Evaluació n de la nisina como sustancia inactivadora de Bacillus licheniformis en el extracto lí quido de café

Abstract

Objetive: To evaluate the effect of nisin on the inactivation of Bacillus licheniformis to coffee liquid extract. Materials and methods: The action of nisin on Bacillus licheniformis into liquid coffee extracts was evaluated by varying its concentration, incubation time, concentration of soluble solids (oBrix) and bacterial contaminant concentration. Results: The results indicated that the concentration of nisin to achieve the inhibitory effect without affecting the physicochemical and sensory properties of the product is 500 IU/ml corresponding to 12.5 mg/L. Additionally, High levels of nisin 1000 IU/ml can act successfully in bacterial populations lower than 5×104 CFU/ml over a period of 48 hours. Furthermore, the concentration of soluble solids did not show a statistically significant effect for values from 15 to 45 oBrix. Conclusions: From this study it can be concluded that nisin may be used as a preservative in liquid coffee extract without sensorially affecting the product, taking into account the bacterial contaminant concentration and incubation time.