastoide, conectada ao pericôndrio da cartilagem conchal auricular, pode formar um enxerto composto para o aumento do dorso nasal, sendo também uma opção de tratamento. O objetivo é demonstrar a possibilidade do uso de cartilagem da concha auricular fragmentada fixa ao seu pericôndrio, e envoltos na fáscia da mastoide, formando um enxerto composto para aumento do dorso nasal. Métodos: Tratase de um estudo retrospectivo de 9 pacientes operados entre 2012 e 2016 no Hospital de Base da Faculdade de Medicina de São José do Rio Preto, em que foi realizado aumento do dorso nasal com cartilagem conchal fragmentada fixa ao seu pericôndrio e envolto à fáscia da mastoide. Resultados: Os pacientes foram acompanhados de 6 a 48 meses. Foram questionados quanto à satisfação do procedimento nasal e sensibilidade auricular, com avaliação positiva dos pacientes e cirurgiões. Conclusão: A cartilagem conchal parece ser uma alternativa de grande valia para procedimentos de aumento de dorso nasal. Esta cartilagem envolta com fáscia da mastoide parece ser uma alternativa vantajosa em comparação ao uso de outras fáscias, com baixa morbidade e taxa de complicações, podendo ser uma grande opção para tratamento do nariz em sela.


Introduction: In many cases, augmentation rhinoplasty is more difficult than reduction rhinoplasty. Solid dorsal grafts performed with costal cartilage have been widely used for dorsal augmentation; however, they are associated with high rates of revision. Thus, many authors began to use cartilage cut into cubes wrapped in fascia. The mastoid fascia, connected to the perichondrium of the auricular conchal cartilage can form a composite graft to augment the nasal dorsum, which is also a treatment option. The objective is to demonstrate the possibility of using fragmented auricular conchal cartilage fixed to its perichondrium and wrapped in mastoid fascia to form a composite graft for augmentation of the nasal dorsum. Methods: This is a retrospective study of 9 patients who underwent operation between 2012 and 2016 at the Base Hospital of the Faculty of Medicine of São José do Rio Preto, in which the nasal dorsum was augmented with fragmented conchal cartilage fixed to its perichondrium and wrapped in the mastoid fascia. Results: The patients were followed up for up 6 to 48 months. They were questioned about their satisfaction with the nasal procedure and hearing sensitivity, and provided a positive evaluation of the surgeons. Conclusion: The conchal cartilage seems a highly valuable alternative graft for nasal dorsum augmentation procedures. The technique of using cartilage wrapped in mastoid fascia seems to be an advantageous alternative when compared with those using cartilage wrapped in other fasciae: it has low morbidity and complications rates and can be a great option for saddle nose treatment.


Asunto(s)
Humanos , Masculino , Femenino , Historia del Siglo XXI , Rinoplastia , Cirugía Plástica , Nariz , Deformidades Adquiridas Nasales , Cartílagos Nasales , Hueso Nasal , Rinoplastia/métodos , Cirugía Plástica/métodos , Nariz/anomalías , Nariz/cirugía , Deformidades Adquiridas Nasales/cirugía , Deformidades Adquiridas Nasales/complicaciones , Cartílagos Nasales/anomalías , Cartílagos Nasales/cirugía , Hueso Nasal/anomalías , Hueso Nasal/cirugía
15.
Int J Food Microbiol ; 240: 97-101, 2017 Jan 02.
Artículo en Inglés | MEDLINE | ID: mdl-27207810

RESUMEN

Lactic acid bacteria (LAB) are responsible for spoiling vacuum-packed meat products, such as ham. Since the temperature is the main factor affecting the microbial dynamic, the use of mathematical models describing the microbial behavior into a non-isothermal environment can be very useful for predicting food shelf life. In this study, the growth of Lactobacillus viridescens was measured in vacuum-packed sliced ham under non-isothermal conditions, and the predictive ability of primary (Baranyi and Roberts, 1994) and secondary (Square Root) models were assessed using parameters estimated in MRS culture medium under isothermal conditions (between 4 and 30°C). Fresh ham piece was sterilized, sliced, inoculated, vacuum-packed, and stored in a temperature-controlled incubator at five different non-isothermal conditions (between 4 and 25°C) and one isothermal condition (8°C). The mathematical models obtained in MRS medium were assessed by comparing predicted values with L. viridescens growth data in vacuum-packed ham. Its predictive ability was assessed through statistical indexes, with good results (bias factor between 0.95 and 1.03; accuracy factor between 1.04 and 1.07, and RMSE between 0.76 and 1.33), especially in increasing temperature, which predictions were safe. The model parameters obtained from isothermal growth data in MRS medium enabled to estimate the shelf life of a commercial ham under non-isothermal conditions in the temperature range analyzed.


Asunto(s)
Microbiología de Alimentos/métodos , Embalaje de Alimentos/métodos , Conservación de Alimentos/métodos , Almacenamiento de Alimentos , Lactobacillus/crecimiento & desarrollo , Productos de la Carne/microbiología , Modelos Biológicos , Animales , Recuento de Colonia Microbiana , Porcinos , Temperatura
16.
Int J Food Microbiol ; 240: 57-62, 2017 Jan 02.
Artículo en Inglés | MEDLINE | ID: mdl-27427489

RESUMEN

In predictive microbiology, the model parameters have been estimated using the sequential two-step modeling (TSM) approach, in which primary models are fitted to the microbial growth data, and then secondary models are fitted to the primary model parameters to represent their dependence with the environmental variables (e.g., temperature). The Optimal Experimental Design (OED) approach allows reducing the experimental workload and costs, and the improvement of model identifiability because primary and secondary models are fitted simultaneously from non-isothermal data. Lactobacillus viridescens was selected to this study because it is a lactic acid bacterium of great interest to meat products preservation. The objectives of this study were to estimate the growth parameters of L. viridescens in culture medium from TSM and OED approaches and to evaluate both the number of experimental data and the time needed in each approach and the confidence intervals of the model parameters. Experimental data for estimating the model parameters with TSM approach were obtained at six temperatures (total experimental time of 3540h and 196 experimental data of microbial growth). Data for OED approach were obtained from four optimal non-isothermal profiles (total experimental time of 588h and 60 experimental data of microbial growth), two profiles with increasing temperatures (IT) and two with decreasing temperatures (DT). The Baranyi and Roberts primary model and the square root secondary model were used to describe the microbial growth, in which the parameters b and Tmin (±95% confidence interval) were estimated from the experimental data. The parameters obtained from TSM approach were b=0.0290 (±0.0020) [1/(h0.5°C)] and Tmin=-1.33 (±1.26) [°C], with R2=0.986 and RMSE=0.581, and the parameters obtained with the OED approach were b=0.0316 (±0.0013) [1/(h0.5°C)] and Tmin=-0.24 (±0.55) [°C], with R2=0.990 and RMSE=0.436. The parameters obtained from OED approach presented smaller confidence intervals and best statistical indexes than those from TSM approach. Besides, less experimental data and time were needed to estimate the model parameters with OED than TSM. Furthermore, the OED model parameters were validated with non-isothermal experimental data with great accuracy. In this way, OED approach is feasible and is a very useful tool to improve the prediction of microbial growth under non-isothermal condition.


Asunto(s)
Microbiología de Alimentos/métodos , Conservación de Alimentos , Almacenamiento de Alimentos , Lactobacillus/crecimiento & desarrollo , Productos de la Carne/microbiología , Modelos Biológicos , Recuento de Colonia Microbiana , Cinética , Modelos Teóricos , Proyectos de Investigación , Temperatura
17.
J Med Chem ; 59(19): 8848-8858, 2016 10 13.
Artículo en Inglés | MEDLINE | ID: mdl-27564419

RESUMEN

The potent MCHR1 in vitro and in vivo antagonist activity of a series of cyclic tertiary alcohols derived from compound 2b is described. Subsequent pharmacokinetic and pharmacodynamic studies identified BMS-814580 (compound 10) as a highly efficacious antiobesity agent with a relatively clean in vitro and in vivo safety profile.


Asunto(s)
Fármacos Antiobesidad/química , Fármacos Antiobesidad/uso terapéutico , Obesidad/tratamiento farmacológico , Pirimidinas/química , Pirimidinas/uso terapéutico , Receptores de Somatostatina/antagonistas & inhibidores , Animales , Fármacos Antiobesidad/farmacocinética , Fármacos Antiobesidad/farmacología , Perros , Halogenación , Humanos , Macaca fascicularis , Masculino , Ratones , Pirimidinas/farmacocinética , Pirimidinas/farmacología , Ratas , Receptores de Somatostatina/metabolismo , Relación Estructura-Actividad
18.
Foodborne Pathog Dis ; 13(8): 462-7, 2016 08.
Artículo en Inglés | MEDLINE | ID: mdl-26859536

RESUMEN

During the last decade, a specific strain of Salmonella Enteritidis (named SE86) has been identified as the major etiological agent responsible for salmonellosis in the State of Rio Grande do Sul, Southern Brazil, and the main food vehicle was homemade mayonnaise (HM). This study aimed to model the growth prediction of SE86 on HM under isothermal and nonisothermal conditions. SE86 was inoculated on HM and stored at 7, 10, 15, 20, 25, 30, and 37°C. Growth curves were built by fitting data to the Baranyi's DMFit, generating r(2) values greater than 0.98 for primary models. Secondary model was fitted with Ratkowsky equation, generating r(2) and root mean square error values of 0.99 and 0.016, respectively. Also, the growth of SE86 under nonisothermal conditions simulating abuse temperature during preparation, storage, and serving of HM was studied. Experimental data showed that SE86 did not grow on HM at 7°C for 30 days. At 10°C, no growth was observed until approximately 18 h, and the infective dose (assumed as 10(6) CFU/g) was reached after 8.1 days. However, the same numbers of SE86 were attained after 6 hours at 37°C. Experimental data demonstrated shorter lag times than those generated by ComBase Predictive Models, suggesting that SE86 is very well adapted for growing on HM. SE86 stored under nonisothermal conditions increased population to reach about 10(6) CFU/g after approximately 30 hours of storage. In conclusion, the developed model can be used to predict the growth of SE86 on HM under various temperatures, and considering this pathogen, HM can be produced if safe eggs are used and HM is stored below 7°C.


Asunto(s)
Huevos/microbiología , Calor , Intoxicación Alimentaria por Salmonella/microbiología , Brasil , Condimentos/microbiología , Medios de Cultivo , Brotes de Enfermedades , Manipulación de Alimentos/métodos , Microbiología de Alimentos , Conservación de Alimentos/métodos , Humanos , Salmonella enteritidis/crecimiento & desarrollo , Solanum tuberosum/microbiología
19.
Bioorg Med Chem Lett ; 25(20): 4412-8, 2015 Oct 15.
Artículo en Inglés | MEDLINE | ID: mdl-26386604

RESUMEN

Non-basic azolotriazinones were explored using an empirical free brain exposures-driven approach to identify potent MCHR1 antagonists for evaluation in in vivo efficacy studies. An optimized lead from this series, 1j (rMCHR1 Ki=1.8 nM), demonstrated a 6.9% reduction in weight gain relative to vehicle in a rat model at 30 mg/kg after 4 days of once-daily oral treatment as a glycine prodrug. Despite a promising efficacy profile, an assessment of the biliary toxicity risk of this compound rendered this compound non-progressible.


Asunto(s)
Encéfalo/efectos de los fármacos , Obesidad/tratamiento farmacológico , Receptores de Somatostatina/antagonistas & inhibidores , Triazinas/farmacología , Animales , Encéfalo/metabolismo , Relación Dosis-Respuesta a Droga , Humanos , Estructura Molecular , Obesidad/metabolismo , Ratas , Relación Estructura-Actividad , Triazinas/administración & dosificación , Triazinas/química
20.
Bioorg Med Chem Lett ; 25(14): 2793-9, 2015 Jul 15.
Artículo en Inglés | MEDLINE | ID: mdl-26022839

RESUMEN

Our investigation of the structure-activity and structure-liability relationships for dihydropyrrolopyrazol-6-one MCHR1 antagonists revealed that off-rate characteristics, inferred from potencies in a FLIPR assay following a 2 h incubation, can impact in vivo efficacy. The in vitro and exposure profiles of dihydropyrrolopyrazol-6-ones 1b and 1e were comparable to that of the thienopyrimidinone counterparts 41 and 43 except for a much faster MCHR1 apparent off-rate. The greatly diminished dihydropyrrolopyrazol-6-one anti-obesity response may be the consequence of this rapid off-rate.


Asunto(s)
Fármacos Antiobesidad/química , Pirazoles/química , Receptores de Somatostatina/antagonistas & inhibidores , Animales , Fármacos Antiobesidad/farmacocinética , Fármacos Antiobesidad/farmacología , Fármacos Antiobesidad/uso terapéutico , Semivida , Humanos , Obesidad/tratamiento farmacológico , Unión Proteica , Pirazoles/farmacocinética , Pirazoles/farmacología , Pirazoles/uso terapéutico , Ratas , Ratas Sprague-Dawley , Receptores de Somatostatina/metabolismo , Relación Estructura-Actividad , Pérdida de Peso/efectos de los fármacos
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