Use of Phyllosphere-Associated Lactic Acid Bacteria as Biocontrol Agents To Reduce Serovar Poona Growth on Cantaloupe Melons.

Foodborne illness associated with fresh, ready-to-eat produce continues to be a significant challenge to public health. In this study, we created a phyllosphere-associated lactic acid bacteria (PLAB) library and screened it via a high-throughput in vitro fluorescent assay to identify bacteria capable of inhibiting the growth of the pathogenic bacterium . One isolate, 14B4, inhibited the growth of by >45-fold in vitro; it was able to grow and persist on the surfaces of cantaloupe melons at both ambient (25°C) and refrigerator (5°C) temperatures. Isolate 14B4 inhibited the growth of on the surfaces of cantaloupes by >3 log when incubated at 25°C for 24 h and by >4 log when the cantaloupes were stored at 5°C for 3 days and the temperature was shifted to 25°C for 2 days. Genomic DNA sequence analysis of isolate 14B4 revealed that it was and that it did not contain any known antibiotic biosynthesis gene clusters, antibiotic resistance genes, or genes encoding any known virulence factors. Organic acid analysis revealed that produces substantial amounts of lactic acid, which is likely the inhibitory substance that reduced the growth of on the cantaloupes.