Suchergebnisse

The present work evaluated the antimicrobial potential of the ethanolic extract of jambu mawar [Syzygium jambos (L.) Alston] leaves against various foodborne pathogens and spoilage microorganisms via the disc diffusion assay (DDS) and the time-kill curve assay. These microorganisms included bacteria (Klebsiella pneumoniae ATCC13773, Listeria monocytogenes ATCC19112, Proteus mirabilis ATCC21100, Pseudomonas aeruginosa ATCC9027, Staphylococcus aureus ATCC29737, and Vibrio parahaemolyticus ATCC17802), yeasts (Candida albicans ATCC10231, C. krusei ATCC32196, C. glabrata ATCC2001, and C. parapsilosis ATCC22019), and moulds (Aspergillus fumigatus ATCC26430, A. niger ATCC9029, Rhizopus oligosporus ATCC22959, and R. oryzae ATCC22580). The inhibition zone of DDA ranged from 7.00 ± 0.23 to 10.25 ± 0.29 mm. The minimum inhibitory concentration (MIC) and minimum bactericidal/fungicidal (MBC/MFC) of the ethanolic leaf extract were obtained at the concentrations of 0.01 to 2.50 and 0.01 to 5.00 mg/mL, respectively. The time-kill curve assay showed that except for P. mirabilis, other microorganisms were completely killed at MIC concentrations ranging from 0.5 to 4× MIC. In comparison, P. mirabilis showed a growth reduction of > 3 log10 CFU/mL for 4 h. Meanwhile, the conidial germination of A. fumigatus was fully inhibited at 0.5× MIC. Though not fully inhibited, the ethanolic leaf extract significantly reduced the conidial germination of A. niger, R. oryzae, and R. oligosporus to 7.0, 7.0, and 11.0%, respectively. Overall, the ethanolic leaf extract of S. jambos exhibited antimicrobial activity against foodborne pathogens and spoilage microorganisms.

VIN03-007-C2-1, AGL2003-01295, AGL2004-00978, Consolider-Ingenio 2010 CSD2007-0063, AGL2010-21009, and AGL2014-58205-REDC from the Spanish Government-FEDER. ; Peer reviewed

[SPA] Los tratamientos térmicos son el proceso de conservación más ampliamente utilizado en la industria alimentaria. Podría decirse que casi todos los alimentos reciben, al menos, un tratamiento térmico durante su manufacturación. Los objetivos de este trabajo fueron determinar el comportamiento de los microorganismos en condiciones isotérmicas y anisotérmicas(tanto en estático como en continuo), determinar el uso correcto de la combinación de calor y antimicrobianos naturales (tecnología de barreras) y encontrar los genes involucrados en la respuesta a los tratamientos térmicos. El uso de la tecnología de barreras se basa en aplicarlas de forma correcta. En este estudio se encontró que aplicar los compuestos antimicrobianos durante el tratamiento térmico no tenía efecto sobre la inactivación del microorganismo, mientras que su aplicación después del mismo, resultó en una reducción significativa del tiempo de tratamiento. El intercambiador de calor usado en esta investigación permite determinar el comportamiento de los microorganismos de forma más real. Los resultados obtenidos muestran que un ligero incremento en la velocidad de calentamiento resulta en una mayor inactivación. La síntesis de novo de proteínas y el uso de la cisteína para la estabilización de las proteínas celulares son mecanismos clave en la termorresistencia de C. sakazakii. [ENG] Thermal treatments are the most widely preservation technique used in the food industry. Almost, all food products are heated at least once. The objectives of this study were to determine the behavior of microorganisms under isothermal and non-isothermal heat treatments, to determine the microbial inactivation during a continuous heating process, to find the best balanced application of heat and natural antimicrobials (hurdles), and to determine the genes that could be involved in heat resistance. The basis of the hurdle technology is its correct use in the accurate way. Results show that the application of the natural antimicrobials in the heating medium do not have effect in the inactivation of the microorganism, while its application just before the thermal treatment results in greater inactivation, leading to a reduction of the treatment time. Results on the heat exchanger show that under non-isothermal treatments, a slight increase in the heating rate results in greater inactivation of microorganisms at the end of the process. The de novo protein synthesis and cysteine uptake for protein stabilization are key process in the heat resistance of C. sakazakii. ; The financial support of this research was provided by the Ministry of Science and Technology of the Spanish Government and European Regional Development Fund (ERDF) through Project AGL- 2010-19775. J.P Huertas is grateful to the Spanish Ministry of Science and Innovation for his fellowship (BES-2011-046580).

Dekkera bruxellensis is the main reason for spoilage in the wine industry. It renders the products unacceptable leading to large economic losses. Fluorescence In Situ Hybridisation (FISH) technique has the potential for allowing its specific detection. Nevertheless, some experimental difficulties can be encountered when FISH technique is applied in the wine environment (e.g. matrix and cells autofluorescence, fluorophore inadequate selection and probes low specificity to the target organisms). An easy and fast in-suspension RNA-FISH procedure was applied for the first time for identifying D. bruxellensis in wine. A previously designed RNA-FISH probe to detect D. bruxellensis (26S D. brux.5.1) was used and the matrix and cells fluorescence interferences, the influence of three fluorophores in FISH performance and the probe specificity were evaluated. The results revealed that to apply RNA-FISH technique in the wine environment a red-emitting fluorophore should be used. Good probe performance and specificity was achieved with 25% of formamide. The resulting RNA-FISH protocol was applied in wine samples artificially inoculated with D. bruxellensis. This spoilage microorganism was detected in wine at cell densities lower than those associated with phenolic off-flavours. Thus, the RNA-FISH procedure described in this work represents an advancement to facilitate early detection of the most dangerous wine spoilage yeast and, consequently, to reduce the economic losses caused by this yeast to the wine industry. ; This work was co-financed by Foundation for Science and Technology (FCT) and the European Union through the European Regional Development Fund ALENTEJO 2020 through the projects PTDC/BBB-IMG/0046/2014 and ALT20-03-0145-FEDER-000015, respectively. Marina González-Pérez acknowledges FCT for the economic support through the post-doctoral grant SFRH/BPD/100754/2014.

The shelf life of milk and milk derivatives is directly related to the microbiological quality of refrigerated raw milk. Spoilage microorganisms with proteolytic and/or lipolytic properties are primarily responsible for the decrease in the quality of milk, which is reflected in the shelf life of pasteurized milk and all derivatives. The aim of this study was to determine the spoilage microbial load of refrigerated raw milk from the northeast and southern regions of Brazil, which have different climatic and technological conditions of production. We evaluated 46 samples of milk from the state of Paraná in the southern region, and 10 samples of milk from the state of Maranhão in the northeast region, totaling 56 samples collected from November 2013 to November 2014. The producers of Paraná were divided into large (20) or small (26) according to the average daily production. All producers of Maranhão were considered small (<500L/day). The proteolytic and lipolytic microorganism counts were conducted in milk agar and tributyrin agar, respectively. Milk from the large producers of Paraná had average counts of 1.4 × 104 CFU/mL for proteolytic microorganisms and 1.2 × 103 CFU/mL for lipolytics microorganisms, significantly (p <0.05) lower than the small producers in the same state, and the producers of Maranhão. Producers of Maranhao had counts of 1.1 × 105 CFU/mL for proteolytic microorganisms and 2 × 105 CFU/mL for lipolytic microorganisms, with the proteolytic count significantly lower than that of small Paraná producers. The amount of proteolytic and lipolytic spoilage microorganisms in milk is influenced by the adaptation of the microorganisms to cold, promoted by the cooling of milk, which is practiced less frequently in the country's northeastern region. The amount of spoilage microorganisms is also affected by the implementation of milking hygiene practices, which reduce contamination. Such practices are more frequently and efficiently implemented among large producers with more advanced technology, which can improve the microbiological quality of raw milk, thus increasing the shelf life of pasteurized milk, and reducing problems in UHT milk as well as milk derivatives.

Aerobic bacterial spores are an important group of microorganisms in raw milk. These microbes are thermoduric, whereas the vegetative forms are thermophilic, thermoduric and psychrotrophic and reduce the shelf life of pasteurized milk. In Brazil, there are a lack of studies on the load of aerobic spores in raw milk; thus, little is known about the spoilage activity of these organisms. The aim the present study was to quantify the aerobic spores in Brazilian refrigerated raw milk of dairy region of Castro, Paraná state, assess the potential proteolytic and/or lipolytic isolates and identify the microorganisms derived from the germination. Twenty milk samples were evaluated, and the aerobic spore count was performed after plating the samples following heat treatment at 80°C for 12 min. The activity proteolytic and lipolytic isolates were evaluated through subculture on milk agar and tributyrin agar, respectively, and these microorganisms were identified using partial 16S rRNA gene sequences that were compared through GenBank. The aerobic spore counts ranged from 1 to 3.7 log CFU.mL-1, with a mean of 1.75 (± 0.59) log CFU.mL-1. After spore germination, 137 aerobic bacterial isolates were obtained, 40 of which (29.2%) showed milk spoilage activity. Among these, 31 isolates (77.5%) were proteolytic and lipolytic, seven isolates (17.5%) were exclusively lipolytic and two isolates (5%) were only proteolytic. Based on the 16S rRNA gene analysis, Bacillus licheniformis (55%), Bacillus spp. (27.5%), Paenibacillus spp. (7.5%), Bacillus pumilus (5%), Bacillus circulans (2.5%) and Brevibacillus spp. (2.5%) were identified. Studies of Brazilian raw milk microbiota have not yet described B. circulans which are frequently detected in milk from other countries. Among the 22 B. licheniformis isolates, 21 microbes (95.5%) showed proteolytic and lipolytic activity, and one isolate (4.5%) exhibited only proteolytic activity. The two B. pumilus isolates were proteolytic and lipolytic, whereas the B. circulans isolate was only lipolytic. Among the 11 Bacillus spp. isolates, eight isolates (72.7%) were proteolytic and lipolytic, one isolate (9.1%) was proteolytic and the other two isolates (18.2%) were lipolytic. The three Paenibacillus spp. and Brevibacillus spp. isolates were primarily lipolytic. Therefore, to extend the shelf life of pasteurized milk, preventive measures must be adopted to reduce contamination with spores because one-third of these microorganisms exhibited proteolytic and/or lipolytic activity.

ABSTRACT: In this study, the kinetic parameters of mesophilic, psychrotrophic and lactic acid bacteria in vacuum-packed beef at 1 °C and 4 °C were estimated from experimental growth curves produced by samples stored during 21 and 60 days, respectively. In a separate experiment, the survival of multidrug resistant (MDR) Salmonella enterica O:4,5 at 1°C was also characterized. The shelf-life of vacuum-packed beef stored at 4 °C was estimated at 16.1 days (95% CI: 14.8 - 17.3 days), whereas at 1 °C it was longer than 21 days because the mesophiles count estimated towards the end of the experiment was 12.5 ln CFU.g-1 (95% CI: 11.8 - 13.3 ln CFU.g-1) which is lower than the shelf-life reference value. At 1 °C, inoculated Salmonella was reduced in 6.61 ln CFU.g-1 (2.87 log CFU.g-1). These results demonstrated the importance of establishing in legislation, especially in Brazil, standard values of deteriorating microorganisms in beef for maintaining product quality.

AbstractAnalysis of plant pollen can provide valuable insights into the existing spectrum of microorganisms in the environment. When harvesting bee-collected pollen as a dietary supplement for human consumption, timely preservation of the freshly collected pollen is fundamental for product quality. Environmental microorganisms contained in freshly collected pollen can lead to spoilage by degradation of pollen components. In this study, freshly collected bee pollen was sampled at different locations and stored under various storage conditions to examine the hypothesis that storage conditions may have an effect on the composition of microorganisms in pollen samples. The samples were analyzed using 16S and 18S amplicon sequencing and characterized by palynological analysis. Interestingly, the bacterial communities between pollen samples from different locations varied only slightly, whereas for fungal community compositions, this effect was substantially increased. Further, we noticed that fungal communities in pollen are particularly sensitive to storage conditions. The fungal genera proportion Cladosporium and Mycosphaerella decreased, while Zygosaccharomyces and Aspergillus increased during storage. Aspergillus and Zygosaccharomyces fractions increased during storage at 30 °C, which could negatively impact the pollen quality if it is used as a dietary supplement.

Food spoilage is caused by the development of microorganisms, biogenic amines, and other harmful substances, which, when consumed, can lead to different health problems. Foodborne diseases can be avoided by assessing the safety and freshness of food along the production and supply chains. The routine methods for food analysis usually involve long analysis times and complex instrumentation and are performed in centralized laboratories. In this context, sensors based on screen-printed electrodes (SPEs) have gained increasing importance because of their advantageous characteristics, such as ease of use and portability, which allow fast analysis in point-of-need scenarios. This review provides a comprehensive overview of SPE-based sensors for the evaluation of food safety and freshness, focusing on the determination of bacteria and biogenic amines. After discussing the characteristics of SPEs as transducers, the main bacteria, and biogenic amines responsible for important and common foodborne diseases are described. Then, SPE-based sensors for the analysis of these bacteria and biogenic amines in food samples are discussed, comparing several parameters, such as limit of detection, analysis time, and sample type. ; This work was supported by UIDB/50006/2020 and UIDP/50006/2020 with funding from the Fundação para a Ciência e a Tecnologia (FCT)/the Ministério da Ciência, Tecnologia e Ensino Superior (MCTES) through national funds. The authors also thank FCT and the EU for funding through the projects: FishBioSensing—Portable electrochemical (bio)sensing devices for safety and quality assessment of fishery products (02/SAICT/2016, POCI-01-0145-FEDER-023817), PTDC/QUI-QAN/30735/2017—TracAllerSens—Electrochemical sensors for the detection and quantification of trace amounts of allergens in food products (POCI-01-0145-FEDER-030735), and PTDC/ASP-PES/29547/2017—CECs(Bio)Sensing—(Bio)sensors for assessment of contaminants of emerging concern in fishery commodities (POCI-01-0145-FEDER-029547), supported by national funds by FCT/MCTES and co-supported by Fundo Europeu de Desenvolvimento Regional (FEDER) through COMPETE 2020—Programa Operacional Competitividade e Internacionalização. E. Costa-Rama thanks the Government of Principado de Asturias and Marie Curie-Cofund Actions for the post-doctoral grant "Clarín-Cofund" ACA17-20. R. Torre is grateful to FCT for her PhD grant (SFRH/BD/143753/2019), financed by POPH–QREN–Tipologia 4.1–Formação Avançada, subsidized by FSE and MCTES. ; info:eu-repo/semantics/publishedVersion

Indigenous fermented foods (IFFs) have a long history in Africa and are embedded in cultural norms and practices. Typically, these foods are produced at a small or household scale using indigenous processing technologies. In addition, limited knowledge of good manufacturing and handling practices can lead to production under unhygienic conditions. This results in variations in the quality and safety attributes of IFFs, as spoilage and pathogenic bacteria can be introduced at any stage of the value chain. These foods have an important role in the African diet and can contribute to food security by increasing the availability of cheap, nutritious food and supporting livelihoods. However, the presence of foodborne pathogens and antibiotic-resistant bacteria in IFFs may constitute a health risk to consumers. Therefore, this review presents an overview of the microorganisms associated with IFFs from Africa, focusing on microbial food safety hazards. African indigenous fermented foods offer a vast genetic potential of undiscovered strains that possess valuable technical characteristics. However, IFFs may also serve as vehicles of pathogenic and antibiotic-resistant bacteria and genetic determinants. Significant research and data gaps exist regarding the microbiological safety of these food products, which warrant urgent attention. We propose practical solutions for improving the safety of African IFFs requiring action and collaboration from all stakeholders, including researchers, producers, governmental regulatory bodies, and consumers.

Indigenous fermented foods (IFFs) have a long history in Africa and are embedded in cultural norms and practices. Typically, these foods are produced at small or household scale using indigenous processing technologies. In addition, limited knowledge of good manufacturing and handling practices can lead to production under unhygienic conditions. This results in variations in the quality and safety attributes of IFFs, as spoilage and pathogenic bacteria can be introduced at any stage of the value chain. These foods have an important role in the African diet and can contribute to food security by increasing the availability of cheap, nutritious food and supporting livelihoods. However, the presence of foodborne pathogens and antibiotic-resistant bacteria in IFFs may constitute a health risk to consumers. Therefore, this review presents an overview of the microorganisms associated with IFFs from Africa, focusing on microbial food safety hazards. African indigenous fermented foods offer a vast genetic potential of undiscovered strains that possess valuable technical characteristics. However, IFFs may also serve as vehicles of pathogenic and antibiotic-resistant bacteria and genetic determinants. Significant research and data gaps exist regarding the microbiological safety of these food products, which warrant urgent attention. We propose practical solutions for improving the safety of African IFFs requiring action and collaboration from all stakeholders, including researchers, producers, governmental regulatory bodies, and consumers.