Resumen El objetivo fue evaluar ensilado de Tithonia tubiformis con diferentes aditivos para determinar composición química, parámetros de fermentación ruminal y de producción de gas in vitro. Se evaluaron dos etapas fenológicas (floración y reproductiva) y tres tratamientos de aditivos; control (CTR), melaza (MLZ) y bacterias ácido lácticas (BAL), mediante un diseño experimental factorial 3x2. Las variables evaluadas fueron materia seca (MS), materia orgánica (MO), proteína cruda (PC), fibra detergente neutro (FDN), fibra detergente acido (FDA), energía metabolizable estimada (eEM), digestibilidad in vitro de la MS (DIVMS), MO (DIVMO) y de la FDN (DIVFDN) y producción de gas in vitro. Se presentaron diferencias (P < 0.05) en las variables de composición química, digestibilidad in vitro, eEM y parámetros de cinética de fermentación entre tratamientos a excepción de FDA, DIVFDN, C1, B, C2 y lag, para etapas fenológicas se presentaron diferencias (P < 0.05) en todas las variables a excepción de FDN, FDA, A y C1.

Abstract The objective was to evaluate Tithonia tubiformis silage with different additives to determine its chemical composition, ruminal fer mentation parameters and in vitro gas production, two phenological stages (flowering and reproductive) and three additive treatments for the silages were evaluated; control (CTR), molasses (MLZ) and lactic acid bacteria (BAL), through an analysis of variance with a 3x2 factorial experimental design. The variables evaluated were dry matter (DM), organic matter (OM), crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF), estimated metabolizable energy (eEM), in vitro digestibility of DM (IVDDM), MO (IVDOM) and NDF (IVDNDF), as well as in vitro gas production. Differences (P < 0.05) were found in the chemical composition, in vitro digestibility, eEM and parameters of fermentation kinetics variables between treatments, except for ADF, IVNDF, C1, B, C2 and lag, regarding phenological stages there were differences (P < 0.05) in all variables except for NDF, ADF, A and C1.

Abstract Traditional Zacazonapan cheeses have unique organoleptic characteristics and are characterized by being linked to the territory of origin. In the maturation process, there are many interactive variables that are responsible for physical, chemical, biological and structural changes. In order to evaluate the bacteriological evolution of artisanal cheeses during their maturation under non-controlled conditions in two production periods, samples of raw milk and cheese were collected at 0, 30, 60, 120 and 150 d of maturation. The presence of molds and yeasts (MaY), mesophilic aerobic bacteria (MAB), Staphylococcus spp. (Staph), total coliforms (TC), fecal coliforms (FC), Salmonella spp. (Salm) and Listeria spp. (List) was determined. The average microbial load was 9.68, 9.38, 8.55 and 8.10 log10 CFU/g of cheese for MaY, MAB, Staph and TC respectively, as well as 2.68 log10 MPN/g of cheese for FC. Salm was not detected but List was. The microbiological evolution of Zacazonapan matured cheese had counts that exceed the maximum levels of the Official Mexican Standard 243 SSA1 2010.

Resumen Los quesos tradicionales Zacazonapan tienen características organolépticas únicas y se caracterizan por estar vinculados al territorio de origen. En el proceso de maduración se tienen numerosas variables interactivas que son responsables de los cambios físicos, químicos, biológicos y estructurales. Con el objetivo de evaluar la evolución bacteriológica de quesos artesanales durante su maduración bajo condiciones no controladas en dos épocas de producción, se colectaron muestras de leche cruda y de queso a los 0, 30, 60, 120 y 150 días de maduración. Se determinó la presencia de mohos y levaduras (MyL), bacterias mesófilas aerobias (BMA), Staphylococcus spp. (Staph), coliformes totales (CT), coliformes fecales (CF), Salmonella spp. (Salm) y Listeria spp. (List). La carga microbiana promedio fue 9.68, 9.38, 8.55 y 8.10 log10 UFC/g de queso para MyH, BMA, Staph y CT respectivamente, así como 2.68 log10 NMP/g de queso para CF. No se detectó Salm pero si List. La evolución microbiológica del queso madurado Zacazonapan presentó conteos que superan los niveles máximos de la Norma Oficial Mexicana 243 SSA1 2010.

Abstract: Objective: To determine the prevalence and the degree of contamination by molds and yeasts (M&Y), aerobic mesophilic bacteria (AMB), total coliforms (TC) and Salmonella spp. (S). These microorganisms were considered indicators of quality and hygiene in the manufacturing environment of Zacazonapan cheese. Materials and methods: Samples from five cheese dairies at Zacazonapan municipality were collected. The samples were collected directly from hands, water, milk, curd, cheese and surface of utensils for cheese making. Results: All surfaces sampled were contaminated, there was an evident lack of hygiene in the cheese making process, the microorganisms count during cheese manufacturing were: for milk; 6.8, 6.7 and 4.5 log10 CFU/ml for M&Y, AMB and TC, respectively. For cheese, the presence of S was detected and presented the following counting: 9.16, 9.23 and 9.18 log10 CFU/g to M&Y, AMB and TC. Conclusions: The lack of hygiene in dairies and implements for cheese manufacturing represents a risk for human health.

Resumen: Objetivo: Determinar la prevalencia y el grado de contaminación por mohos y levaduras (M&L), bacterias mesófilas aerobias (BMA), coliformes totales (CT) y Salmonella spp. (S) como indicadores de calidad e higiene en el entorno de fabricación del queso de Zacazonapan. Material y métodos: En cinco queserías se obtuvieron muestras de agua, leche, cuajo y queso, y de superficie de las manos y de los utensilios que están en contacto con el queso. Resultados: Todas las superficies presentaron contaminación; por lo tanto, se observa falta de higiene al elaborar el queso. Los conteos durante la elaboración de queso fueron, para leche, de 6.8, 6.7 y 4.5 log10 UFC/ml para M&L, BMA y CT, respectivamente. En queso, se detectó la presencia de S y cuentas de 9.16, 9.23 y 9.18 log10 UFC/g para M&L, BMA y CT. Conclusiones: La poca higiene en queserías y utensilios al elaborar el queso representa un riesgo para la salud humana.

Abstract: Objective: To determine the prevalence and the degree of contamination by molds and yeasts (M&Y), aerobic mesophilic bacteria (AMB), total coliforms (TC) and Salmonella spp. (S). These microorganisms were considered indicators of quality and hygiene in the manufacturing environment of Zacazonapan cheese. Materials and methods: Samples from five cheese dairies at Zacazonapan municipality were collected. The samples were collected directly from hands, water, milk, curd, cheese and surface of utensils for cheese making. Results: All surfaces sampled were contaminated, there was an evident lack of hygiene in the cheese making process, the microorganisms count during cheese manufacturing were: for milk; 6.8, 6.7 and 4.5 log10 CFU/ml for M&Y, AMB and TC, respectively. For cheese, the presence of S was detected and presented the following counting: 9.16, 9.23 and 9.18 log10 CFU/g to M&Y, AMB and TC. Conclusions: The lack of hygiene in dairies and implements for cheese manufacturing represents a risk for human health.

Resumen: Objetivo: Determinar la prevalencia y el grado de contaminación por mohos y levaduras (M&L), bacterias mesófilas aerobias (BMA), coliformes totales (CT) y Salmonella spp. (S) como indicadores de calidad e higiene en el entorno de fabricación del queso de Zacazonapan. Material y métodos: En cinco queserías se obtuvieron muestras de agua, leche, cuajo y queso, y de superficie de las manos y de los utensilios que están en contacto con el queso. Resultados: Todas las superficies presentaron contaminación; por lo tanto, se observa falta de higiene al elaborar el queso. Los conteos durante la elaboración de queso fueron, para leche, de 6.8, 6.7 y 4.5 log10 UFC/ml para M&L, BMA y CT, respectivamente. En queso, se detectó la presencia de S y cuentas de 9.16, 9.23 y 9.18 log10 UFC/g para M&L, BMA y CT. Conclusiones: La poca higiene en queserías y utensilios al elaborar el queso representa un riesgo para la salud humana.