RESUMO
Background and Objective: Garri is a powdery carbohydrate-based food material of cassava root tubers (Manihot esculenta Crantz) consumed predominantly in West African countries. It can be processed with palm oil rich in carotenoid (Light-yellow) or without palm oil (Creamy-white). In Nigeria, garri is widely acceptable and consumed by both the poor, the middle men or average Nigerian, and also the rich because it serves as a major source of carbohydrate.The study aimed at detecting fungal strains that produce mycotoxins in garri sourced from Southern Ijaw Local Government Area of Bayelsa State.Materials and Methods:A total number of fifty freshly prepared and market displayed-garri samples were collected and processed using standard mycological techniques and Polymerase Chain Reaction from the 23 villages that constitute the LGA.Results:Results showed that the moulds isolated in yellow garri samples in this study were; Aspergillus spp9(37.50%),Cladosporiumspp 5(20.83%),Fusarium spp4(16.67%),Penicillus spp3(12.50%),Rhizopus spp2(8.30%) and Mucor spp1(4.17%),while those isolated in the white garri samples were; Aspergillus spp 6(25%), Penicilliumspp 8(33.3%), Cladosporium spp 4(16.7%), Rhizopus spp 2(8.3%),Mucor spp 1(4.1%), Alternaria spp 2(8.3%) and Fusarium spp 1(4.1%) with predominance of Penicilliumand Asperigellus species. Twenty samples subjected to molecular analysis to determine the Internal Transcribed Spacerregion (ITS) and characterization of the fungal strains were all positive (100%).Conclusion:Fungal contamination on garri mostly results from unhealthy post-processing activity basically from poor packaging and storage. Mycotoxins from fungal strains have serious health implications on humans therefore it is paramount that proper packaging and storage of this product is publicized to reduce its mycological contamination.
RESUMO
Histological studies were carried out to investigate the impact of some pathogenic organisms on infected cassava root after different periods of incubation. Cassava roots inoculated with Aspergillus niger, Rhizopus stolonifer, Aspergillus flavus, and Trichoderma viride showed progressive depletion of the starch grains in the cells and tissue maceration of the cassava root as the period of incubation increased. Cassava root inoculated with A. flavus showed tissue necrosis and slight fragmentation of the starch grains whereas, cassava tissues infected with A. niger showed tissue necrosis and general maceration of the starch grains within the tissue thereby creating empty spaces within the cells with no clear arrangement of the starch grains. Inoculation of the cassava tissues with R. stolonifer resulted in rapid loss of the starch grains and erosion of surrounding cell boundaries. Cassava tissue colonized by T. viride showed tissue necrosis and maceration of the starch grains. Healthy (uninoculated) cassava root tissue showed intact cells packed with large starch grains suggesting that in the host-parasite relationship, the pathogens established themselves inter and intracellularly in the parenchymatous cells of the cortex of the cassava root clearing them of starch grains, and resulting to poor yield and nutritional value of cassava and also economic loss.