Diagnóstico de la calidad sanitaria en las queserías artesanales del municipio de Zacazonapan, Estado de México / Diagnostic of health quality in artisanal cheese dairies of Zacazonapan municipality, State of Mexico

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.

Nutritional value of forage species from the Central Highlands Region of Mexico at different stages of maturity / Valor nutricional de espécies forrageiras nativas da Região Central Montanhosa do México em diferentes estádios de maturidade

This paper has two objectives, the first is to determine the chemical composition, gas production parameters and the gas release kinetics, at different stages of maturity, of three grasses and a legume commonly found in long established pastures in Mexico central highland plateau. The second is to combine the gas release kinetics analysis and the GP fitted to a mathematical model in order to improve the biological understanding of the fermentation kinetics obtained from the GP technique. Representative samples of Pennisetum clandestinum (kikuyu grass), Sporobolus indicus (mouse tail), Eleocharis dombeyana (reed), Trifolium amabile (Aztec clover) plus a composite sample were collected in the growing season (July, September and November 2003) and analysed using an in vitro gas production (GP) technique. The accumulated GP was fitted to the model described in PALMER et al. (2005). Significant differences (P<0.001) were observed among species and periods for chemical composition, organic matter and neutral detergent fibre digestibility. Significant differences (P<0.05) were observed regarding fermentation parameters and gas release kinetic, with T. amabile and P. clandestinum being the species with the highest fermentability, whereas S. indicus and E. dombeyana were poorly fermented. P. clandestinum and T. amabile showed higher nutritive value than S. indicus and E. dombeyana. Composite samples were influenced by the chemical and fermentation characteristics of all species. It was concluded that the use of gas release kinetics analysis was useful for differentiating the fermentation kinetic of the soluble and insoluble fraction in the grasses and legume. Therefore by performing both approaches, the gas release kinetics analysis and the GP fitted to a mathematical model, gave a better description of the fermentation kinetic of grasses and the legume was achieved when only one approach had been used.

O uso da análise de cinética de produção de gases, em conjunto com a análise de prova de curva e as propriedades químicas da forragem permitem uma melhor descrição das características nutritivas das forragens. Objetivou-se estudar a composição nutritiva e características de fermentação de ruminal de três gramíneas, uma leguminosa e uma mistura composta de pastagens do Planalto Montanhoso Central do México. As amostras representativas de Pennisetum clandestinum (kikuyu grama), Sporobolus indicus (rabo de rato), Eleocharis dombeyana (cana), Trifolium amabile (trevo asteca) mais uma amostra composta foram coletadas durante os meses de Julho, Setembro e Novembro de 2003. Foi utilizada a técnica de produção de gás in vitro (GP). Os perfis de GP foram ajustados ao modelo descrito por PALMER et al. (2005). As diferenças (P<0.001) foram observadas entre espécies e períodos quanto à composição química, matéria orgânica e digestibilidade da fibra em detergente neutro. As diferenças (P<0.05) dos parâmetros de fermentação e cinética de produção de gases mostraram T. amabile e P. clandestinum com fermentação mais intensa, ao passo que S. indicus e E. dombeyana tiveram fermentação limitada. Concluiu-se que a combinação da análise de cinética de produção de gases e o perfil de GP ajustado ao modelo matemático ajudou a descrever as características nutritivas das gramíneas, da leguminosa e da amostra composta de forma mais acurada do que quando um dos métodos foi utilizado de forma isolada.