Antagonistic effect of probiotic bacteria against foodborne pathogens on fresh-cut pear

The use of probiotics as biopreservation agents of foodborne pathogens in food is becoming increasingly known. The aim of this work was to investigate the effectiveness of Lactobacillus rhamnosus GG (L rham. GG) and Lactobacillus acidophilus LA-5 (L. acidophilus LA-5) against Salmonella and Listeria monocytogenes in minimally processed pears during storage at 5, 10 and 20 degrees C at conditions simulating commercial application. Pear wedges were artificially inoculated with a suspension containing Salmonella, L. monocytogenes and/or the probiotic strains L rham. GG or L. acidophilus LA-5, packaged and stored at 5, 10 and 20 degrees C. Microorganisms were periodically enumerated. L acidophilus LA-5 did not shown any effect against pathogens. Salmonella was affected by co-inoculation with L. than GG at 10 and 20 C, which reduced the population approximately 2-log units. Moreover, L. monocytogenes population was reduced approximately 3-log units at each temperature in presence of L rham. GG. Probiotic populations were maintained throughout the experiment around 10(7)-10(8) CFU g(-1), which is in the range known to develop its probiotic role (10(6)-10(9) CFU g(-1)). Our results demonstrated that L. rham. GG is able to control Salmonella and L monocytogenes growth on fresh-cut pear.

Authors are grateful to Secretaria d’Universitats i Recerca del Departament d’Economia i Coneixement de la Generalitat de Catalunya (AGAUR fellowship 2015-FI-B100156 (M. Belén Iglesias)), Spanish Ministry of Science and Innovation (AGL-2012-38671 research project), and CERCA Programme (Generalitat de Catalunya) for their financial support.