Isolation and Identification of possible pathogenic bacteria on carrots sold at community market, Ahmadu Bello University, Zaria

Abstract

Carrots (Daucus carota) are root vegetables that can be purple, red, yellow or white colour based on their pigmentation and variety. Due to the awareness of its high nutritional content such as vitamins, minerals and carotene, they are mainly consumed raw, possibly exposing one to the risk of being infected. Studies on the pathogenic Bacteria associated with fresh carrots sold in the community market at Ahmadu Bello University, main campus Samaru Zaria, were carried out using cultural techniques. Salmonella Shigella agar, MacConkey agar and Eosin methylene blue agar were the growth media for the isolation of the pathogenic Bacteria. Twelve fresh carrots were randomly bought from different food vendors in the community market, and then 10g of the outer layer (epidermal) scrapings were collected from each sample and homogenized in 90 ml of buffered peptone water. It was then serially diluted and 0.1ml of each 104 and 105 dilutions were plated on EMB, SSA, and MacConkey agar. Isolates were identified by gram staining and biochemical tests. The bacteria were identified to be Proteus species, Citrobacter species, Klebsiella species, and Salmonella species. Proteus spp was predominantly isolated among the bacterial isolates (41%) followed by Citrobacter spp (25%), Klebsiella spp (17%) and Salmonella spp (17%). These organisms may have been introduced to the carrots during growth, harvesting, handling, storage and distribution. The presence of the organisms is a public health risk because of the diseases known to be caused by them. It is therefore imperative that adequate hygienic practices be put in place during the cultivating and handling of carrots. A high level of susceptibility was observed in Ciprofloxacin at (100%) and Augmentin at (50%), while the high level of resistance was observed to be high in Gentamicin at (100%).