Effect of Different Preparatory Methods on Microbial Load of the Edible Frog Hoplobatrachus occipitalis from Aguleri, Anambra State, Nigeria

Abstract

With the increasing use of the edible frog Hoplobatrachus occipitalis as a delicacy in many parts of Nigeria, and food poisoning risks associated with contaminating microorganisms, it has become necessary to determine the best method of preparing the frog to eliminate/reduce microbial contamination before consumption. Fresh and smoke dried samples were bought from traders in Aguleri, Anambra East Local Government Area, Anambra State, Eastern Nigeria. Some fresh samples were oven dried in the laboratory. Enumeration, isolation, characterisation and identification of bacterial and fungal isolates were carried out using standard microbiological methods. The total heterotrophic bacterial counts for the fresh, smoke dried and oven dried samples were 2.1x105cfu/g, 1.8x105cfu/g and 2.5 x 105cfu/g respectively, while the total fungal counts were 6.2x104 cfu/g for the oven dried and 2.1x104cfu/g for both the fresh and smoke-dried samples. A total of forty-three (43) bacterial and fungal (including yeast) isolates were isolated from fresh samples of Hoplobatrachus occipitalis. The bacterial isolates include Acinetobacter sp., Bacillus sp., Escherichia coli, Flavobacterium sp, Micrococcus sp., Pseudomonas aerogenosa, Serratia sp., Staphylococcus aureus and S. epidermidis while the fungal isolates obtained include Aspergillus flavus, A. niger, A. tamari, Botrytis sp., Cladosporium sp., Geotrichum sp., Mucor sp., Penicillium chrysogenum, P. italicum, P. oxalicum and Trichoderma sp., Yeast isolates include Cryptomonas neoformis, Saccharomyces cereviaves and Saccharomyces sp. The smoke-dried samples had the least bacterial species while the fresh and smoke-dried ones had the least fungal species. Smoke-drying in hygienic conditions is highly recommended for consumers since they had least bacterial and fungal counts. This may greatly reduce the risk of food poisoning that might pose serious health challenges.
Keywords: Hoplobatrachus occipitalis, Microbial load, Edible frog, Aguleri,