Isolation and characterization of fruits and vegetables spoilage microorganisms, Dambi Dollo town, Western Ethiopia

Abstract

Fruits and Vegetables are one of the essential diets of human beings, which are consumed widely. They are rich in vitamins and minerals. But, there are infected with saprophytic microorganisms after harvested. The aim of the study was to isolate and characterize spoilage microorganisms and identify associated risk factors of fruits and vegetables collected from Dambi Dollo town. The study was conducted from October 2018 to July 2019. The study used both interviewing and experimental work. Associated risk factors were identified by using interview, questionnaires, and observation regarding to handling practice, hygienic condition of fruit handlers, problems related to transportation. A total of forty samples, twenty from fruits and twenty from vegetables randomly collected from two areas of the town and were analyzed. In order to isolate and characterize bacteria and fungi cultural and morphological characterization and biochemical tests were performed. Antibiotic susceptibility test was done on isolated bacteria. All of the isolated bacteria were sensitive to Tetracycline and three of them were resistant to Imipenem . All fruits and vegetable samples were processed to mean viable count (cfu/ml) of bacteria. The highest mean viable count was found in lettuce (5.21 X 10 8 cfu/ml) followed by tomato (3.3 X 10 8 cfu/ml), avocado (1.8 X 10 8 cfu/ml) and orange (1.1 X 10 8 cfu/ml). From a total of forty samples five bacteria species were isolated including Escherichia species, Staphylococcus aureus, Pseudomonas species, proteus species and Bacillus species). Coliform (26.8%) was the most frequently selected from the samples followed by Staphylococcus aureus (21.4%), Pseudomonas species (19.6%), proteus species (16.1%) and Bacillus species (16.1%) Also from molds Aspergillus, Penicillium, Mucor, Rhizopus and Fusarium spp. were identified. Aspergillus species (34.48%) had the highest occurrence in the spoilt fruits and vegetables examined; while Rhizopus species (12.1%) had the lowest occurrence in the fruits and vegetables studied. The contamination of fruits and vegetables by bacteria and spoilage by fungi could be associated with a result of: poor handling practices in food supply chain, damage inflicted at a time of harvest; poor storage condition, distribution, marketing practices, transportation, packaging materials and vender’s hygiene were identified as the risk factors. Spoilage of fruits and vegetables are likely to be reduced by proper washing, store in clean places and carry to market by using appropriate carrying materials.