Bioprotection of ready-to-eat probiotic artichokes processed with Lactobacillus paracasei LMGP22043 against foodborne pathogens

The survival of 3 pathogens Listeria monocytogenes ATCC19115, Salmonella enterica subsp. enterica ATCC13311, and Escherichia coli ATCC8739 was evaluated over time in ready-to-eat (RTE) artichoke products processed or not with the probiotic strain Lactobacillus paracasei LMGP22043. Both probiotic and standard products (final pH about 4.0; aw=0.98) dressed with oil and packaged in modified atmosphere were inoculated with pathogens at a level of about 3 log CFU/g and stored at 4 °C for 45 d. Pathogens decreased in the probiotic product in 2 descent phases, without shoulder and/or tailing as observed by fitting the models available in the GInaFit software to the experimental data. S. enterica subsp. enterica was completely inactivated after 14 and 28 d in probiotic and standard products, respectively; E. coli was inhibited in the probiotic food at day 4 (count <detection limit (DL) 1 log CFU/g), while in the standard product, it survived until the end of experiment. L. monocytogenes decreased in the probiotic product at day 1 reaching values below the DL after 14 d, while 21 d were needed in the standard product, and survived in both samples until the end of the experimental period. Therefore, the probiotic strain, representing always more than the 93% of lactic acid bacteria (about 7 log CFU/g) during the entire experimental period, combines the efficacy of a protective culture, which can control the development of pathogens during storage with probiotic benefits.