Profile of lactic acid bacteria (MALDI-TOF-MS) and physico-chemical and microbiological characteristics of the raw milk and fresh artisanal cheese from Serra Geral, Minas Gerais, Brazil.

Artisanal cheese from Serra Geral, Minas Gerais, Brazil, stands out for its cultural asset and socio-economic relevance. However, standards of identity and quality and the peculiar terroir associated with the edaphoclimatic conditions have not been established. Therefore, the production flow diagram and the physico-chemical and microbiological quality of the raw milk, pingo (natural starter culture), production benches, water and fresh cheese were investigated for the first time. In addition, lactic acid bacteria (LAB) from cheese and its production environment were identified by MALDI-TOF. For that, 12 cheese making facilities were selected. The raw milk and pingo showed adequate physico-chemical characteristics for cheesemaking; however, high microbial counts were found. In the water, total and thermotolerant coliforms were also identified. The fresh cheeses were classified as 'high moisture and fat' and 'soft mass'. Most physico-chemical parameters were satisfactory; however, there were high counts of total coliforms, Staphylococcus spp. and coagulase-positive staphylococci. There were high counts of LAB in the raw milk, pingo, bench surface and fresh cheese. A total of 84 microbial biotypes from MRS agar were isolated. Lactococcus lactis was the predominant LAB, followed by Lactococcus garvieae. Leuconostoc mesenteroides (benches), Leuconostoc pseudomesenteroides (fresh cheese), and Enterococcus faecium (pingo) were identified sporadically. These results indicate the risks to public health associated with the consumption of the fresh cheese, and measures to improve its safety are needed.

Fermentative characteristics and nutritional value of sugarcane silage added with two types of urea / Características fermentativas y valor nutricional del ensilaje de caña de azúcar con adición de dos tipos de urea / Características fermentativas e valor nutricional da silagem de cana-de-açúcar aditivada com dois tipos de ureia

Abstract Background: Dry matter (DM) loss is high in sugarcane silage due to its high content of soluble carbohydrates which favors yeast growth and ethanol production, thus reducing the nutritional value of the preserved forage. Objective: To determine the effect of adding two types of urea at two concentration levels to sugarcane silage on the nutritional value and fermentative characteristics of the silage. Methods: A completely randomized 2×2+1 factorial design was used, based on two types of urea (conventional and protected), two urea concentration (0.5 and 1.0% of the natural matter), and a control (sugarcane silage with no additives). Six replicates were used. The mixture was placed in PVC silos and opened after 60 days. Results: There was no difference in DM content or effluent losses by the addition of urea. In regards to neutral detergent fiber, acid detergent fiber, and lignin, decreased levels were observed compared to the control, regardless of urea type. Urea type and concentration had an effect on ammoniacal nitrogen content, with higher values for conventional urea, but not affecting the pH. The addition of urea to sugarcane silage reduced gas losses and raised the levels of crude protein, ether extract, and effective degradability. Conclusion: Adding protected or conventional urea at 1% of natural matter at the time of sugarcane ensiling reduces gas losses and improves nutritional composition of the silage.

Resumen Antecedentes: La caña de azúcar ensilada presenta una elevada pérdida de materia seca (MS) debido a su alto contenido de carbohidratos solubles que favorece el crecimiento de levaduras y la producción de etanol, reduciendo así el valor nutricional del ensilado. Objetivo: Determinar el efecto de dos tipos de urea en dos concentraciones sobre las características fermentativas y el valor nutricional del ensilaje de caña de azúcar. Métodos: Se utilizó un diseño completamente al azar, en esquema factorial 2x2+1, basado en dos tipos de urea (común o protegida), dos concentraciones de urea (0,5 y 1,0% de la materia natural) y un control (ensilaje de caña de azúcar sin aditivos). Se utilizaron seis réplicas de cada tratamiento. El material fue ensilado en silos de PVC, los que fueron abiertos después de 60 días. Resultados: No hubo diferencia en el contenido de MS o en las pérdidas por efluentes con la adición de urea. En relación a la fibra detergente neutra, fibra detergente ácida y lignina, se observó disminución de éstos con respecto al control, independientemente del tipo de urea. Se observó un efecto de la concentración y del tipo de urea para el contenido de nitrógeno amoniacal, con mayores valores para la urea común, pero sin efecto sobre el pH. La adición de urea en el ensilado de caña redujo las pérdidas por gases y elevó los niveles de proteína bruta, extracto etéreo y degradabilidad efectiva. Conclusión: La adición de urea común o protegida, al 1% de materia natural, al inicio del ensilaje de caña de azúcar reduce las pérdidas por gases y mejora la composición nutricional del ensilaje.

Resumo Antecedentes: A ensilagem de cana-de-açúcar sem aditivos apresenta elevada perda de matéria seca (MS) devido ao alto teor de carboidratos solúveis, favorecendo o crescimento de leveduras e produção de etanol, reduzindo assim o valor nutricional da forragem conservada. Objetivo: Determinar o efeito do tipo de ureia (comun ou protegida) e diferentes concentrações nas características fermentativas e valor nutritivo das silagens de cana-de-açúcar. Métodos: Utilizou-se um delineamento inteiramente casualizado em esquema fatorial 2 x 2 + 1, sendo dois tipos de ureia (comun ou protegida), e duas concentrações (0,5 e 1,0% com base na matéria natural) mais o controle (silagem exclusiva de cana-de-açúcar); com seis repetições. O material foi ensilado em silos de PVC e abertos após 60 dias. Resultados: Não houve diferença no teor de MS e nas perdas por efluentes com adição da ureia. Em relação à fibra em detergente neutro, fibra em detergente ácido e lignina observou-se diminuição destes em relação ao controle, independente do tipo de ureia. Observou-se efeito das concentrações e do tipo de ureia para o teor de nitrogênio amoniacal, com maiores valores para a ureia comum, porém sem efeito no pH. A adição de ureia na ensilagem de cana reduziram as perdas por gases e elevaram os teores de proteína bruta, extrato etéreo e degradabilidade efetiva. Conclusão: O uso de 1% de ureia, independente do tipo, promove um incremento no valor nutricional da silagem de cana-de-açúcar e reduz as perdas por gases.