Abstract

Food borne illnesses have major social and economic impacts. Escherichia coli O157:H7 is associated with food borne illness in human beings. It has been an important food borne pathogen that causes food borne diseases such as diarrhea, hemolytic uremic syndrome and hemorrhagic colitis. This study was conducted to detect the presence of E. coli O157: H7 in different food samples sold in Nigerian local markets. A total of 60 different food samples (3 each of meat, fufu, waterleaf, pumpkin, carrot, tomatoes, meat pie, yoghurt, watermelon, cucumber, groundnut, cabbage, garden egg, bread, okra, apple, chicken, unpasteurized milk, salad and pawpaw) were collected randomly from different markets in Calabar, Nigeria. The samples were analyzed using standard microbiological techniques. Isolation was carried out using pour plate technique on sorbitol MacConkey agar. The isolates were identified by morphological and biochemical tests. Out of the 60 samples investigated, 36 (60%) were found to be contaminated with E. coli O157:H7 while 24 (40%) were negative by conventional methods. All the isolates obtained from the samples were subjected to various biochemical tests and were all confirmed to be E. coli O157:H7. The occurrence of E. coli O157:H7 serotype in these food products indicates that there may be a potential risk for public health from consuming these foods. This study clearly indicated the need for proper handling and processing of food products especially ready to eat food products. It is also important that at household level proper hygienic measures should be taken to avoid cross contamination.

Key words: Escherichia coli O157:H7, diarrhea, food borne illnesses, food samples, hemorrhagic colitis.