Lettuce (Lactuca sativa L.) is a major ingredient used in many food recipes in South Korea.
Lettuce samples were collected during their maximum production period between April
and July in order to investigate the microbiota of lettuce during different seasons. 16S
rRNA gene-based sequencing was conducted using Illumina MiSeq, and real-time PCR was
performed for quantification. The number of total bacterial was greater in lettuce collected
in July than in that collected in April, albeit with reduced diversity. The bacterial
compositions varied according to the site and season of sample collection. Potential
pathogenic species such as Bacillus spp., Enterococcus casseliflavus, Klebsiella pneumoniae, and
Pseudomonas aeruginosa showed season-specific differences. Results of the network cooccurrence
analysis with core genera correlations showed characteristics of bacterial
species in lettuce, and provided clues regarding the role of different microbes, including
potential pathogens, in this microbiota. Although further studies are needed to determine
the specific effects of regional and seasonal characteristics on the lettuce microbiota, our
results imply that the 16S rRNA gene-based sequencing approach can be used to detect
pathogenic bacteria in lettuce.
Lettuce, foodborne illness, 16S rRNA gene, bacterial diversity