A study was conducted in 2006 to determine the prevalence of Salmonella on three cantaloupe farms in Matamoros, Coahuila, Mexico, and on one farm that cultivates chile peppers var. Bell in Culiacán, Sinaloa, Mexico. Samples from cantaloupe farms consisted of cantaloupe rinses, irrigation water, water from furrows in the field, and workers' hands. Samples from the chile pepper farm consisted of rinses of chile peppers obtained at the field, pepper rinses obtained at the packing house, and irrigation water from the field. A total of 55 samples were obtained from both production systems. Twelve and 10 samples from the cantaloupe and chile pepper production systems, respectively, tested positive for Salmonella according to a traditional culture method. The difference between the proportion of Salmonella-positive samples from the cantaloupe production system (12 of 28 = 0.43) and the chile pepper production system (10 of 27 = 0.37) was not statistically significant (P > 0.05). A PCR-restriction fragment length polymorphism (RFLP) method based on the fliC gene was used to determine the serotype of the isolates. Salmonella Typhimurium was the only serotype found associated with the cantaloupe production system, whereas both Salmonella Typhimurium and Enteritidis serotypes were found associated with the chile pepper production system. Results showed that 91% (20 of 22) and 9% (2 of 22) of the isolates from both agricultural systems matched with the Salmonella Typhimurium and Salmonella Enteritidis reference strain restriction profiles, respectively. This study demonstrates the utility of the PCR-RFLP technique for determining the serotypes of Salmonella isolates obtained from cantaloupe and chile pepper production systems.

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Introduction. The State of Nuevo Leon is considered the depositary of a wide genetic diversity of creole avocados (Persea americana var drimyfolia). Objective. The aim of this work was to determine the variability of the total oil content and the fatty acids profile in creole avocados from Nuevo Leon, Mexico. Materials and methods. During the spring and summer of 2016, 36 varieties of creole avocados were collected in the northern and southern region of the State of Nuevo Leon, Mexico for chemical characterization. The commercial variety “Hass” was included as a control. To determine the variability that exists in the content of total oils and fatty acids in the collected materials, analyzes of the main components and conglomerates were carried out. Results. Six fatty acids were detected in the total oil of the creole avocados: palmitic, stearic, oleic, palmitoleic, linoleic and linolenic. The outstanding varieties were “Platano temprano”, “Platano delgado”, “Huevo de toro”, “Cuerno”, “Pato”, and “Especial”, which presented an average of 17.28, 24.93 and 66.29 % more in the content of oleic, linoleic and linolenic acids respectively, and an average of 28.12 % less stearic acid compared to the commercial variety “Hass”. According to the analysis of main components, materials with high oleic acid content usually have low palmitic and palmitoleic acid contents. The dendrogram presented six groups within the evaluated materials, most of the outstanding materials are located in groups one and four. Conclusion. High variability in the content of total oils and fatty acids was determined in creole avocados from Nuevo Leon. Therefore, they are considered promising for their incorporation into genetic improvement programs.

Objetivo. Evaluar el efecto del horario de complementación con un alimento integral sobre la producción y composición química de la leche de cabras lactantes en condiciones de pastoreo en el norte de México. Materiales y métodos. Doce cabras Saanen adultas se asignaron en forma equitativa y aleatoria a tres tratamientos: testigo, complementación Mañana y complementación Tarde. Se midió consumo de materia seca (MS), peso vivo (PV), condición corporal (CC), producción de leche (PL), composición química y rendimiento de los componentes de la leche (proteína, lactosa y grasa). Resultados. El consumo mayor de MS total se obtuvo en las cabras complementadas por la tarde (p=0.02), y también fueron las que produjeron mayor cantidad de leche (p<0.0001). Las concentraciones de proteína (p=0.07) y lactosa (p=0.10) en leche no se modificaron por efecto de tratamientos. El contenido de grasa en leche de las cabras del grupo testigo fue mayor (p<0.05) que en los tratamientos con complementación. Conclusiones. La complementación por la tarde mejoró la respuesta productiva de cabras lactantes en pastoreo durante la época seca en el norte de México.