Project Topics


1.1 Background to the Study

Locust bean, Parkia biglobosa is a tree of the genus Parkia in the family Fabaceae. In West Africa, its fruits are fermented to a condiment called ‘Soumbala’ or dawa dawa (Bonkounhou, 1987). The striking red spherical inflorescences which appear in the dry season, are often used by children for games (Burkill, 1996). The yellowish powder inside the seed pods is sweet and can be eaten without preparation and can also be made into drinks. The pods are boiled to male a black liquid used for sealing floors (Hall et al., 1996). It is a perennial deciduous tree with a height ranging from 7 to 20m, although it can reach 30m under exceptional conditions (Hopkins et al., 1984). Its seeds are fermented to make dawa dawa, a black strong smelling tasty food high in protein (Steinkraus, 1996).

In the tropics, especially in Nigeria, locust bean is processed locally into constable delish and is a part of traditional dishes in most parts of the country. It is sold in the Nigerian co sumables markets in two forms, the mashed and the unmashed locust bean. During the Nigerian processing of locust bean, salt is usually added to prevent microbial contamination  and growth. However, inspire of procedures engaged, locust bean could still harbour loads of microorganisms especially while handling. Moisture, ash, fiber, protein and fat in Parkia biglobosa infer the nutritional value of locust bean. Previous reports reveal that dawadawa is rich in protein, lipids and Vitamin B2 (Hopkins,1983) and that fermented beans are rich in lysine (Hopkins, 1983; Steinkraus,1996). According yo Hong et al., (1996). Parkia biglobosa seeds are used as coffee substitute and they are embedded in a mealy pulp sometimes called dozim, that is high in energy value. They contain up to 29% crude protein and up to 60% saccharose, rich in Vitamin C and high in oil content. (Ladokun et al., 2013).

The production of condiments is largely done on a traditional small scale household basis under highly variable conditions (Odunfa,1985). The fermentation is usually carried out in a moist solid state, involving contact with appropriate inocula of assorted microorganisms aided by the temperatures of the tropics. The desired state of the fermentation of the consents is indicated by the fermentation of mucilage and overtones of ammonia produced as a result of the breakdown of amino acids during the fermentation process (Omafuvbe et al., 2000). The characteristics ammonical odour and flavour of condiments enhance the taste of food which in which they are used especially the various soups used as accompaniment to starchy root and tuber diet (Simmons, 1976).


1.2 Problem Statement

During the Nigerian processing of Iru, salt is usually added to prevent microbial contamination and growth. However, inspire of these procedures Iru could still harbour loafs of microorganisms especially while handling. Hence, there is need to microbiologically evaluate the Iru in other to be able to ascertain its safety as a co dent used in food.


1.3 Objectives of the Study

The major objective of the study is the microbiological evelaution of ‘Iru’ sold in South West Nigeria.


1.4 Research Questions

(1) what is locust bean condiment?

(2) How are they produced?

(3) why the need yo microbiologically evaluate it ?


1.5 Significance of the study

The ultimate aim of eating food is to derive adequate nutrient and safety of the food. In Nigeria, the prevalence of food poisoning even though most cases are not reported demands that particular attention be paid to microbiological evaluation of food. This study gives a clear insight into the microbiological evaluation of locust bean condiment (Iru) sold in South West, Nigeria as it is widely consumed there.


1.6 Scope of the Study

This research focuses on the microbiological evaluation of Iru (locust bean condiment) sold in South West Nigeria.



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Burkill, H.M. (1995). The useful plants of West tropical Africa. 2nd Edition. Vole 3, Families J.L. Royal Botanic Gardens, Kew, United Kingdom. 857 pp.

Hall, J.B. Tomlinson, H.F, Oni, P.I, Buchy, M and Aebisch or, D.R (1996). Parkia biglobosa: A monograph. School of Agricultural and Forest Sciences Publication No 9, University of Wales, Bangor, United kingdom. 107 pp.

Hong, T.D., Linington, S. and Ellis, R.H. (1996). Seed storage Behaviour. A compendium. Handbooks for Genebanks: No. 4 IPGRI

Hopkins, H.C. (1983). The taxonomy reproductive biology and economic potential of Parkia (Leguminosae: Mimosoideae) in Africa Madagascar. Botanical journal of Linnean society 87: 135.

Ladokun, olusolaA, Adejuwon, Adekunlw. Nutritive andicrobial analysis of two types of fermented locust bean: Academic Arena journal, 2013; 5(5).

Odunfa, S.A.,1985. Microorganisms associated with the fermentation of African Bean (Sphenostis stenocarpa Hams). Food microbiology 8: 209-214.

Omafuvbe, B.O, Shunukan, C.O and Abiose, S.H. 2000. Microbiological and biochemical changes in the traditional feentation of soybean for soy daddawa, Nigerian food co diment. Food microbiology 17: 469-474.

Simmons, E.B. 1976. Calorie and Protein intake in three villages of Zaria province. May 1970- July 1971. Summary Miscellaneous paper. Institute of Agricultural Research. ABU, Zaria No. 55:151.

Steinkraus, K.H. (1996). Handbook of indigenous Fermented Foods. 2nd Edition. Marcel Dekker, Network 776 pp.