Effect of extracting methods on micro-organisms characterization in orange juice

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Date

2021

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Publisher

International Commission of Agricultural and Biosystems Engineering (CIGR) Journal, China

Abstract

The objective of this experiment was to evaluate the micro-organisms count in the raw and processed orange fruits using the Pour Plate Method and the Spread Plate Method. The study objective was to extract the juice from fresh orange juice using a Juice extractor, to determine the microbial count of orange juice and orange fruit, and to identify and characterize the different microbes present in the raw orange and processed fruit (juice) using different methods. In this study, different samples of orange fruits/juice were analyzed using Pour Plate Method (PPM) and Spread Plate Method (SPM). Samples analyzed include Raw orange Fruit (RF) serving as control, Manually Extracted orange Juice (MEJ), Machine Extracted orange Juice (MAEJ), Pasteurized Machine Extracted orange Juice at 85oC (PMAEJ, 85oC) and Refrigerated Machine Extracted orange Juice at 4oC (RMAEJ, 4oC).The micro-organisms count considered include Total Heterotrophic Plate Count (THPC), Total Coliform Count (TCC), Total Faecal Coliform Count (TFCC), and Fungal Count (FC). A total of 15 micro-organisms were identified which wereAeromonashydrophila,Bacillussubtilis,Micrococcussp.,Staphylococcusaureus,Staphylococcusepidermis,Listeriasp.,Lactobacillus fermenti, Providenciasp., Klebsiellapneumonia, Enterobacteraerogenes, Sacchoronyeescereoisioe, Penicillium sp.,Aspergillusniger, Rhizopusstolonifer,and Nucorracemosus. In all the samples, SPM was able to isolate more micro-organisms than PPM. Raw oranges showed high number of microbial load than any of the four samples while pasteurized orange juice showed the least number of microbial loads. Generally, for all the samples, the THPC ranges from 1.81 x 104 to 0.16 x 104cfumL 1, TCC ranges from 0.23 x 103 to 0.00 x 103cfumL-1, FCC ranges from 0.00 x 101 to 0.00 x 101cfumL-1, and FC ranges from 0.90 x 104 to 0.00 x 104cfu mL-1for Pour Plate method. While for spread plate method, THPC ranges from 1.83 x 104 to 1.80 x 104cfumL-1, TCC ranges from 0.29 x 103 to 0.00 x 103cfumL-1, FCC ranges from 0.00 x 101 to 0.00 x 101cfumL-1, and FC ranges from 1.00 x 104 to 0.00 x 104cfumL-1.From the two methods used in isolating micro-organisms, it can be recommended that the spread plate method is a more reliable method than the pour plate method in evaluating micro-organisms as it was able to isolate more micro-organisms in all the samples than pour plate method.

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Keywords

orange, juice, coliform, plate, count

Citation

*Sunmonu, M.O*., Odewole, M.M., Sanusi, M.S. Ajala, O.E. and Oyedeji, H.F. (2021). Effect of extracting methods on micro-organisms characterization in orange juice. International Commission of Agricultural and Biosystems Engineering (CIGR) Journal, China. 23 (2); 229 – 238. Published by CIGR. https://cigrjournal.org/index.php/Ejounral/issue/view/101

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