Occurrence of Food-born Pathogen in Vegetables Irrigated with Sewage Water and Their Biological Treatment

THE USE of untreated sewage water in irrigation of vegetables represents a critical problem for the environment and human health. The present study was conducted to assess the extent of bacterial contamination of two vegetables (lettuce and tomato fruits) due to irrigation with sewage water in Belbais, Al-Sharqia Governorate, Egypt. The biological treatment process for the sewage water by two algal spp. (Spirulina platensis and Chlorella vulgaris) at two different concentrations of the algae (2.5ml/ and 10ml/500ml of sewage water) and at two different incubation periods (15 and 21 days) were done. Analysis of sewage and underground water for total coliform, fecal coliform, algae and heavy metals were done. Results showed that sewage water samples were highly contaminated than underground water. Twenty four vegetable samples (lettuce and tomato fruits) were collected from 2 fields, the first was irrigated with sewage water (6 lettuce and 6 tomato fruits samples) and the second with underground water (6 lettuce and 6 tomato samples). All samples were examined for E. coli and Salmonella spp. For lettuce irrigated with sewage 50% of samples were contaminated with E .coli while for tomato irrigated with sewage 66.6 of samples were contaminated with E. coli and Salmonella spp., but the tomato samples irrigated with underground were 33.3 and 50% of samples were contaminated with E. coli and Salmonella spp., respectively. The highest effect of the Spirulina platensis and Chlorella vulgaris to reduce the bacterial count (total coliform and fecal coliform) and to remove Lead (Pb) concentrations almost was of the higher concentrations with long time, while to remove the Cupper (Cu) was at the lower concentrations with the long time for the same algae.