EFFECTS OF PACKAGING MATERIAL AND STORAGE ON MICROBIAL LOAD OF COCOYAM FLOUR (SOUP THICKENER)

ABSTRACT

The effect of packaging material and storage on microbial load of cocoyam flour (soup thickener) was studied in this project. The cocoyam flour were examined microscopically. A solution of it was made and the serial dilution 1: 10-10 to 1: 10-5 were made from 9ml of the cocoyam flour (soup thickener). From the dilution, 1ml of each diluent was plated on nutrient agar and sabouround agar to permit the growth of common bacterial and fungi, from the cocoyam flour. Duplicated plate were for each dilution. The plate was swirled of gently to ensure even distribution of diluent and was incubated in inverted position of 370C for 24 hours. After 24 hours the colony were counted. Gram staining was carried out on the colonies and examines microscopically. Representative colonies were separated subcultured on nutrient agar slopes for confirmatory characterization of the organism present. Biochemical test for identification was also carried out. The result showed a mixed flora of bacteria and fungi includingcandida sp, Penicillium sp as the organism responsible for spoilage of cocoyam flour. The bacteria isolated from the sample was Bacillus sp.

CHAPTER ONE

1.0     INTRODUCTION

Cocoyam is a warm weather crop belonging to the monocotyledonous family of Araceae. It has two important genera as colocasia esculenta (Taro or Old cocoyam (Uguru, 2005) which have been extensively cultivated in most tropical regions with Nigeria as a major producer.

Cocoyam g rows well in rich and alluvial soil with large quantities of moisture and organic matter requiring average daily temperature of about 250C. It tolerates some degree of flooding or shade where an annual rainfall of about 200cm is ideal.

Cocoyam is a non true root when compared with cassava sharing under ground stem characteristics with yam although, classified as a corn instead of a tuber (Uguru, 2002). The multi purpose edible crop has recently received a great deal of attention from the advanced countries. The leaves of the edible crop can be conveniently consumed while the corn itself can be converted into a native food called ‘achicha’ or used as a soup thickener. The processes involved in converting the corn to a paste such as cleaning peeling, boiling until soft and finally pounding into a smooth paste is tedious and result, most working class ladies, bachelors and even house wives tend to avoid the difficult task despite the palatable nature of the soup. Consequently, means have been devised by researchers in converting the starchy root into flour hence, reducing the cooking time and tedious work involved (Ijeoma, 2007).