Microbe loads in washed and unwashed vegetables’ water in samaru market, Nigeria

Abstract

The study investigated microbial infestation load of four vegetables; carrot, cucumber, lettuce and tomatoes (washed and unwashed), as well as water samples used for washing of these produce. The objective was to determine microbial load on vegetables, possible causes of contamination, as well as efficacy of anti-microbial agents in decontaminating microorganism on vegetables. The vegetables and water samples of 50g each and 100ml respectively were obtained from Samaru Market under aseptic conditions (in sterile plastic bags to eliminate cross contamination) and transported to the laboratory of the National Research Institute for Chemical Technology (NARICT), Basawa, Zaria, Environmental Technology Division, Microbiology Section and were preserved in iced cooler. The samples were analyzed bacteriologically by total viable count with the following results: Carrot 5.4x107 cfu/g unwashed and 4.7x104 cfu/g washed; cucumber 4.8x103 cfu/g unwashed and 1.8x103 washed; Lettuce 3.6.8x106 unwashed and 2.9x105 washed and Tomatoes 5.6x103unwashed and 3.4x104 washed. Water used to wash tomatoes 5.3x104 cfu/ml and water used to wash carrot, cucumber and lettuce 4.6x105 cfu/ml. Total fecal coliform count has the following results: carrot 3.9x105 cfu/g unwashed and 3.4.7x103 cfu/g washed; cucumber 2. 4x103 unwashed and 7.6x102 cfu/g washed; Lettuce 2.4x104 cfu/g unwashed and 8.2x103 cfu/g washed and Tomatoes 4.7x104unwashed and 4.4x103 cfu/g washed. Water used to wash tomatoes recorded 7.2x103 (cfu/ml) and water used to wash carrots, cucumber and lettuce 3.1x103 cfu/ml. The most probable number (MPN) of microorganisms was identified from surface of these vegetables and exceeded the World Health Organization (WHO) recommended standard for unrestricted farm produce. The result reveals that contamination of vegetables was attributable to use of contaminated water used to wash fresh produce, feaces and farmyard manures/animal waste used as manure and unhygienic handling by sellers. Appropriate management practices were recommended.