Prevalence of Listeria species in some foods and their rapid identification

Purpose: To investigate the occurrence of Listeria spp., (particularly L. monocytogenes ), in different foods and to compare diagnostic tools for their identification at species level. Methods: Samples of high protein foods such as raw meats and meat products and including beef products, chicken, fish and camel milk were analysed for the presence of Listeria spp. The isolates were characterised by morphological and cultural analyses, and confirmed isolates were identified by protein profiling and verified using API Listeria system. Protein profiling by SDS-PAGE was also used to identify Listeria spp. Results: Out of 40 meat samples, 14 (35 %) samples were contaminated with Listeria spp., with the highest incidence (50 %) occurring in raw beef products and raw chicken. Protein profiling by SDSPAGE was used to identify Listeria spp. The results were verified with API Listeria system. Approximately 25 % of the identified isolates were Listeria seeligeri , Listeria welshimeri , and Listeria grayi (three positive samples), while 16.66 % of the isolates were Listeria monocytogenes (two positive samples); 16.6 % of the isolates were Listeria innocua (two positive samples), while 8.3 % of the isolates were Listeria ivanovii (one positive sample). Conclusion: High protein foods contain different types of Listeria species; whole-cell protein profiles and API Listeria system can help in the identification of Listeria at the species level.

Determination of acrylamide levels in selected commercial and traditional foods in Syria

Purpose: To determine acrylamide (AA) levels in different brands of commercial and traditional foodstuffs available in Syria by ultra-performance liquid chromatography-mass spectrometery (UPLCMS). Methods: A total of 63 samples were analyzed. Food samples were defatted by hexane and then extracted with methanol 98 % in a vortex mixer. Thereafter, Carrez I and Carrez II were added to precipitate proteins from the co-extractives and then centrifuged to obtain a clear aqueous extract that was evaporated to dryness. The extract was dissolved in 1 mL of water, eluted through a preconditioned Oasis HLB cartridge and then filtered. The filtrate was analyzed by UPLC-MS/MS to determine AA content. Results: Among the commercial foods tested, the highest acrylamide quantity was found in potato products (396 ± 3.59 – 1844 ± 5.29 μg kg−1) and the lowest in corn products (183 ± 2.64 – 366 ± 4.58 μg kg−1). This was followed by biscuits (57 ± 2.64 – 1433 ± 2.51 μg kg−1), breakfast cereals (121 ± 8.73 – 245 ± 3.60 μg kg−1), bread (119 ± 1.73 – 263 ± 3.60 μg kg−1) and then coffee (113 ± 2.64 - 64 ± 3.05 μg kg−1). Regarding traditional foods, the highest level of AA was found in AL- Mshabak (481 ± 2.08 μg kg−1) and AL-Awamat (421 ± 2.64 μg kg−1) followed by AL-Namora (282 ± 4.35 μg kg−1) and AL-Kenafa (242 ± 2.64 μg kg−1). It was also observed that the lowest amount of AA was in fried bread (230 μg kg−1), AL-Fatayer (192 ± 3.51 μg kg−1) and AL-Baqlawa (172 ± 4.35 μg kg−1) while Eid Aqras (130 ± 4.58 μg kg−1) and AL-Brazeq (167 ± 3.78 μg kg−1) contained the least amount of AA. Conclusion: The results indicate that the highest levels of AA are found in the most commonly consumed foods. There was significant difference (p < 0.05) in AA levels among different food items and within different brands of the same product.

Un modelo de gestión de la creatividad que promueva la innovación en las organizaciones: caso Griffith Foods S.A.S.

En la actualidad las organizaciones se encuentran inmersas en un ambiente en extremo cambiante y competitivo que las obliga a estar siempre a la vanguardia y hacer de la innovación un proceso sistemático, que se alimenta no solo de las prospectivas científico-tecnológicas y la inteligencia competitiva, sino también del potencial creativo de su gente -- Pero ¿cómo se potencializa, entonces, la innovación en las organizaciones a partir de la gestión de la creatividad con sus colaboradores? Ése fue el gran interrogante que se planteó en este trabajo de investigación y para contribuir a su solución se diseñó y validó un modelo teórico conceptual que cruza variables que afectan la creatividad y potencializan la innovación, en el marco de posturas de autores reconocidos como Kerrie Unsworth, que trabaja diferentes tipos de creatividad en las personas a través de una matriz que relaciona los problemas de las organizaciones con el nivel de compromiso de los empleados, y Teresa Amabile, con su modelo de creatividad organizacional para la innovación, que permite identificar variables como la motivación, el engagement el liderazgo y la cultura organizacional, entre otras -- Dichas posturas se constituyeron en elementos importantes por considerar para la construcción del modelo, que con posterioridad se validó en dos momentos: el primero con expertos en el tema por medio del método Delphi y el segundo en la organización Griffith Foods S. A. S., a través de una face validity con los gerentes de la compañía -- Con estas validaciones se ajustó el modelo, lo que permitió incorporar otra variable que no se había considerado, el conocimiento, y se identificó la posibilidad de aplicarlo en las diferentes unidades de negocio en la organización -- Por último, como aplicación experimental del mismo, se formularon las recomendaciones para que fuese implementado, no sólo en la organización Griffith Foods S. A. S. como objeto de estudio, sino en otras que deseen potencializar la innovación a partir de la creatividad en las personas y en sus equipos de trabajo

From field to fermentation: characterisation and application of non-dairy cultures in dairy foods

This thesis investigates the phenotypic and genotypic diversity of non-dairy L. lactis strains and their application to dairy fermentations. A bank of non-dairy lactococci were isolated from grass, vegetables and the bovine rumen. Subsequent analysis of these L. lactis strains revealed seven strains to possess cremoris genotypes which did not correlate with their observed phenotypes. Multi-locus sequence typing (MLST) and average nucleotide identity (ANI) highlighted the genetic diversity of lactis and cremoris subspecies. The application of these non-dairy lactococci to cheese production was also assessed. In milk, non-dairy strains formed diverse volatile profiles and selected strains were used as adjuncts in a mini Gouda-type cheese system. Sensory analysis showed non-dairy strains to be strongly associated with the development of off-flavours and bitterness. However, microfluidisation appeared to reduce bitterness. A novel bacteriophage, ɸL47, was isolated using the grass isolate L. lactis ssp. cremoris DPC6860 as a host. The phage, a member of the Siphoviridae, possessed a long tail fiber, previously unseen in dairy lactococcal phages. Genome sequencing revealed ɸL47 to be the largest sequenced lactococcal phage to date and owing to the high % similarity with ɸ949, a second member of the 949 group. Finally, to identify and characterise specific genes which may be important in niche adaptation and for applications to dairy fermentations, comparative genome sequence analysis was performed on L. lactis from corn (DPC6853), the bovine rumen (DPC6853) and grass (DPC6860). This study highlights the contribution of niche specialisation to the intra-species diversity of L. lactis and the adaptation of this organism to different environments. In summary this thesis describes the genetic diversity of L. lactis strains from outside the dairy environment and their potential application in dairy fermentations.

Macroalgae and commercial macroalgal polysaccharides as potential functional ingredients in muscle foods

Ulva rigida (UR) and Palmaria palmata (PP) were included in farmed Atlantic salmon diets at levels of 0-15% for 19 and 16 weeks, respectively. Quality and shelf-life parameters of salmon fillets stored in modified atmosphere packs (MAP) (60% N2 : 40% CO2) at 4ºC were compared to controls fed astaxanthin. Salmon fillets were enhanced with a yellow/orange colour. Proximate composition, pH and lipid oxidation were unaffected by dietary UR and PP. Salmon fed 5% UR and 5-15% PP did not influence sensory descriptors (texture, odour, oxidation flavour and overall acceptability) of cooked salmon fillets. Pig diets were supplemented with commercial wet- and spray-dried macroalgal (Laminaria digitata) polysaccharide extracts containing laminarin (L, 500 mg/kg feed) and fucoidan (F, 420 mg/kg feed) (L/F-WS, L/F-SD) for 3 weeks and quality and shelf-life parameters of fresh pork steaks (longissimus thoracis et lumborum) stored in MAP (80% O2 : 20% CO2) were examined. Level (450 or 900 mg L and F/kg feed) and duration (3 or 6 weeks) of dietary L/F-WS and mechanisms of antioxidant activities in pork were investigated. L/F-WS reduced (p < 0.05) lipid oxidation and lowered levels of saturated fatty acids in fresh pork after 3 weeks feeding. L/F-SD was added directly to mince pork (0.01 - 0.5%) and quality and shelf-life parameters of fresh pork patties stored in MAP (80% O2 : 20% CO2) were assessed. Direct addition of the L/F-SD increased levels of lipid oxidation and decreased surface redness (a* values) of fresh pork patties. Lipid oxidation was reduced in cooked patties due to the formation of Maillard reaction products. Cooked pork patties containing L/F-SD were subjected to an in vitro digestion and a cellular transwell model to confirm bioaccessibility and uptake of antioxidant compounds. In mechanistic studies, fucoidan demonstrated antiand pro-oxidant activities on muscle lipids and oxymyoglobin, respectively.

Análisis del sector del food service a partir del modelo de competitividad de Michael Porter para determinar la viabilidad de incursión de la empresa Bakery Service Foods

Las Mipymes son un componente fundamental para el desarrollo económico y social de cualquier país, en especial de un país como Colombia en donde representan el 99,9% de las empresas actualmente constituidas, concentrando el 81% de los empleados a nivel nacional (Fedesarrollo, 2013). Aunque juegan un papel protagónico en la economía colombiana, las Mipymes aún deben recorrer un camino extenso para poder explotar todo el potencial con el que cuentan, puesto que presentan un alto índice de mortandad empresarial en los primeros años de funcionamiento, esto evidenciado en los resultados del estudio GEM (Global Entrepreneurship Monitor, 2009) en donde se encontró que sólo el 12,61% de los negocios lograron superar los 42 meses de permanencia en el mercado (El País, 2010) principalmente a causa de la ausencia de una planeación estratégica de largo plazo que les permita a los negocios emprendedores del país alcanzar la competitividad. Si bien es cierto que crear empresa es relativamente sencillo, son múltiples los retos tanto internos como externos que deben enfrentar las organizaciones para poder alcanzar una etapa de madurez empresarial, sobre todo en los primeros años de funcionamiento que son los más críticos y decisivos para el futuro de cualquier empresa, es por esto que se hace indispensable emplear estrategias que les permitan ser sostenibles a largo plazo, en un entorno altamente competitivo por empresas tanto nacionales como internacionales, siendo este uno de los propósitos fundamentales al que deberían apostar los empresarios colombianos para crear un impacto positivo en la sociedad y aportar a la competitividad nacional. Bakery Service Foods, es una empresa dedicada a la comercialización y distribución de insumos de panadería con sede en el barrio Carvajal en la ciudad de Bogotá. Desde su constitución, el 29 de diciembre de 2008, la empresa ha buscado posicionarse en un mercado en donde tanto empresas grandes como Grasco, Grupo Team, Sigra, Duquesa, Conaceites, Alvarado, Aceites Finos; así como microempresas sin infraestructura ni solidez económica, componen un entorno altamente competitivo y hacinado que representa un desafío para una pequeña empresa familiar que no cuenta con un músculo financiero significativo. Por otra parte, Bakery Service Foods a traviesa por un período de alta incertidumbre debido a que el proveedor que representa el 85% de las ventas de los productos a los cuales representan, FANAGRA S.A, atraviesa por una completa reestructuración debido a la venta de dicha empresa a una multinacional suiza. Esta situación representa un alto riesgo para la compañía y exige que se emprendan acciones oportunas que les permitan reducir la alta dependencia en un único proveedor. Teniendo en cuenta que una de las ambiciones desde la fundación de la compañía ha sido incursionar y ser una empresa competitiva en el mercado de Food Service, que perdure en el tiempo, ¿Qué tan viable es diversificar el portafolio de la empresa Bakery Service Foods (BSF) en el mercado Food Service? Con este proyecto se busca diseñar una propuesta de diversificación de portafolio para la empresa Bakery Service Foods (BSF) analizando el mercado Food Service, por medio del modelo de Ventaja Competitiva de Michael Porter; lo anterior, con el propósito de que la empresa se consolide en este mercado como un aliado estratégico para sus clientes y representados, y con un modelo de negocio sostenible a largo plazo. Finalmente, se espera que a través de la propuesta de mejora para Bakery Service Foods, se afiancen los conocimientos administrativos obtenidos durante el pregrado en Administración de Empresas, aplicando satisfactoriamente las herramientas, metodologías y bases conceptuales adquiridas, para enriquecer el proceso de aprendizaje profesional y aportar valor a una empresa colombiana desde el mercado de Food Service.

Oral food perception and polyphenol-rich foods acceptance - the importance of knowing individuals saliva characteristics for promoting consumption

Polyphenols are widely present in fruits, vegetables, cereals and beverages. Their study gained scientific interest because of their beneficial effects on health. Although there is currently no official dietary recommendation for polyphenol intake, health professionals recommend the consumption of 5-8 daily portions of fruits and vegetables. This is not always achieved and, despite possible causes associated to practical schedule difficulties, the aversive bitter and astringent sensations associated to polyphenols may also lead to avoidance. As such, a better understanding on mechanisms responsible for differences among people, in polyphenol oral perception, is needed for promoting healthier choices. Saliva has been linked to polyphenol consumption. We have previously observed, in animal models, changes in salivary proteome induced by tannin-enriched diets. Moreover, differences in astringency perception were attributed to differences in salivary protein composition. In a recent experiment, we observed differences among individuals with dissimilar tannic-acid perception: people with high sensitivity for the oral sensations elicited by tannins have higher amounts of salivary cystatins and lower capacity to maintain their levels after tannic-acid ingestion. Additionally, and similarly to previous studies, salivary amylase was observed to be involved in tannin perception. In this presentation, oral cavity characteristics influencing the perception of polyphenol-containing foods will be discussed.

Application of Pulsed Electric Fields for the Modulation of Chemico-Physical Properties of Different Foods

Pulsed electric field technology is one of the most attractive new non-thermal technology thanks to its lower energy consumption and short treatment times. It consists of an electric treatment of short duration (from several ns to several ms) with electric field strengths from 0.1 to 80 kV/cm that lead to an increase in the permeability of the cell membrane. In this PhD thesis, PEF technology was investigated with the aim of improving mass transfer in plant and animal foods by using it alone or in combination with conventional food processes. Different methods of evaluating electroporation for optimizing PEF processing parameters were investigated. In this respect, the degree of membrane permeabilization in plant and animal food matrices was investigated using electrical impedance spectroscopy, current-voltage measurements and magnetic resonance imaging. The research findings provided useful insights and calls for critical choice of electroporation assessment methods for the selection of adequate PEF treatment conditions. It was outlined that the effect of electroporation is highly dependent on the properties of the food matrix and secondary phenomena occurring in the cell structure undergoing PEF treatment, such as the water re-distribution in the tissue due to the exchange of fluids between intra- and extra-cellular environments. This study also confirmed the great potential of combining PEF technology with conventional food processes, with the main purpose of improving the quality of the food material and accelerating the kinetics of mass transfers, in both plant and animal tissues. Consistent reduction of acrylamide formation in potato crisps was achieved by monitoring key PEF process parameters and subsequent manufacturing steps. Kiwifruit snacks showed a significant reduction in drying kinetics when pre-treated with PEF, while their quality was well maintained. Finally, the research results showed that PEF pre-treatments can shorten the brine process as well as the rehydration kinetics of fish muscles.

Microbiome and resitome and foods of animal origin

To ensure food safety and to prevent food-borne illnesses, rapid and accurate detection of pathogenic agents is essential. It has already been demonstrated that shotgun metagenomic sequencing can be used to detect pathogens and their antibiotic resistance genes in food. In the studies presented in this thesis, the application shotgun metagenomic sequencing has been applied to investigate both the microbiome and resistome of foods of animal origin in order to assess advantages and disadvantages of shotgun metagenomic sequencing in comparison to the cultural methods. In the first study, it has been shown that shotgun metagenomics can be applied to detect microorganisms experimentally spiked in cold-smoked salmon. Nevertheless, a direct correlation between cell concentration of each spiked microorganism and number of corresponding reads cannot be established yet. In the second and third studies, the microbiomes and resistomes characterizing caeca and the corresponding carcasses of the birds reared in the conventional and antibiotic free farms were compared. The results highlighted the need to reduce sources of microbial contamination and antimicrobial resistance not only at the farm level but also at the post-harvest one. In the fourth study, it has been demonstrated that testing a single aliquot of a food homogenate is representative of the whole homogenate because biological replicates displayed overlapping taxonomic and functional composition. All in all, the results obtained confirmed that the application of shotgun metagenomic sequencing represents a powerful tool that can be used in the identification of both spoilage and pathogenic microorganism, and their resistome in foods of animal origin. However, a robust relationship between sequence read abundance and concentration of colony-forming unit must be still established.

Selection of candidate probiotic strains from human microbial niches, for the development of tailored foods designed for specific consumers

My PhD project was intended, throughout the selection of probiotics from human milk and healthy vaginal environment, for the development of tailored fermented foods. According to this aim, several activities were carried out. The first one, concerning the isolation of Lactobacillus and Bifidobacterium strains from human milk to find new probiotic candidates to be included in food products showed promising results. Probiotics have been also proposed to improve female genital health and microbial strains isolated and connected with healthy vaginal ecosystem could be used to prevent or treat vaginal dysbiosis. In this context vaginal lactobacilli previously characterized for their technological features and antagonistic activity against several female uro-genital pathogens were investigated for their metabolic aptitude and additional probiotic features, showing interesting results hypothesizing their inclusion in foods. In addition, in order to preserve vaginal strains viability during food processing/digestion it was also evaluated the potential of microencapsulation by spray-drying. In this framework the results obtained were highly promising from the perspective of using encapsulated powders in food formulations. Another activity connected with the main idea to develop a food strategy for the administration of these vaginal strains was carried out. Lactobacillus crispatus BC4, was supplemented in a Squacquerone cheese, and its digestive fate was evaluated adopting SHIME® system. The results showed that during colonic fermentation, L. crispatus BC4 was metabolically active. Additionally, although probiotic delivery to humans has traditionally been associated with fermented dairy foods, recently the demand for non-dairy-alternatives as potential probiotics carrier is increasing. In this framework, my latest activity was connected with the development of fermented soy milks with encapsulated and non-encapsulated L. crispatus BC4 and L. gasseri BC9. The same fermented soy milks were also investigated for their nutritional qualities and after in vitro digestion for their specific functionality on post-menopausal fecal microbiota and protein bioaccessibility.

Low-density Lipoprotein Cholesterol And Radiotherapy-induced Carotid Atherosclerosis In Subjects With Head And Neck Cancer.

Radiotherapy (RT) is a risk factor for accelerated carotid artery atherosclerotic disease in subjects with head and neck cancer. However, the risk factors of RT-induced carotid artery remodeling are not established. This study aimed to investigate the effects of RT on carotid and popliteal arteries in subjects with head and neck cancer and to evaluate the relationship between baseline clinical and laboratory features and the progression of RT-induced atherosclerosis. Eleven men (age = 57.9 ± 6.2years) with head and neck cancer who underwent cervical bilateral irradiation were prospectively examined by clinical and laboratory analysis and by carotid and popliteal ultrasound before and after treatment (mean interval between the end of RT and the post-RT assessment = 181 ± 47 days). No studied subject used hypocholesterolemic medications. Significant increases in carotid intima-media thickness (IMT) (0.95 ± 0.08 vs. 0.87 ± 0.05 mm; p < 0.0001) and carotid IMT/diameter ratio (0.138 ± 0.013 vs. 0.129 ± 0.014; p = 0.001) were observed after RT, while no changes in popliteal structural features were detected. In addition, baseline low-density lipoprotein cholesterol levels showed a direct correlation with RT-induced carotid IMT change (r = 0.66; p = 0.027), while no other studied variable exhibited a significant relationship with carotid IMT change. These results indicate that RT-induced atherosclerosis is limited to the irradiated area and also suggest that it may be predicted by low-density lipoprotein cholesterol levels in subjects with head and neck cancer.

Yellowing And Bleaching Of Grey Hair Caused By Photo And Thermal Degradation.

Yellowing is an undesirable phenomenon that is common in people with white and grey hair. Because white hair has no melanin, the pigment responsible for hair colour, the effects of photodegradation are more visible in this type of hair. The origin of yellowing and its relation to photodegradation processes are not properly established, and many questions remain open in this field. In this work, the photodegradation of grey hair was investigated as a function of the wavelength of incident radiation, and its ultrastructure was determined, always comparing the results obtained for the white and black fibres present in grey hair with the results of white wool. The results presented herein indicate that the photobehaviour of grey hair irradiated with a mercury lamp or with solar radiation is dependent on the wavelength range of the incident radiation and on the initial shade of yellow in the sample. Two types of grey hair were used: (1) blended grey hair (more yellow) and (2) grey hair from a single-donor (less yellow). After exposure to a full-spectrum mercury lamp for 200 h, the blended white hair turned less yellow (the yellow-blue difference, Db(*) becomes negative, Db(*)=-6), whereas the white hair from the single-donor turned slightly yellower (Db(*)=2). In contrast, VIS+IR irradiation resulted in bleaching in both types of hair, whereas a thermal treatment (at 81 °C) caused yellowing of both types of hair, resulting in a Db(*)=3 for blended white hair and Db(*)=9 for single-donor hair. The identity of the yellow chromophores was investigated by UV-Vis spectroscopy. The results obtained with this technique were contradictory, however, and it was not possible to obtain a simple correlation between the sample shade of yellow and the absorption spectra. In addition, the results are discussed in terms of the morphology differences between the pigmented and non-pigmented parts of grey hair, the yellowing and bleaching effects of grey hair, and the occurrence of dark-follow reactions.

Morphological Aspects And Cox-2 Expression After Exposure To 780-nm Laser Therapy In Injured Skeletal Muscle: An In Vivo Study.

The effectiveness of low-level laser therapy in muscle regeneration is still not well known. To investigate the effects of laser irradiation during muscle healing. For this purpose, 63 rats were distributed to 3 groups: non-irradiated control group (CG); group irradiated at 10 J/cm(2) (G10); and group irradiated at 50 J/cm(2) (G50). Each group was divided into 3 different subgroups (n=7), and on days 7, 14 and 21 post-injury the rats were sacrificed. Seven days post-surgery, the CG showed destroyed zones and extensive myofibrillar degeneration. For both treated groups, the necrosis area was smaller compared to the CG. On day 14 post-injury, treated groups demonstrated better tissue organization, with newly formed muscle fibers compared to the CG. On the 21(st) day, the irradiated groups showed similar patterns of tissue repair, with improved muscle structure at the site of the injury, resembling uninjured muscle tissue organization. Regarding collagen deposition, the G10 showed an increase in collagen synthesis. In the last period evaluated, both treated groups showed statistically higher values in comparison with the CG. Furthermore, laser irradiation at 10 J/cm(2) produced a down-regulation of cyclooxygenase 2 (Cox-2) immunoexpression on day 7 post-injury. Moreover, Cox-2 immunoexpression was decreased in both treated groups on day 14. Laser therapy at both fluencies stimulated muscle repair through the formation of new muscle fiber, increase in collagen synthesis, and down-regulation of Cox-2 expression.