Hiding in Fresh Fruits and Vegetables: Opportunistic Pathogens May Cross Geographical Barriers

Abstract

Different microbial groups of the microbiome of fresh produce can have diverse effects on human health. This study was aimed at identifying some microbial communities of fresh produce by analyzing 105 samples of imported fresh fruits and vegetables originated from different countries in the world including local samples (Oman) for aerobic plate count and the counts of Enterobacteriaceae, Enterococcus, and Staphylococcus aureus. The isolated bacteria were identified by molecular (PCR) and biochemical methods (VITEK 2). Enterobacteriaceae occurred in 60% of fruits and 91% of vegetables. Enterococcus was isolated from 20% of fruits and 42% of vegetables. E. coli and S. aureus were isolated from 22% and 7% of vegetables, respectively. Ninety-seven bacteria comprising 21 species were similarly identified by VITEK 2 and PCR to species level. E. coli, Klebsiella pneumoniae, Enterococcus casseliflavus, and Enterobacter cloacae were the most abundant species; many are known as opportunistic pathogens which may raise concern to improve the microbial quality of fresh produce. Phylogenetic trees showed no relationship between clustering of the isolates based on the 16S rRNA gene and the original countries of fresh produce. Intercountry passage of opportunistic pathogens in fresh produce cannot be ruled out, which requires better management.

Microbiological Quality of Organic and Conventional Leafy Vegetables

“…Some species observed in the present study in both organic and conventional leaves are epiphytic bacteria, which commonly colonize on the surface of plants [41]. Their occurrence was also documented by Al-Kharousi et al [42] in about 91% of vegetable samples.…”

Assessing the growth of Staphylococcus aureus and Escherichia coli on fruits and vegetables

“…Fresh fruits and vegetables that are exposed to these strains could represent a risk for public health. S. aureus and both E. coli (ETEC and EHEC) have been isolated on fruits and salads, including strawberries, fruit salads, radish, cabbage, lettuce, cucumber, carrot, spinach and sprouts [7][8][9][10][11][12][13]. These foods can be contaminated and microbial multiplication can occur at various stages throughout the processing chain, including during harvest, storage, transport and distribution [14].…”

Bacterial and parasitic contaminants of salad vegetables sold in markets in Fako Division, Cameroon and evaluation of hygiene and handling practices of vendors

“…There are documented outbreaks of human infections associated with the consumption of raw vegetables [19]. Trade has contributed to geographic spread of these pathogens [20]. Recent years have witnessed an increase in the frequency of occurrence of these infections.…”