Research Articles

Evaluation of bacterial and soil-transmitted helminth contaminations in lettuce and soil from agricultural farms and local markets, Cambodia

Panha CHHIM1, Kongkea PHAN1.*, Laingshun HUOY1.2.*

1 Food Chemistry Laboratory, Faculty of Science and Technology, International University, Phnom Penh 12101, Cambodia;
2Department of Bio-Engineering, Faculty of Engineering, Royal University of Phnom Penh, Cambodia.
*Corresponding author:,


Fresh lettuce is an essential component of a healthy and nutritious diet. However, consumption without proper washing could cause bacterial and soil-transmitted helminth (STH) infections. The present study was to investigate the occurrence of bacteria and STH eggs in lettuce and soil samples from farms and markets in Cambodia. A total number of 29 lettuce and 19 soil samples were analyzed for Aerobic Plate Count (APC), Escherichia coli (E. coli), Salmonella spp., Ascaris lumbricoides (A. lumbricoides), Trichuris trichiura (T. trichiura) and hookworm by using serial dilution and formalin ether concentration techniques following the standard methods. Analytical results revealed the mean of APC, E. coli and Salmonella spp. in all lettuce samples ranged from 5.78 to 8.95, 2.92 to 6.07 and 4.24 to 7.62 log CFU/g, respectively. The means of APC (7.61 log CFU/g), Salmonella spp. (6.32 log CFU/g) and E. coli (5.30 log CFU/g) in soil from organic farms were higher than those of APC 7.49 log CFU/g, Salmonella spp. (6.15 log CFU/g) and E. coli (4.65 log CFU/g) from conventional farms. Additionally, STH eggs recovered in organic lettuce were A. lumbricoides 50% (2/4) and T. trichiura 25% (1/4) and soil sample was A. lumbricoides 25% (1/4). Hookworms were found only in soil sample 6.66% (1/15) from conventional farm. None of the lettuce was positive for hookworm. This study suggests that fresh lettuce should be sanitized or heat-treated before consumption. Moreover, comprehensive health education and hygienic practices should be provided to farmers and sellers to minimize the consumers’ health risks of microbial infections.

Keywords: Lettuce; bacterial; soil-transmitted helminth eggs; conventional farm; organic farm; local markets.