Evaluation of the survival of Listeria monocytogenes and lactic acid bacteria in mango, custard apple and blackberry fruit juice concentrates from Costa Rica

In the last years, the consumption of natural products has increased. Fruit concentrates and derivates are part of these new products of high demand. Although these products present high acidity, they have been linked to the transmission of different pathogenic microorganisms. The aim of this study was to determine the potential survival of three different concentrations of Listeria monocytogenes inoculated into three different fruit juice concentrates of high demand in Costa Rica, including custard apple, black berry and mango, through its shelf life at refrigeration temperature. At the same time, lactic acid bacteria count was determined in order to describe the potential spoilage of these products. Blackberry concentrate did not allow the survival of the different inoculum of L. monocytogenes added as well as lactic acid bacteria. Custard apple concentrate allowed a slight survival of L. monocytogenes and lactic acid bacteria. Mango concentrates allowed, however, the survival of both L. monocytogenes and lactic acid bacteria during the storage period. Although juice concentrates have many intrinsic and extrinsic properties that represent a barrier for the survival and growth of microorganisms, L monocytogenes may overcome them, representing a risk for human health.