CARACTERÍSTICAS DEL QUESO TEPEQUE DE LA TIERRA CALIENTE DE MICHOACÁN: UN QUESO PRODUCIDO EN UN SISTEMA SILVOPASTORIL INTENSIVO

El objetivo del presente estudio fue describir las características del Queso Tepeque de la Tierra Caliente del Estado de Michoacán en términos de su región de origen, proceso de manufactura, características fisicoquímicas y microbiológicas, y documentar los cambios atribuibles a la implementación de un sistema silvopastoril intensivo (SSPi) para la alimentación del ganado. La metodología consintió en visitar la zona de estudio para recolectar información sobre el territorio donde se produce el queso, se realizaron entrevistas semi- estructuradas a productores para conocer el sistema de producción de leche y el proceso de elaboración del queso. Se determinaron las características físicas (pH y densidad) y químicas (contenidos de proteína, grasa, lactosa, sólidos no grasos y agua adicionada) de la leche que se emplea en la elaboración del queso. En el queso se determinó su contenido de proteína, grasa, sal, humedad, cenizas y pH. Se determinaron las características sanitarias de ambos productos incluyendo conteo de microorganismos mesófilos aerobios, coliformes, hongos, levaduras y la presencia de Listeria spp y Staphylococcus aureus. El estudio se llevó a cabo en el año 2010, se dividió en dos períodos, época de lluvias y época de estiaje. Se estudiaron 15 productores, siete del SSPi y ocho del sistema tradicional de producción de leche. Se observó que el Queso Tepeque es un producto de excelente calidad desde el punto de vista de sus principales nutrientes, está elaborado con leche de buena calidad fisicoquímica, tiene una historia y tradición que supera los 300 años. El queso elaborado con leche de SSPi presenta características similares (P>0.05) e incluso superiores en el contenido de grasa (P0.05) atribuibles al SSPi en ninguno de los parámetros evaluados. Finalmente, la calidad sanitaria de la leche y el queso fue deficiente en ambos sistemas, aunque el proceso de maduración atenúa este problema, por lo que el consumo de queso madurado y añejado se recomienda en lugar del queso oreado

Physico-chemical, sensory and texture properties of an Aged Mexican Manchego-style cheese produced from hair sheep milk

Articulo publicadoThe objective of this study was to evaluate the physicochemical and texture changes of the Manchego-style cheese produced from hair sheep (Pelibuey) throughout 180 days of ripening, as well as consumer’s acceptance. Cheese pH was constant from 1 to 180 days of ripening. Moisture, water activity, fat, elasticity and hardness decreased from day 1 to day 180, while protein, trichloroacetic acid-soluble N and free amino acid increased. Cheese lightness decreased as ripening time increased, while elasticity and hardness decreased. Principal Component Analysis was useful in discriminating cheeses according to their physicochemical composition and that allowed cheeses to be classified in two groups according to their ripening time and this resulted in those with less than 60 days and those with more than 90 days of ripening. Compared with cheeses ripened at 1 and 90 days, aged cheeses at 180 days reduced scores for appearance, color, odor, taste, texture and overall acceptance. Overall, Manchego-style cheeses from hair sheep had the usual ripened-cheese physicochemical changes.The authors are grateful for the assistance of engineer Walter Lanz Villegas, who granted access to the facilities of the Centro de Integracion Ovina del Sureste (CIOS). We also thank D. Arcos-Alvarez, E. Bautista-Diaz, R. Espinosa-Mendoza and R. I. Narváez-Ballesteros for their technical assistance. The first author is grateful for the research grant provided by the National Council of Science and Technology of Mexico (CONACYT) for his postgraduate studies at the Universidad Juárez Autónoma de Tabasco, Mexico

Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements