| Summary: | Probiotic bacteria are used for food biopreservation because their metabolic products might contribute to ensuring food microbiological safety and/or increase its shelf life without the addition of chemical preservatives. Moreover, biopreserved foods are excellent vehicles for the delivery of probiotic bacteria. The aim of the study was to investigate the potential of chocolate mousse food matrix for the delivery of the probiotic strain <i>Lactobacillus</i> <i>helveticus</i> 2/20 (<i>Lb. helveticus</i> 2/20) and to investigate its capacity to inhibit the growth of two foodborne pathogenic bacteria (<i>Staphylococcus</i> <i>aureus</i> and <i>Escherichia</i> <i>coli</i>). Therefore, the populations of free or encapsulated in calcium alginate <i>Lb. helveticus</i> 2/20 cells and/or of each pathogen (used to voluntarily contaminate each sample) were monitored both in complex nutrient medium (MRS broth) and in chocolate mousse under refrigeration conditions and at room temperature. <i>Lb. helveticus</i> 2/20 alone in free or encapsulated state effectively inhibited the growth of <i>Escherichia</i> <i>coli</i> ATCC 25922 and <i>Staphylococcus</i> <i>aureus</i> ATCC 25923 in chocolate mousse when stored at 20 ± 2 °C. Practically no viable unwanted bacteria were identified on the 7th day from the beginning of the process. High viable <i>Lb. helveticus</i> 2/20 cell populations were maintained during storage under refrigerated conditions (4 ± 2 °C) and at room temperature. Chocolate mousse is thus a promising food matrix to deliver probiotic <i>Lb. helveticus</i> 2/20 cells, which could also protect it from contamination by unwanted bacteria.
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