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Title: A Preliminary Study of the Fungal Flora of Ethiopian Cereal Grains with Special Emphasis on the Prevalence of Toxicogenic Groups
???metadata.dc.contributor.*???: Dr. Berhanu Abegaz
Abate, Dawit
Issue Date: Jun-1982
Publisher: Addis Ababa University
Abstract: Bacteria, moulds and yeasts on surface of cereal seeds ("teff", maize, barley and sorghum) were enumerated. Bacteria were in general found in greater numbers than moulds or yeasts per gram of grain. Tell harbours a higher number of bacteria (100,000 to 10,000,000 per gram) than the three cereal grains. Mould and yeast counts were not appreciably different - these fungi were found to occur in the range between 10,000 and 11000,000 /gm of grain. The mycoflora of the four cereal grains was studied, and in the survey 18 genera of fungi were identified. Azpergillus, rznicillims and Funarium were found to be the most prevalent genera, Tell was found to harbour the least number of fungal genera. Fusarium, TrichodeFaT, Rhizopus and Nucor were not found from any ofthe tell samples examined, Chaetomiuzi (35%), Pazicillium (35%), Alpergillus (25%), Alternarig (15%) and Helminthosporium (15%) were the most common genera in toff, Azprrgglms and Pencillium species were found in all grain types in a range of 25-60%. Fusarium was found to be moat associated with maize (62%) and sorghum (50%). Changes in the fungal flora were found to vary with storage period. sjorivm (80%), aternain (53%) and Ohdotomium (537.) were the most prevalent genera in maize and sorghum stored for less than 2 months. Aspersillus (100%), Sonicillium (42%) and Rhtepuo (42%) wore found to be dominant from long-term (greater than 6 months) stored grains. On the other hand, Aleprnarle, Cheetoinipp and Holorlethomortum were the genera absent from all long-term stored samples. The range 10-14% was the moisture level of moat grain samples examined. In general, toff and barley samples contained less moisture than maize and sorghum. The highest moisture content (16-17%) wan determined from sorghum samples. AoperzjIlus flayos was present in 24% of 110 grain samples examined. it was found to be more prevalent fn maize (33%) and sorghum (33%). It was found to he more cowmen in grain samples from Ammo (32%) and Dire Dille (10%) areas than from Addis Ababa (15%) or Shashemene (15%) samples. The anorexia producing ability of 20 isolates of A. flavors was investigated. Sixteen isolates (80%) were capable of producing eflatoxin B1 and C. It was also found chat all cereal grains provide a suitable substratum for aflatoxin production in vitro. Fuoarium aveum was found to bewoost prevalent in maize (35%), rare in barley (5%) and sorghum (7%) while none was isolated from teff. Out of the five Fusarium roseum isolates examined only one showed toxicity by the rabbit skin toxicity test. From other Fusarium app. 2 isolacos showed toxicity out *Utile seven tested. Ochratoxin was not detected in any of the Aspergillus and Pencillium isolates examined.
Description: A Thesis Submitted to School of Graduate Studies Addis Ababa University in Partial Fulfillment of the Requirements for the Degree Master of Science in Biology.
Appears in Collections:Thesis - Biology

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