, Volume 134, Issue 2, pp 109–114 | Cite as

High incidence of Aspergillus flavus and aflatoxins in stored groundnut in Ghana and the use of a microbial assay to assess the inhibitory effects of plant extracts on aflatoxin synthesis

Mycotoxicoses and Mycotoxins


Groundnut samples from 21 selected markets in the 10 regions of Ghana yielded high levels of the aflatoxigenic fungus Aspergillus flavus on half-strength potato dextrose agar. The fungus was associated with 31.7 and 12.8%, respectively, of all damaged and undamaged kernels assayed. Only 0.24% of total kernels assayed yielded A. parasiticus. Other fungi detected from total kernels assayed were A. niger (34%), A. candidus (1.45%), A. tamarii (3.93%), A. ochraceous (5.26%), Fusarium spp. (1.7%) Penicillium spp. (5.19%), a Mucor sp. (2.3%), a Trichoderma sp. (0.2%), Rhizopus stolonifer (12%) and certain unidentifiable fungi (11.72%). Total aflatoxin levels ranging from 5.7 to 22, 168 ppb were identified with damaged kernel samples. The mycotoxin was not detected in 50% of undamaged kernel samples tested and very low levels mostly ranging from 0.1 to 12.2 ppb were associated with the undamaged samples that tested positive for aflatoxins. In a novel in vitro microbial assay to determine the effectiveness of certain plant extracts against aflatoxin synthesis, extracts from Xylopia aethiopica, Monodera myristica, Cinnamomum verum and Piper nigrum permitted fungal growth in 1.5% potato-dextrose broth while completely suppressing NOR formation. These extracts, however, could not suppress NOR formation in a yeast extract sucrose medium.

Key words

aflatoxin norsorlorinic acid plant extracts 


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  1. 1.
    Anon. Agriculture in Ghana; Facts and Figures. Policy Planning, Monitoring and Evaluation. Ministry of Agriculture Ghana, 1991:30 pp.Google Scholar
  2. 2.
    Enomoto M, Saito M. Carcinogens produced by fungi. Ann Rev Microbiol 1972; 26: 279–312.CrossRefGoogle Scholar
  3. 3.
    Cheng CT. Perak, Malaysia, mass poisoning. Tale of the Nine Emperor Gods and rat tail noddles. Am J Forensic Med Pathol 1992; 13:(3) 261–263.CrossRefPubMedGoogle Scholar
  4. 4.
    Beardwood CJ. Detection of aflatoxin in groundnuts in Accra. Ghana Med J 1964; 3(1): 87–88.Google Scholar
  5. 5.
    Mintah S, Hunter RB. The incidence of aflatoxin found in groundnuts (Arachis hypogea L.) purchased from markets in and around Accra, Ghana. Peanut Sci 1979; 5: 13–16.CrossRefGoogle Scholar
  6. 6.
    Bilgrami KS, Misra RS, Sinha KK, Singh P. Effect of some wild and medicinal plant extracts on aflatoxin production and growth of Aspergillus flavus in liquid culture. J Ind Botan Soc 1980; 59: 123–126.Google Scholar
  7. 7.
    Mabrouk SS, El-Shayeb NMA. Inhibition of aflatoxin production in Aspergillus flavus by natural coumarins and chromones. World J Microbiol and Biotechnol 1992; 8: 60–62.CrossRefGoogle Scholar
  8. 8.
    Lee LS, Bennett JW, Goldblatt LA, Lundin RE. Norsolorinic acid from a mutant strain of Aspergillus parasiticus. J Am Oil Chemists Soc 1971; 48: 93–94.CrossRefGoogle Scholar
  9. 9.
    Keller NP, Butchko RAE, Sarr B, Phillips TD. A visual pattern of mycotoxin production in maize kernels by Aspergillus spp. Phytopathology 1994; 84: 483–488.CrossRefGoogle Scholar
  10. 10.
    Pons WA. High pressure liquid Chromatographic determination of aflatoxin in corn. J Assoc Official Analytic Chemists 1979; 62: 586–594.Google Scholar
  11. 11.
    Shepherd MJ, Gilbert J. An investigation of HPLC post-column iodination conditions for the enhancement of aflatoxin B1 fluorescence. Food Additives and Contaminants 1984; 1: 325–335.PubMedGoogle Scholar
  12. 12.
    Boadu V. Effects of some plant extracts on aflatoxin synthesis by and growth of Aspergillus parasiticus Speare in liquid media [Dissertation]. Kumasi Ghana: Faculty of Agriculture, U.S.T., 1993.72 pp.Google Scholar
  13. 13.
    Joffe AZ, Borut SY. Soil and kernel mycoflora of groundnut fields in Israel. Mycologia 1966; 58: 629–640.CrossRefPubMedGoogle Scholar
  14. 14.
    McDonald D. Fungal infection of groundnut fruit after maturity and during drying. Trans Br Mycol Soc 1970; 59(3): 461–472.CrossRefGoogle Scholar
  15. 15.
    Frazier WC, Westhoff DC. Food Microbiology, 3rd ed. New Delhi (India): Tata McGraw-Hill Publishing Company 1987: 540 pp.Google Scholar
  16. 16.
    Awuah RT. Fungitoxic effects of extracts from some West African Plants. Ann Appl Biol 1989; 115: 451–453.CrossRefGoogle Scholar
  17. 17.
    Tripathi RD, Banerji R, Sharma ML, Balasubrahmanyan VR, Nigam SK. Toxicity of essential oil from a new strain of Ocimum gratissimum (clocimum) against betelvine pathogenic fungi. Horticultural Abstracts 1986; 56: 288.Google Scholar
  18. 18.
    Sainsbury M, Sofowora EA. Essential oils from the leaves and inflorescence of Ocimum gratissimum. Phytochemistry 1971; 3309–3310.Google Scholar
  19. 19.
    Purseglove JW. Tropical Monocotyledons. Vol. 1 & 2 combined. London: Longman, 1975; 607 pp.Google Scholar
  20. 20.
    Boakye-Yiadom K, Fiagbe NIY, Ayim JSK. Antimicrobial properties of some West African medicinal plants IV. Antimicrobial activity of Xylopic acid and other constituents from the fruits of Xylopia aethiopica (Anonaceae). Lloydia 1977; 40: 543–545.PubMedGoogle Scholar

Copyright information

© Kluwer Academic Publishers 1996

Authors and Affiliations

  1. 1.Department of Crop ScienceUniversity of Science and TechnologyKumasiGhana
  2. 2.Food Research InstituteAccraGhana

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