Microbial and Parasitic Contamination on Fresh Vegetables Sold in Traditional Markets in Hue City, Vietnam

This study was conducted to evaluate microbial and parasitic contamination in twelve types of popular vegetables in Hue city. A total of 108 vegetable samples, equal numbers of young mustard greens, celery, amaranth, cilantro, water spinach, rice paddy herb, Vietnamese cilantro, basil, centella, lettuce, watercress, and iceberg lettuce were collected from three traditional markets in Hue city. All of samples were tested for total aerobic bacteria counts and E. coli by traditional culture-based methods. The Salmonella and parasites on the vegetables were detected by PCR technique and microscopic methods, respectively. All samples were highly contaminated with aerobic bacteria and E. coli. The aerobic bacteria counts ranged from 6.84 to 8.40 log CFU/g. Escherichia coli levels ranged from 5.47 - 6.88 log CFU/g. Salmonella was detected in 19/108 of test samples. Water spinach was found to have the highest contamination prevalence with Salmonella (55.56%). Contamination by multiple parasites was detected in all vegetable samples. The contamination rates of Fasciola, Ascaris, Trichuris and Clonorchis sinensis eggs were 83.33%, 85.19%, 64.81% and 16.67%, respectively. The oocysts of Cryptosporidium, Isospora and Cyclospora were found on the samples at rates of 47.22%, 27.78% and 27.78%, respectively. These bacteria and parasites may become potential sources of cross contamination and pose a serious risk to human health.