Comparative Analysis of Acetobacter aceti Prevalence in Ripe Fruits Sold at Ozuoba Market, Port Harcourt, Rivers State
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Abstract
The study screened for Acetobacter aceti in ripped fruits marketed in Ozuoba due to the alleged use of Calcium Carbide, a chemical for fruit ripening. Twenty-five (25) samples each of banana, orange, watermelon, and pineapple were purchased and taken to the labouratory for microbiological investigation. The fruit samples were cultured on Glucose Yeast-extract Calcium Carbonate (GYC) media, Gram-stained, and characterized; biochemically and morphologically. Results showed that watermelon had the highest A. aceti load of 5.9×10³ CFU/ml and a heterotrophic fungi load of 4.0×10³ CFU/ml. Banana had the lowest A. aceti load of 1.0×10³CFU/ml and 1.6×10³CFU/ml load of heterotrophic fungi. Morphological characterization revealed non-pigmented, convex, shiny, rod-shaped colonies of A. aceti, consistent with previous literature. Biochemical tests indicated catalase positivity and glucose fermentation capability, while reactions for oxidase, indole, gelatinase, and nitrate reduction were negative. The microbial loads in all fruits investigated exceeded WHO's recommended threshold of 10² CFU/ml. Frequency data showed A. aceti was most frequently recovered from watermelon (20%) and least from pineapple (4%). However, the difference between fruit type and microbial presence was not statistically significant (χ²=3.196, P>0.05). The high A. aceti load recovered, specifically, in watermelon, suggests a significant health risk particularly, due to the opportunistic nature of A. aceti. In addition, the high prevalence of A. aceti in watermelon over other fruits, indicated ripening may have been induced. Acetobacter aceti in watermelon is of health risk to consumers. The study therefore discourages ripening of fruits through inducement and calls for further investigation of A. aceti in other ripened fruits not investigated in this study.
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References
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