Assessment of the Microbial Status of ‘OGI’ Subjected to Varying Storage Conditions
*1Olatunde, A. O., 1Ojo, R. O., 1Temikotan, T. & 1Omoniyi, E. I.
1Department of Biological Sciences, College of Natural and Applied Sciences, Achievers University, P. M. B.1030, Owo, Ondo State Nigeria
Email: olaposiolatunde@yahoo.com
ABSTRACT
Adequate food supply all the year round in most developing Nations has been seriously hampered by contamination, deterioration in storage, and inadequate storage facilities. Moisture, Relative Humidity and Temperature affect food in storage indirectly through their influence on the agents of biological deterioration and directly through physical and chemical processes. The microbial qualities of Ogi kept under three different conditions were assessed at the microbiology laboratory of Achievers University, Owo. The samples assessed were procured from local producers at the local market and taken to the laboratory in sterilized nylon bags for examination. Before analyzing the samples, they were placed under three storage condition viz; under water (Treatment 1 or T1), in refrigerator (Treatment 2 or T2) and air-dried into wettable powder (Treatment 3 or T3). All the samples were covered with aluminum foil to prevent cross contamination during handling. The samples were held under these conditions for 1 week after which subsamples were taken from the original samples for analysis. The subsampling and analysis procedures were replicated three times at weekly intervals. The water in T1 was changed every 24 hours to prevent the growth of fungi. The three media; Nutrient Agar (NA), Potato Dextrose Agar (PDA) and MacConkey (MA) used for the analysis were prepared according to manufacturer’s specification. Twenty eight grams (28g) of Nutrient agar powder was weighed using the weighing balance and was dissolved in 1 litre of sterile distilled water in a conical flask. The mixture was thoroughly mixed and boiled to ensure complete dissolution of the powder. The conical flask was corked with cotton wool and later with aluminum foil and sterilized by autoclaving at 1210C for 15 minutes. The same procedure of preparation was used for the preparation of Potato Dextrose Agar (PDA) and MacConkey Agar (MA) with thirty nine grams (39g) and fifty two grams (52g) of powdered media respectively. Identification and characterization of bacteria isolates was done based on morphology, staining reactions and biochemical tests. Fungi identification was based on morphology and microscopic examinations. The results of the research indicated that storage conditions exert a great deal of effect on the microbial qualities of Ogi. The bacterial isolates identified in the three samples include E. coli, Lactobacillus sp, Staphylococcus sp, Flavobacterium sp and Vitrobacterium sp. The results shows that Ogi samples under water (T1) has the highest number of isolates followed by refrigerated Ogi sample (T2) and dried Ogi sample (T3) in that order. The trend indicates that moisture and temperature are important factors required by microorganisms to thrive in stored food commodities.
Keywords: Microbial, Assessment, Maize, Ogi, Storage
