Fecal contamination in irrigation water and microbial quality of vegetable primary production in urban farms of Metro Manila, Philippines

Abstract

Microbial contamination of fresh produce can present a severe risk to public health. By conducting a rigorous survey of irrigation waters, the impacts of fecal contamination on the quality of produce could be assessed. In this study, surface waters were observed to be contaminated with Escherichia coli, Salmonella spp., and somatic coliphages. Culture methods show that out of 373 irrigation water, soil, and vegetable samples collected for a 1-year period, 232 (62.20%) were found positive for E. coli, 213 (57.26%) for somatic coliphages, and 2 (0.53%) for Salmonella spp. Out of 190 water samples, 167 (87.9%) were found to have E.coli, 174 (91.6%) have somatic coliphages, and 1 (0.5%) with Salmonella spp. In soil samples, 36 of 91 (39.6%) have E. coli, 31 (34.0%) have somatic coliphages, and none with Salmonella spp. Lastly, out of 92 vegetable samples, 29 (31.5%), 8 (8.7%), and 1 (1.1%) were found to have E. coli, somatic coliphages, and Salmonella spp., respectively. Molecular analysis confirmed the presence of bacterial contaminants. Seasonal weather conditions were noted to have an effect on the presence and number of these fecal indicator organisms. The observed data suggest that contaminated irrigation water may greatly affect the quality of fresh produce from these agricultural operations.

Antibiotic Resistance and Extended-Spectrum Beta-Lactamase Production of Escherichia coli Isolated from Irrigation Waters in Selected Urban Farms in Metro Manila, Philippines

“…The identity of the isolates was confirmed in a previous study [2] using a PCR assay that amplifies the ß-glucoronidase (uidA) gene which encodes an acid hydrolase that catalyzes the cleavage of a wide variety of 3-glucuronidases used by of E. coli [24].…”

“…A total of 212 culture-positive E. coli isolates that were previously collected from irrigation water, soil, and vegetable samples from six urban agricultural farms in Metro Manila, Philippines were used in this study [2]. The farms were small scale urban farms in Quezon City, Marikina City and Pasig City that are situated near residential areas and cultivate different vegetables that are sold in nearby wet markets.…”

“…In highly-urbanized and densely-populated areas, such as Metro Manila, Philippines, the use of highly-polluted surface waters for irrigation is widely practiced, especially as urban agriculture is gaining popularity as a tool to increase household income and meet subsistence food needs [2,19]. This necessitates the assessment and monitoring of the quality of surface waters used for irrigation.…”

“…In urban agricultural areas where there is limited water supply and high demand for clean water, irrigation water is usually sourced from surface waters contaminated with agricultural runoff, livestock and wildlife fecal material, wastewater discharge, and septic leakage [1,2]. Although surface waters are practical to use because of their availability and high nutrient content, they can be a potential source of fecal contaminants and pathogenic microorganisms that may be transferred to farm products, such as fresh produce, during irrigation [1][2][3].…”

Effect of Leaf Surface Chemical Properties on Efficacy of Sanitizer for Rotavirus Inactivation

“…This may occur during the preharvest period, when plants come into contact with contaminated irrigation water or runoff (14)(15)(16). Typically, fresh produce is stored at around 4°C to maintain postharvest shelf life and to prevent bacterial growth.…”