Thermotolerant Escherichia coli contamination in vegetables from selected urban farms and wet markets in metro Manila, Philippines at the height of COVID-19 pandemic

Abstract

The fecal indicator bacterium Escherichia coli is one of the leading causes of foodborne diseases in the Philippines and its presence has been detected in agricultural crops especially vegetables, posing public health risks. Thus, surveillance and monitoring of locally available fresh produce is warranted to help address food safety issues. This study surveyed the presence of thermotolerant E. coli in vegetables in urban farms and wet markets during the peak of the COVID-19 pandemic (February 2021 to March 2022). A total of 419 vegetable samples from three urban farms and four major wet markets in Metro Manila were gathered. Using molecular and culture techniques, E. coli was detected in 13.60% of all the samples obtained. There was a significantly higher percentage of E. coli contamination from vegetable samples obtained from urban farms compared to samples obtained from wet markets. However, there was not enough evidence in this study to conclude that season (wet and dry); climatic variables such as average temperature, average rainfall, and average relative humidity; and physicochemical parameters of irrigation water (pH, temperature, salinity, turbidity, and dissolved oxygen) are correlated with E. coli contamination in fresh produce. This indicates that there might be other factors that directly impact the level of contamination in vegetables. Measures to improve surveillance and monitoring of contamination must be implemented to ensure proper risk assessment of E. coli contamination in agricultural settings and to prevent foodborne diseases.