Multilocus typing sequences in Lactobacillus casei isolates from pineapple peels silages

Introducción. Lactobacillus casei se caracteriza por adaptarse al medio durante el proceso fermentativo. Objetivo. Caracterizar con tipificación de secuencias multilocus (MTLS), aislamientos de L. casei presentes en ensilados de cáscara de piña con niveles crecientes de urea. Materiales y métodos. Durante 2017 y con un diseño irrestricto al azar se prepararon veinte silos (2 kg). Cada cinco bolsas, se adicionaron 0, 0,5, 1 y 1,5 % de urea (p/p en base fresca). Después de treinta días, se tomó una muestra de cada repetición para realizar análisis bromatológicos. Se analizó materia seca (MS), proteína cruda (PC), carbohidratos no fibrosos, fibra en detergente ácido (FDA), fibra en detergente neutro (FDN), digestibilidad in vitro de la materia seca (DIVMS), hemicelulosa, extracto etéreo (EE), cenizas, nitrógeno amoniacal y pH. Se determinó el recuento de bacterias ácido-lácticas (BAL) para cada uno de los tratamientos. La identificación de las BAL se realizó con la secuencia del ARNr 16S. Los aislamientos de L. casei fueron analizados con MTLS. Resultados. Los cuatro tratamientos evaluados no presentaron diferencias significativas en la MS (12,10 a 12,86%), FDA (31,44 a 32,18 %), FDN (58,46 a 58,56 %), hemicelulosa (26,36 a 27,02 %), EE (2,45 a 2,96 %), cenizas (4,96 a 5,12%), nitrógeno amoniacal (0,45 a 0,49 %) y pH (3,36 a 3,48). No así, en PC (6,94 a 9,12 %) y DIVMS (82,84 a 84,72 %). La adición de urea se asoció a cambios en las poblaciones de BAL (6,56 a 6,90 UFC). Siete aislamientos de L. casei se identificaron y tipificaron con cinco genes distintos. Se encontraron entre dos (polA) y cinco (nrdD, pgm, mutL) alelos; esto permitió identificar un total de seis secuencias tipo (ST) distintas en los aislados de Costa Rica. Conclusión. Los aislamientos de L. casei se encontraron emparentados a bacterias del tracto gastrointestinal en humanos.Introduction. Lactobacillus casei is characterized by adapting to the environment during the fermentation process. Objective. To characterize with multilocus typing sequences (MTLS) isolates of L. casei present in pineapple peel silage with increasing levels of urea. Materials and methods. During 2017 and using an unrestricted random design, twenty silos (2 kg) were prepared. Every five bags, 0, 0.5, 1 and 1.5 % urea (w/w on fresh basis) were added. After thirty days, a sample was taken from each repetition for bromatological analysis. Dry matter (DM), crude protein (PC), non-fibrous carbohydrates, fiber in acid detergent (ADF), fiber in neutral detergent (NDF), in vitro digestibility of dry matter (IVDDM), hemicellulose, ethereal extract (EE), ashes, ammonia nitrogen, and pH. The Lactic Acid Bacteria (LAB) count was determined for each one of the treatments. Identification of LABs was carried out using the 16S rRNA sequence. The isolates of L. casei were analyzed using MTLS. Results. The four evaluated treatments did not present significant differences in DM (12.10 to 12.86 %), ADF (31.44 to 32.18 %), NDF (58.46 to 58.56 %), hemicellulose (26.36 to 27.02 %), EE (2.45 to 2.96 %), ash (4.96 to 5.12 %), ammonia nitrogen (0.45 to 0.49 %) and pH (3.36 at 3.48). Not so, in CP (6.94 to 9.12 %), and IVDDMS (82.84 to 84.72 %). The addition of urea was associated with changes in the BAL populations (6.56 to 6.90 CFU). Seven isolates of L. casei were identified and typed with five different genes. Between two (polA) and five (nrdD, pgm, mutL) alleles were found. This allowed the identification of a total of six different type sequences (ST) in the Costa Rican isolates. Conclusion. The L. casei isolates were found to be related to bacteria from the gastrointestinal tract in humans.Universidad de Costa Rica/[801-B5-505]/UCR/Costa RicaUCR::Vicerrectoría de Docencia::Ciencias Agroalimentarias::Facultad de Ciencias Agroalimentarias::Escuela de ZootecniaUCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Agroalimentarias::Centro de Investigación en Nutrición Animal (CINA)UCR::Vicerrectoría de Docencia::Salud::Facultad de MicrobiologíaUCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias de la Salud::Centro de Investigación en Enfermedades Tropicales (CIET)UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Agroalimentarias::Centro Nacional de Ciencia y Tecnología de Alimentos (CITA)UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Agroalimentarias::Centro de Investigaciones Agronómicas (CIA)UCR::Vicerrectoría de Docencia::Ciencias Agroalimentarias::Facultad de Ciencias Agroalimentarias::Escuela de Tecnología de AlimentosUCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Básicas::Centro de Investigación en Biología Celular y Molecular (CIBCM

Multi-Product Lactic Acid Bacteria Fermentations: A Review

Industrial biotechnology is a continuously expanding field focused on the application of microorganisms to produce chemicals using renewable sources as substrates. Currently, an increasing interest in new versatile processes, able to utilize a variety of substrates to obtain diverse products, can be observed. A robust microbial strain is critical in the creation of such processes. Lactic acid bacteria (LAB) are used to produce a wide variety of chemicals with high commercial interest. Lactic acid (LA) is the most predominant industrial product obtained from LAB fermentations, and its production is forecasted to rise as the result of the increasing demand of polylactic acid. Hence, the creation of new ways to revalorize LA production processes is of high interest and could further enhance its economic value. Therefore, this review explores some co-products of LA fermentations, derived from LAB, with special focus on bacteriocins, lipoteichoic acid, and probiotics. Finally, a multi-product process involving LA and the other compounds of interest is proposed

Fruit-based fermented beverages : contamination sources and emerging technologies applied to assure their safety

The food and beverage market has become broader due to globalization and consumer claims. Under the umbrella of consumer demands, legislation, nutritional status, and sustainability, the importance of food and beverage safety must be decisive. A significant sector of food production is related to ensuring fruit and vegetable conservation and utilization through fermentation. In this respect, in this review, we critically analyzed the scientific literature regarding the presence of chemical, microbiological and physical hazards in fruit-based fermented beverages. Furthermore, the potential formation of toxic compounds during processing is also discussed. In managing the risks, biological, physical, and chemical techniques can reduce or eliminate any contaminant from fruitbased fermented beverages. Some of these techniques belong to the technological flow of obtaining the beverages (i.e., mycotoxins bound by microorganisms used in fermentation) or are explicitly applied for a specific risk reduction (i.e., mycotoxin oxidation by ozone). Providing manufacturers with information on potential hazards that could jeopardize the safety of fermented fruit-based drinks and strategies to lower or eliminate these hazards is of paramount importance.info:eu-repo/semantics/publishedVersio

Safety Assurance And Quality Enhancement Of Juices By The Application Of Traditional Thermal Treatments And Nonthermal Processes

Outbreaks associated with the consumption of contaminated juices have stressed the relevance of introducing a microbial killing step during processing of these products. Nonetheless, some unanswered questions regarding the application of pasteurization and nonthermal technologies, such as UV light, to ensure the safety of beverages with a pH below 4.6 have been identified. Hence, this research project aimed to address some of these existing gaps of information and therefore assist the food industry, regulatory agencies and process authorities with the establishment of critical limits for the safe thermal or UV processing of low-pH drinks. The thermal tolerance of E. coli O157:H7 in apple-carrot juice blends, using different acids and at variable pH values was determined. Then, the effect of different methodologies of acid adaptation and acid shock on the thermal tolerance and survival of three Shiga toxin-producing E. coli strains was assessed. Furthermore, the impact of the concentration of insoluble solids and the darkening of juice after apple pressing, on the efficiency of UV treatments were studied and, the influence of the addition of selected additives and preservatives on the efficiency of the UV treatment of apple juice and the impact of UV radiation over those compounds was additionally evaluated. This dissertation will provide the juice and beverage industries with relevant information to meet some of the science-based rules stated in current and new regulations, including the Food Safety Modernization Act

Detección de gluten en alimentos etiquetados como libres de gluten disponibles en el mercado costarricense

La presencia de gluten en alimentos etiquetados como libres de gluten (LG) representa una preocupación para la salud de pacientes celíacos, y personas intolerantes y sensibles a este conjunto de proteínas. Sin embargo, esto no ha sido estudiado aún en países centroamericanos. Por tanto, se investigó la presencia de gluten en alimentos etiquetados LG, manufacturados en Costa Rica y disponibles en el mercado entre los años 2016 y 2017 para determinar así el cumplimiento de las regulaciones nacionales e internacionales. Se ha estipulado que dichos alimentos deben contener <20 ppm de gluten. Un total de 173 productos fueron analizados por inmunoensayo (tres muestras por producto; cada una de un lote diferente) utilizando el kit ELISA RIDASCREEN®. 60 marcas de productos, de 32 compañías diferentes, fueron evaluadas identificando 15 categorías de alimentos LG: productos horneados, premezclas y harinas, snacks, granos y cereales, salsas, productos cárnicos, productos de origen marino, bebidas, productos lácteos, pastas, chocolates, aceites, tortillas y arepas, jaleas y mermeladas y otros. Una muestra de uno de los productos analizados presentó >20 ppm de gluten. No obstante, al menos una muestra de 49 productos diferentes (28% de los productos analizados) presentó una concentración cuantificable de gluten (>5 ppm) evidenciando una alta variabilidad en los resultados. Esta investigación evidencia el fuerte compromiso de la industria alimentaria costarricense para cumplir la norma que regula la producción de alimentos LG durante el período de estudio, aunque se alerta acerca de la necesidad de implementar mejoras en los sistemas de producción y vigilancia de estos alimentos. The presence of gluten in gluten free (GF) labelled foods represents a serious health concern to celiac patients and persons intolerant or sensitive to this set of proteins. However, this has not yet been studied in Central American countries. Therefore, the presence of gluten in foods labeled LG, manufactured in Costa Rica and available in the market, between 2016 and 2017, was investigated to determine compliance with national and international regulations. It has been stipulated that such foods must contain <20 ppm of gluten. A total of 173 products were analyzed by immunoassay (three samples per product; each from an independent batch), using the ELISA RIDASCREEN® kit. 60 product brands, from 32 different companies, were evaluated and 15 GF food categories were identified: baked products, baking mixes and flours, snacks, grains and cereals, sauces, meat products, seafood, beverages, dairy products, pasta, chocolates, oils, tortillas and arepas, jams and jellies, and others. Only one sample from one of the tested products presented >20 ppm of gluten. However, at least one sample of 49 different products (28% of products tested) presented a quantifiable concentration of gluten (>5 ppm), showing a high variability of results. This research evidences the strong commitment of the Costa Rican food industry to comply with the norm that regulates the production of LG foods during the study period, even though it warns about the need to implement improvements in the production and surveillance systems of these foods

Gluten detection in foods labeled as gluten-free available in the Costa Rican market

La presencia de gluten en alimentos etiquetados como libres de gluten (LG) representa una preocupación para la salud de pacientes celíacos, y personas intolerantes y sensibles a este conjunto de proteínas. Sin embargo, esto no ha sido estudiado aún en países centroamericanos. Por tanto, se investigó la presencia de gluten en alimentos etiquetados LG, manufacturados en Costa Rica y disponibles en el mercado entre los años 2016 y 2017 para determinar así el cumplimiento de las regulaciones nacionales e internacionales. Se ha estipulado que dichos alimentos deben contener 20 ppm de gluten. No obstante, al menos una muestra de 49 productos diferentes (28% de los productos analizados) presentó una concentración cuantificable de gluten (>5 ppm) evidenciando una alta variabilidad en los resultados. Esta investigación evidencia el fuerte compromiso de la industria alimentaria costarricense para cumplir la norma que regula la producción de alimentos LG durante el período de estudio, aunque se alerta acerca de la necesidad de implementar mejoras en los sistemas de producción y vigilancia de estos alimentos.The presence of gluten in gluten free (GF) labelled foods represents a serious health concern to celiac patients and persons intolerant or sensitive to this set of proteins. However, this has not yet been studied in Central American countries. Therefore, the presence of gluten in foods labeled LG, manufactured in Costa Rica and available in the market, between 2016 and 2017, was investigated to determine compliance with national and international regulations. It has been stipulated that such foods must contain 20 ppm of gluten. However, at least one sample of 49 different products (28% of products tested) presented a quantifiable concentration of gluten (>5 ppm), showing a high variability of results. This research evidences the strong commitment of the Costa Rican food industry to comply with the norm that regulates the production of LG foods during the study period, even though it warns about the need to implement improvements in the production and surveillance systems of these foods.Universidad de Costa Rica/[735-B5-258]/UCR/Costa RicaUCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Agroalimentarias::Centro Nacional de Ciencia y Tecnología de Alimentos (CITA)UCR::Vicerrectoría de Docencia::Ciencias Agroalimentarias::Facultad de Ciencias Agroalimentarias::Escuela de Tecnología de Alimento

Microbial safety and quality evaluation of UV-Treated, cold-pressed colored and turbid juices and beverages

The growing demand for fruit and vegetable juice blends, with improved nutritional and sensory attributes, has prompted the industrial adoption of nonthermal processing technologies, including UV light. Limited studies have explored conditions to overcome the well-known limitations of UV when treating liquid foods with a high content of particles that absorb or scatter UV light. This study addressed the effectiveness of the application of UV light, using a commercial processing unit, to inactivate pathogenic Escherichia coli O157:H7, Salmonella enterica (hereafter Salmonella), and Listeria monocytogenes, as well as spoilage microorganisms, in colored and turbid juices and beverages. The inactivation of cocktails of five strains (or serotypes) of E. coli O157:H7, Salmonella, and L. monocytogenes isolated from fruit- and vegetable-derived products linked to outbreaks was determined in seven colored and turbid cold-pressed juices and beverages. Juices and beverages were UV treated at a constant flow rate of 150 L/h through multiple consecutive passes. The inactivation of aerobic mesophilic bacteria, molds and yeasts, and lactic acid bacteria was also assessed at the cumulative dose that guaranteed a 5-log reduction of the most UV-tolerant pathogen for each product. A 5-log reduction of the three pathogens was achieved in all juices and beverages at a maximum cumulative UV dose of 12.0 ± 0.6 mJ/cm2. The dose required to ensure the targeted reduction varied depending on the tested product and the inoculated pathogen. The reduction of aerobic mesophiles, molds and yeasts, and lactic acid bacteria varied from 0.5 to 3.6, from 0.2 to 2.0, and from 0.5 to 3.6 log CFU/mL, respectively. Thus, the proposed treatment represents a suitable processing alternative to ensure the safety and extend the shelf life of colored and turbid cold-pressed juices and beverages.UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Agroalimentarias::Centro Nacional de Ciencia y Tecnología de Alimentos (CITA

Reducción de sodio en salsa de tomate y mayonesa mediante la aplicación de un enfoque de umbral sensorial

El consumo excesivo de sodio es causa importante de enfermedades no transmisibles incluyendo hipertensión. En esta investigación se evaluó una metodología sensorial para reducir el contenido de sodio en salsas de tomate y mayonesas, productos altamente consumidos en Costa Rica. Se caracterizaron, por triplicado, 16 salsas y 7 mayonesas comerciales para determinar los ingredientes más comunes y sus características físicoquímicas. Se comparó el contenido de sodio reportado en la etiqueta contra el valor determinado experimentalmente. Se formularon prototipos de ambos productos y se determinó el umbral de diferencia apenas perceptible (DAP) para el gusto salado utilizando el método de estímulo constante con 40 panelistas no entrenados (d'= 1, significancia de 0,05 y potencia de prueba de 0,95). Se contruyeron las curvas psicofísicas con concentraciones de sal entre 0,67% y 2,5% para salsa de tomate y 0,13% y 4,16% para mayonesa; obteniéndose DAPs de 0,51% y 0,26% respectivamente; equivalentes a 28,3% y 14,4% menos de sal en cada producto. Para la validación del umbral, se aplicó una prueba de discriminación 2-AFC con 40 panelistas comparando la formulación regular con la reducida en sodio. Los panelistas no detectaron diferencias significativas entre mayonesas (P>0,05) pero sí entre salsas (P<0,05), por lo que se aplicó una prueba de agrado con 112 consumidores y se determinó que la salsa reducida en sodio resultó de mayor o igual agrado que la contraparte. Estos resultados guiarían a la industria alimentaria regional hacia el mejoramiento del perfil nutricional de estos productos.The excessive consumption of sodium is an important cause of noncommunicable diseases including hypertension. This research aimed, using a sensorial methodology, to reduce sodium content in tomato sauces and mayonnaise, highly consumed products in Costa Rica. A total of 16 commercial sauces and 7 mayonnaises were characterized to determine their most common ingredients and physicochemical properties. The sodium content reported in the labed was compared against values obtained experimentally. Prototypes for both products were developed and the threshold for the just noticiable difference (JND) for salty flavor was determined using the constant stimulus method with 40 panelists (d'= 1, 0.05 significance and a test power of 0,95). Psychophysical curves were built with salt concentrations between 0.67% and 2.5% for tomato sauce and 0.13% and 4.16% for mayonnaise; obtaining JNDs of 0.51% and 0.26% respectively; equivalent to 28.3% and 14.4% less salt in tomato and mayonnaise. To validate the threshold, a discriminatory 2-AFC test with 40 panelists was performed to compare the regular formulations against those reduced in sodium. Panelists did not detect significant differences among mayonnaises (P>0.05) but they did found differences between sauces (P<0.05). Thus, for tomato sauce a consumer liking test with 112 consumers was performed and it was found that sodium reduced tomato sauce was equally or more liked than its counterpart. These results guide the regional food industry towards the improval of the nutritional profile of both products

Lactic Acid Bacteria (LAB) Applications in the Food Industry: Probiotic Foods-A Mini Review

Lactic Acid Bacteria (LAB) is a diverse group of cocci and rods characterized by the production of Lactic Acid (LA). Some LAB, with probiotic traits, have been extensively used since ancient times on food production. Advances in science have given the opportunity to understand the organization of LAB genomes considering their habitats and interactions with other species. Nowadays, it is possible to carry out in vitro and in vivo tests to search for different LAB profiles and therefore applications, and to learn about the benefits they can offer to consumers. Some advantages that have been associated with their consumption is having a healthy intestinal microbiota, as well as the reduction of some digestive disorders. It is known that LAB can produce compounds such as LA, acetic acid, and other desirable by-products such as bacteriocins. These compounds are associated with the inhibition including of some pathogenic microorganisms among other properties.UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Agroalimentarias::Centro Nacional de Ciencia y Tecnología de Alimentos (CITA)UCR::Vicerrectoría de Docencia::Ciencias Agroalimentarias::Facultad de Ciencias Agroalimentarias::Escuela de Tecnología de Alimento