Microbiological Quality and Antibiotic Susceptibility Profile of Microorganisms Associated with Stored Vegetables in Port Harcourt

Abstract

Aim: Vegetables are good sources of nutrients such as minerals, oil, vitamins and carbohydrates and are used in preparing different delicacies such as soups and salads. This study was aimed at investigating the microbiological quality and antibiotic resistance pattern of microorganisms associated with stored vegetables in raffia baskets. Methodology: The vegetables were obtained from the Nigerian Stored Products Research institute (NSPRI) farm in Port Harcourt. Ten grams (10 g) each of fresh vegetables were homogenized differently in 90ml of sterile diluent. Aliquot (0.1 ml) of 10-3 and 10-5 dilutions of each vegetable sample was plated on nutrient agar plates and incubated at 37ºC for 24hours. Identified isolates were standardized using the 0.5 McFarland standard. This was done by transferring colonies of the test isolates into sterile 4 mL normal saline and comparing the turbidity of the isolate in the test tubes with the already prepared 0.5 McFarland. The disc diffusion method was used in determining the susceptibility pattern of the microorganisms against the antibiotics. In this method, the standardized inoculums were seeded aseptically on freshly prepared Mueller Hinton agar plates. Whatman discs which have been impregnated with different concentrations of the antibiotics were placed on the seeded plates and incubated at 37ºC for 18-24 hours.  Results: Zones of clearance or inhibition on plates were recorded. The genera Bacillus, Pseudomonas, Enterococcus, Enterobacter, Bordetella, Staphylococcus, Myroides, Escherichia, Serratia, Micrococcus and Acetobacter were identified as predominant microbes from the vegetables. Conclusion: Despite the high level of resistance to the antibiotics, Ciprofloxacin and Ofloxacin were the most effective and preferred drugs of choice for treatment of infections arising from the consumption of these vegetables. Adequate heating and blanching of vegetables is required at all times to prevent food poisoning.