Microbiological Quality of Palm Wine (Elaeis guineensis) Sold Within Ikwo, Ebonyi State, South East, Nigeria

Chukwuma Victor Uzoh^1*, C. O. Nworie², P.C. Igwe³, C.S. Ugwuocha¹ and K.E. Aroh^1
*Correspondence: Chukwuma Victor Uzoh, Department of Microbiology, Alex-Ekwueme Federal University Ndufu- Alike Ikwo, Abakaliki, Ebonyi State, Nigeria, Email:

Keywords

Palm wine • Contamination • Fungal count • Fermentation • Hygienic practice

Introduction

Palm wine is referred to as a collective group of beverages that are obtained after the fermentation of sap of palm trees [1]. Over many years, the utilization of fermentation techniques has been a prominent as well as inexpensive preservation method especially during food shortages. Different kinds of locally fermented beverages exist worldwide in developing countries [2]. Microbial growth converts major and minor components by enzymatic actions which produced fermented beverages [3]. In tropical regions of Asia, Africa and Southern America where palm trees grow, fermented drink from palm trees is of much significance to people [4]. In Nigeria, most palm wine is tapped from three types of palm trees: E. guineensis (palm oil tree), R. vinifera and R. hookeri (raphia palms) [5]. Palm wine is collected twice a day, in the morning and evening where is can be consumed immediately or stored for sale the same day or next day [6]. The knowledge associated with the applied method will influence the quality attributes of the collected palm wine. Palm wine beverage has a high content of amino acid, zinc, iron and potassium. It is equally a good source of vitamin B1, B2, B3 and B6 and associated with increased sperm and breast milk production [7]. The nutritional profile of palm wine makes it a good medium for microbial growth. Due to rapid fermentation by microbes, hydrolysis of sucrose to fructose and glucose occurs within 24h. They are then converted to lactic acid, acetic acid and ethanol. This action reduces the pH of palm sap to 5 making it unacceptable to consumers as a drink. The aim of this study is to evaluate the microbial quality of some locally tapped palm wine within Ikwo Local Government Area, Ebonyi State.

Materials and Methods

Sample collection

Five (5) were samples of palmwine (E. guineensis) were collected from different local palm wine tappers in Ikwo, Ebonyi State, Nigeria using pre-sterilized 100ml capacity sterile sample bottles with perforated screw caps. The samples were immediately transported to the Laboratory in mixture of salt and ice block.

Isolation and microbial succession in palm wine

One milliliter (1 ml) aliquots of each palm wine was collected and used for 10-fold serial dilution with 0.1% (w/v) bacteriological peptone. 1 ml dilutions each of the samples were plated out in duplicates using spread plate method Cheesbrough M [8] on nutrient agar for total heterotrophic bacterial count, MacConkey agar for total coliform count and Sabouraud dextrose agar containing 0.05 mg/ml streptomycin for yeast count. The inoculated petri dishes were incubated at 30 ℃ for 24 h for bacteria and 48 h for yeast. Discrete colonies were subcultured and stored in agar slants.

Characterization of isolates

The isolates were grouped according to their colony morphology and microbial cell characteristics which were further subjected to biochemical tests. The suspected identities of the isolates were described by Cheesbrough M [8].

Results

The Table 1 shows the total fungal and bacterial count in palm wine samples sold in Ikwo, Ebonyi State. Sample B had the highest microbial contamination of 3.8 × 10³ and 1.8 × 10³ CFU/ml while sample E had the least contamination with the value of 1.2 × 10³ and 0.8 × 10³ CFU/ml respectively.

Table 2 This table showed the biochemical characteristics of the isolates (bacteria) from palm wine. A total number of five isolates were identified. This includes Lactobacillus sp, Micrococcus sp, Staphyloccus sp, Streptococcus sp, Bacillus sp.

From the Table 3, two fungal isolates were isolated and identified from the palm wine samples.

Discussion

The sap of palm wine trees is usually sweet and serves as a rich substrate for the growth of different types of microorganisms immediately after it is tapped. The sap undergoes rapid fermentation as a result of the proliferation of bacteria and yeasts which rapidly converts the sugar into different metabolites like lactic acid, ethanol and acetic acid [9]. From the microbiological quality of the palm wine investigated, the result showed that the samples harboured, different strains of microorganisms which consists of bacteria and fungi. The highest and lowest fungal count was for isolate B and isolate E with values of 3.8 × 10³ CFU/ml and 1.2 × 10³ CFU/ml. Similarly, the result of the bacterial count showed that isolate B had the highest count (1.8 × 10³ CFU/ml) while isolate E had the lowest count (0.8 × 10³ CFU/ml). These results corroborates the work of Karamoko D, et al. [4] and Obi CN, et al. [10] reported the presence of yeasts and bacteria in palm wine samples. The presence of different organisms that are not involved in the fermentation of the palm wine is an indication of the poor hygienic practices of the palm wine tappers, the materials and methods they used to perform this task. The level of awareness of the palm wine tappers or their knowledge on hygiene and hygienic practices influences the microbial content of the palm wine. However, the methods employed in tapping, collection and storage of palm wine determines the microbial content of the sweet cell sap of palm wine trees. The presence of these organisms is of public health concern since the palm wine is consumed in most parts of the state and outside the state due to its health, nutritional and social importance. Another area of public health concern is the questionable stream water used by the tappers to dilute the palm wine. There have been misconceptions among palm wine tappers and those who regularly patronize them that the degree of housefly or other flies that petch around where palm wine are stored makes the palm wine sweet instead of adopting sanitary measures to prevent the flies. However, most palm wine tappers believe that palm wine has traditionally inherent cleansing ability which makes it unnecessary to rinse the cups or containers used to dispense wines after use by an individual. There is need to sensitize the public on the consumption of these wines which will promote the quality of these products and avoid the health risk posed by the consumption of palm wine contaminated by microorganisms [11].

Conclusion

Palm wine, as a whitish liquid produced by the natural fermentation of the sap of palm tree (E. guineensis) has been consumed widely among which is pregnant mothers to enhance breast milk production. It is also consumed during ceremonies and other social activities. If not properly handled, they will constitute a major public health problem. However, there is need to monitor and promote the quality of these products because of their health and nutritional benefits.

Acknowledgement

None.

Conflict of Interest

None.

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