Características fisicoquímicas, sensoriales y microbiológicas de queso crema elaborado con adición de bacterias ácido lácticas como cultivo iniciador//Physicochemical, sensory, and microbiological characteristics of ‘queso crema’ cheese made with lactic acid bacteria as a starter culture

El objetivo del presente trabajo fue aislar bacterias acido lacticas de leche y queso crema del estado de Chiapas, Mexico y evaluar su efecto como cultivo iniciador en las caracteristicas fisicoquimicas (color, firmeza, consistencia, humedad, acidez titulable, proteina, grasa y cenizas), sensoriales (sabor, aroma, textura, cremosidad y acidez) y microbiologicas (coliformes totales, mohos y levaduras) del mismo queso elaborado a partir de leche pasteurizada. Mediante resiembra consecutiva en placas con agar MRS, se aislaron 101 cepas de diferentes morfologias a partir de muestras de leche y queso crema elaborado con leche no pasteurizada, de las cuales 26 fueron presuntivamente acido lacticas. Por su capacidad acidificante (descenso del pH) se seleccionaron siete cepas, con las cuales se formularon tres tratamientos (combinaciones de tres cepas, denominados T2-T4). El tratamiento que, despues del queso control (T1) sensorialmente fue el mas aceptado por los jueces, se reformulo en tres nuevas combinaciones de dos cepas (T5-T7). De estos tratamientos, el T5 (cepas E16 y E23) fue similar en color, aroma, sabor, textura y cremosidad al control (queso elaborado con leche sin pasteurizar). A pesar de que fueron diferentes en cuanto a la acidez, los jueces no lograron diferenciar (prueba cuantitativa) el queso T5 del control. ABSTRACT The aim of this work was to isolate lactic acid bacteria from milk and ‘queso crema’ cheese and evaluate their effect as starter on physicochemical (color, firmness, consistency, moisture, titratable acidity, protein, fat, and ash), sensory (flavor, aroma, texture, creaminess and sourness), and microbiological (total coliforms, molds and yeasts) characteristics of the same cheese made using pasteurized milk. By consecutive plating on MRS agar, 101 strains of different morphologies were isolated from samples of milk and cheese made with unpasteurized milk, of which 26 were presumptively lactic acid. Due to its acidifying capacity (measured as a decreased in pH), seven strains were selected, with which three treatments were formulated (combinations of three strains, called T2-T4). The treatment that, after the control cheese (T1) was the most accepted by the judge’s panel, was reformulated in three new combinations of two strains each (T5-T7). Of these treatments, T5 (containing strains E16 and E23) was similar in color, aroma, flavor, texture and creaminess to the control (cheese made with unpasteurized milk). Although the T5 cheese was different to control in acidity, the judges could not differentiate (quantitative test) between both samples.