Meddling with a cultrural heritage: Traces of salicylate in adulterated palm wine and health implications

Abstract

Palm wine is an alcoholic beverage identified with various cultures in Africa by different names playing
an important role in the tradition, religious and cultural beliefs of the people. Often obtained by tapping
the cut flower of palm trees, this alcoholic beverage can serve as sources of some vital nutrients. Palm
wine samples bought from fifteen (n = 15) different vendors located in different parts of Ibadan, Nigeria
were analyzed for glucose, alcohol and salicylate content. Controls were freshly tapped, undiluted
palm wine from five different tappers (n = 5). The mean ± SEM glucose concentration (mg per 100 ml)
15.57 ± 4.94 of regularly sold palm wine is significantly lower than 376.40 ± 9.92 mg per 100 ml
observed in freshly tapped undiluted palm wine. The mean ± SEM alcohol concentration (mg per 100
mℓ) 117.71 ± 11.28 of the regularly sold palm wine is significantly higher than 33.72 ± 2.68 (mg per 100
mℓ) observed in freshly tapped palm wine. Traces of salicylate were found in samples of some of the
regularly sold palm wine but absent in the freshly taped. The mean ± SEM salicylate concentration (mg
per 100 mℓ) is 4.5 × 10-2 ± 1.6 × 10-2 for regularly sold palm wine. This value had no significant
difference when compared with 0.00 ± 0.00 (mg per 100 mℓ) observed in freshly tapped palm wine.
However, continued consumption of palm wine with salicylate content might lead to exposure to
chronic salicylate poisoning. Saccharomyces cerevisiae to which fermentation of palm sap to palm
wine is usually attributed was the fungal isolate in both the regularly sold and freshly tapped palm
wine. A ripple health effects can ensue from intoxication due to product’s alcoholic content, unguided
drinking behaviour and lack of effective monitoring of product quality. Maintaining this symbolic
commodity of immense indigenous values in its original unadulterated form for consumption is
advocated.

Full text

African Journal of Food Science Vol. 5(9), pp. 536-540, 15 September, 2011
Available online http://www.academicjournals.org/AJFS
ISSN 1996-0794 ©2011 Academic Journals
Full Length Research Paper
Meddling with a cultural heritage: Traces of salicylate in
adulterated palm wine and health implications
Bisi-Johnson, M. A.
1
*, Adejuwon, A. O.
1
, Ajayi, A. O.
1
, Uaboi-Egbenni, P. O.
2
and Adefisoye, M. A.
1
1
Department of Microbiology, Obafemi Awolowo University, Ile-Ife, Osun State, Nigeria.
2
Department of Microbiology, School of Mathematics and Natural Science, P. M. B. 5050, Thohoyandou, Limpopo
Province, South Africa.
Accepted 19 July, 2011
Palm wine is an alcoholic beverage identified with various cultures in Africa by different names playing
an important role in the tradition, religious and cultural beliefs of the people. Often obtained by tapping
the cut flower of palm trees, this alcoholic beverage can serve as sources of some vital nutrients. Palm
wine samples bought from fifteen (n = 15) different vendors located in different parts of Ibadan, Nigeria
were analyzed for glucose, alcohol and salicylate content. Controls were freshly tapped, undiluted
palm wine from five different tappers (n = 5). The mean ± SEM glucose concentration (mg per 100 ml)
15.57 ± 4.94 of regularly sold palm wine is significantly lower than 376.40 ± 9.92 mg per 100 ml
observed in freshly tapped undiluted palm wine. The mean ± SEM alcohol concentration (mg per 100
mℓ) 117.71 ± 11.28 of the regularly sold palm wine is significantly higher than 33.72 ± 2.68 (mg per 100
mℓ) observed in freshly tapped palm wine. Traces of salicylate were found in samples of some of the
regularly sold palm wine but absent in the freshly taped. The mean ± SEM salicylate concentration (mg
per 100 mℓ) is 4.5 × 10
-2
± 1.6 × 10
-2
for regularly sold palm wine. This value had no significant
difference when compared with 0.00 ± 0.00 (mg per 100 mℓ) observed in freshly tapped palm wine.
However, continued consumption of palm wine with salicylate content might lead to exposure to
chronic salicylate poisoning. Saccharomyces cerevisiae to which fermentation of palm sap to palm
wine is usually attributed was the fungal isolate in both the regularly sold and freshly tapped palm
wine. A ripple health effects can ensue from intoxication due to product’s alcoholic content, unguided
drinking behaviour and lack of effective monitoring of product quality. Maintaining this symbolic
commodity of immense indigenous values in its original unadulterated form for consumption is
advocated.
Key words: Palm wine, alcohol, salicylate, Saccharomyces cerevisiae, culture, health.
INTRODUCTION
Palm wine is a symbolic alcoholic beverage which plays
an important role in the culture of the people of Africa. It
*Corresponding author. E-mail: jumokade@yahoo.co.uk. Tel:
+27(0)766813494. Fax: 0866613494.
Abbreviations: MYEGA, Malt yeast extract-glucose agar; SDA,
sabouraud dextrose agar; ADH, alcohol dehydrogenase; NAD,
nicotinamide adenine dinucleotide; SD, standard deviation;
SEM, standard error of means.
forms an important part of social events in cultures with
slight variations in each region. This alcoholic beverage
comes by different names (SCTD, 2006), in different
cultures as indicated in Table 1. It is one of the forest
food resources in most countries in Western, Central
Africa and other tropical regions such as Asia and
Southern America (Uzochukwu et al., 1994). Tradi-
tionally, more than 10 million people in West Africa
consume palm wine FAO (1998). A comparison of
consumption of palm wine in this part of Africa with
different alcoholic drinks such as beer, locally fermented

Bisi-Johnson et al. 537
Table 1. Different names of palm wine by regions in Africa.
Local names African region
Emu, oguro, nnmaya ngwo Nigeria
Nsafufuo, doka, akpeteshe Ghana
Ubusulu Southern Africa
Malafu ya ngasi (kikongo) Democratic republic of Congo
Mimbo, matango Cameroun
Poyo Sierra Leone
Toutou Gabon
Lāgbi Libya
Adapted from (www.itdg.org/html/technical_enquiries/ docs/ toddy_palm_wine).
wine and locally distilled gin by Fatoye and Morakinyo
(2002) showed that most commonly used alcoholic
beverages was palm wine (60.1% of users). In Southern
Africa, palm wine is consumed by rural people in
Maputaland, Natal, South Africa (Cunningham and
Wehmeyer,
1987). This alcoholic beverage is obtained
commonly from different genera of palm tree namely
Elaeis guineensis, Raphia vinifera and Raphia hookeri in
most part of Africa where forest vegetation exists but
from Hyphaene coriacea and Phoenix reclinata in
Southern Africa. It is obtained by tapping the stalk of
male inflorescence or from the crown of leaves of young
palm trees (Anonymous, 1992). Palm sap is transparent
whereas, palm wine, the fermented sap, is whitish and
has a pH of about 3.6 and alcohol contents of 3.3 to
4.0%, depending on the stage of fermentation at which
the wine is consumed (Lasekan et al., 2007).
It is an important source of simple sugars and amino
acids such as nicotinic acid, vitamin C, thiamin, and
riboflavin. It is also rich in protein (Ezeagu and Fafunso,
2003) and full of a dense population of yeast (Bassir and
Maduagwu, 1978)
as well as some bacteria. These
microorganisms which have been reported to have
stemmed from various sources such as tapping
equipment, containers and the environment (Faparunsi
and Bassir, 1972), metabolize the sugars in the fresh
wine into various organic acids and alcohols (Bassir,
1962). The alcohol content of fermented wine can rise up
to 4% within an hour or two and ranges from 1.5 to 2.1%
at about 24 h while a longer fermentation produces
vinegar (Odunfa, 1985).
Palm wine serves as a source of
income to both tappers and vendors who for the sake of
maximizing their profit margin engage in various forms of
manipulations to the palm wine which leads to
adulteration of the product. Palm wine is diluted with
water by vendors and to maintain the required taste,
substances such as sugar is added. Some of the
consequential product of adulteration is presumed to
contain salicylate and high alcoholic content. Salicylate is
known to have toxic effect at a certain level of exposure
with a ripple health effects (van Heijst and Dijk, 1991).
Alcoholism is associated with various problems ranging
from physical, social to medical disorders. Alcohol is
considered to contribute substantially to diseases and
disability (WHO, 2002). Based on the high consumption
of palm wine in Nigeria (WHO, 2001), coupled with the
fact that some unscrupulous retailers use various
chemicals of unknown composition for the artificial
production of palm wine; this study was designed to
identify possible products of this local drink containing
potential salicylate contamination. Also, since micro-
organisms are responsible for the different taste and
constituent of palm wine at varying stages, study of the
microbial content believed to be involved in the
fermentation that was carried out.
MATERIALS AND METHODS
Sample collection
A total of fifteen samples of palm wine (n = 15) were obtained from
fifteen different sellers located in various parts of Ibadan, Nigeria.
Five other freshly tapped samples (n = 5) served as controls.
Sample were collected into sterile containers and brought to the
laboratory for mycological and biochemical analysis.
Culture conditions
Media for mycological isolation were malt yeast extract-glucose
agar (MYEGA) and Sabouraud dextrose agar (SDA). A loopful of
palm wine was streaked on MYEGA (5% w/v malt extract, 0.5% w/v
mycological peptone and 1.5% w/v agar, Fluka) and incubated at
28°C. Plates were examined daily for growth and identification was
by standard procedure. A commercial strain of baker’s yeast was
included as control (Beuchat et al., 1986; Larone, 1987).
Identification of yeast
Air-dried slides were prepared from culture plates. Following Gram
staining, microscopic examination was carried out. Identification of
the yeast was based on morphology as well as any visible internal
or budding cells structure. Classification guide according to Larone
(1987) was used. Following gram staining and microscopic

538 Afr. J. Food Sci.
examination, yeast colonies were picked up and sub-cultured on
MYEGA.
Biochemical analysis
Alcohol determination
Measurement of alcohol content was by a quantitative assay based
on the oxidation of ethanol to acetaldehyde by alcohol
dehydrogenase (ADH) in the presence of nicotinamide adenine
dinucleotide (NAD). The absorbance of the resulting solution was
measured at 340 nm against reagent blank and a Calibration graph
of absorbance was constructed against palm wine ethanol
concentration by analysis of the standard ethanol solutions and the
concentration of ethanol in the sample was calculated (WHO,
2008a).
Glucose analysis
Glucose was analyzed by a modified Trinder color reaction using
RAI-CHEM
TM
Glucose Reagent, Enzymatic 500 nm. This method for
the determination of glucose employs glucose oxidase and a
modified Trinder color reaction, catalyzed by the enzyme
peroxidase. Glucose is oxidized to D-gluconate by glucose oxidase
with the formation of an equimolar amount of hydrogen peroxide. In
the presence of peroxidase, 4-aminoantipyrine and p-hydro-
xybenzene sulfonate are oxidatively coupled by hydrogen peroxide
to form a quinoneimine dye, intensely colored in red. This was then
quantitated spectrophotometrically. The intensity of color in the
reaction solution is proportional to the concentration of glucose in
the sample (BeMiller, 2003; Powers, 2003).
Salicylate content
5 ml of Trinder's reagent
1
was added to 1 ml of sample or standard,
mixed and the absorbance measured at 540 nm against a sample
blank. The salicylate concentration was then calculated from the
graph obtained on analysis of the salicylate standards (WHO,
2008b).
Statistical analysis
Microsoft Excel (2003) package was used for statistical analysis
employing the independent sample t-test. Summary statistics such
as mean, standard deviation (SD) and standard error of means
(SEM) were computed. Significant tests were carried out at the 0.05
level of significance. It is concluded that there is significant
difference if the probability associated with the t test (p) is less than
the level of significance (that is, p< 0.05).
RESULTS AND DISCUSSION
The results show that the glucose concentration in the
regularly sold palm wine is lower than the concentration
observed in the freshly tapped. The alcohol concentration
in the regularly sold palm wine is higher than the
1
Trinder's reagent (a mix of 40 g of mercuric chloride dissolved in 850 ml of
purified water with 120 ml of aqueous hydrochloric acid (1 mol/l) and 40 g of
hydrated ferric nitrate, and dilute to 1 L with purified water).
concentration observed in the freshly tapped (p =
0.0005), hence there was significant difference between
alcohol content of the two types of palm wine. Studies
have shown that the fungi Saccharomyces cerevisiae is
capable of fermenting glucose to alcohol (Lasekan et al.,
2007). This probably accounts for the higher glucose but
lower alcohol contents in the freshly tapped than in the
regularly sold palm wine. The higher alcohol content
which is therefore observed in the regularly sold palm
wine is an indication that the palm wine must have been
tapped the days before being sold. This corroborates
previous reports that high level glucose in fresh palm sap
is fermented gradually into alcohol with increasing hours
or days (Odunfa, 1985). Traces of salicylate were
observed in the regularly sold palm wine but absent in the
freshly tapped (Tables 2 and 3). A comparison is shown
in Table 4. The expected organic acids in palm wine as
predetermined by Odunfa (1985) are lactic acid, acetic
acid and tartaric acid. The presence in the over the
counter palm wine of salicylate is an indication of illicit
adulteration. Assessment of both types of palm wine
following isolation showed a pure culture of gram positive
oval shape yeast, occurring in clusters with some
budding cells.
This confirmed presence of S. cerevisiae which were
observed in both regularly sold (Table 2) and freshly
tapped palm wine (Table 3). Previous reports have
shown that the high sugar content of the palm sap
selectively favours the growth of yeasts amidst the mixed
microorganisms associated with the product (Odunfa,
1985). Furthermore, since palm wine is an excellent
substrate for microbial growth and is not subjected to any
form of sterilization such as pasteurization or heating, it is
therefore, essential that proper hygienic collection
procedures are followed to prevent contaminating
bacteria from competing with the yeast and producing
acid instead of alcohol (Fellows, 1997).
Salicylate (Salicylic acid) a common pain reliever or an
analgesic was a powder extracted from the bark of
willows to treat pain and reduce fever. In the year 2004,
the United States poison center reported over 40,000
exposures to salicylate-containing products (Chyka et al.,
2007). Besides the aspirin, a common source of
salicylate, various other sources of salicylate poisoning
according to Reingardienė and Lažauskas (2006) are an
excessive application of topical agents, ingestion of
salicylate containing ointments, use of keratolytic agents
or agents containing methyl salicylate (for example, oil of
wintergreen). Most of these preparations are liquid, highly
concentrated and lipid soluble, and, therefore, they are
able to provoke a severe, rapid salicylate poisoning.
Presence of salicylate in palm wine, a local alcoholic
beverage may thus serve as another source of exposure
to this chemical.
The effect of exposure might be more in chronic
alcoholics and could probably be a source of chronic

Bisi-Johnson et al. 539
Table 2. Mycological and biochemical analysis of regularly sold palm wine (experimental).
Alcohol
(mg per 100 mℓ
-1
)
Glucose
(mg per100 mℓ
-1
)
Salicylate
(mg per100 mℓ
-1
)
Isolate
188.5 Nil 0.20 -
129.0 5.3 0.05 Saccharomyces cerevisiae
119.0 9.6 0.00 -
96.8 22.4 0.00 -
34.6 5.2 0.00 -
90.4 36.5 0.00 Saccharomyces cerevisiae
83.7 40.2 0.02 -
96.8 64.2 0.02 -
102.6 5.3 0.00 Saccharomyces cerevisiae
151.4 Nil 0.03 Saccharomyces cerevisiae
77.5 25.6 0.00 Saccharomyces cerevisiae
94.5 Nil 0.12 -
175.2 Nil 0.16 -
140.4 19.2 0.06 -
185.2 Nil 0.02 -
Mean 117.71 15.57 4.53 × 10
-2
S. D 43.69 19.15 6.4 ×10
-2
S. E 11.28 4.94 1.0 × 10
-2
n 15 15 15
Table 3. Mycological and biochemical analysis of freshly tapped palm wine (controls).
Alcohol
(mg per 100 mℓ
-1
)
Glucose
(mg per 100 mℓ
-1
)
Salicylate
(mg per 100 mℓ
-1
)
Isolate
35.8 400.2 0.00
Saccharomyces cerevisiae
25.2 340.8 0.00
Saccharomyces cerevisiae
40.2 385.2 0.00 -
37.2 372.8 0.00
Saccharomyces cerevisiae
30.2 382.4 0.00 -
Mean 33.72 376.40 0.00
S. D 5.99 22.20 0.00
S. E 2.68 9.93 0.00
n 5 5 5
Table 4. Comparative biochemical parameters of regularly sold palm wine and freshly tapped palm wine.
Regularly sold palm wine
Biochemical parameters
N Mean SD SEM
Al
cohol (a )
15 117.71 43.69 11.28
Glucose (a
1
)
15 15.57 19.15 4.94
Salicylate (a
0
)
15 4.53 × 10
-2
6.40 × 10
-2
1.6 × 10
-2
Regularly tapped palm wine
Biochemical parameters
N Mean SD SEM
Alcohol (a )
5 33.72 5.99 2.68
Glucose (a
1
)
5 376.40 22.20 4.94
Salicylate (a
0
)
5 0.00 0.00 0.00
When a is compared with b, (t = 4.21, p<0.05) (significant difference), when a
1
is compared with b
1
, (t = 35.16, p<0.05) (significant
difference), when a
0
is compared with b
0
, (t = 1.56, p>0.05) (No significant difference).

538 Afr. J. Food Sci.
salicylate poisoning. Further investigation is suggested to
prove this. The toxic effects of salicylate are complex.
These could be life-threatening or even lead to mortality
(Musumba et al., 2004; Lewis et al., 2006; Reingardienė
and Lažauskas, 2006; Chyka et al., 2007). Ingestion of
salicylic acid tablets is the most common cause of
salicylate poisoning (Reingardienė and Lažauska, 2006).
In a child, moderately severe poisoning is achieved by
the ingestion of 240 mg kg
-1
(Done, 1978). In adults, 150
to 300 mg kg
-1
is moderately toxic while >500 mg kg
-1
is
potentially lethal (Temple, 1981). Its overdose stimulates
the respiratory centre, inhibits citric acid cycle, stimulates
lipid metabolism and inhibits amino acid metabolism.
Clinical effects are nausea, vomiting acute renal failure,
gastrointestinal bleeding and epigastric discomfort (van
Heijst and Dijk, 1991). Symptoms of mild poisoning are
dizziness, sweating and vomiting. Severe poisoning is
characterized by respiratory alkalosis and metabolic
acidosis (Meredith and Vale, 1981, 1986).
Conclusion
The presence of salicylate in the regularly sold palm wine
as opposed to the freshly tapped is certainly a result of
adulteration of the product. To avoid salicylate poisoning
and high alcohol intake, we advocate consumption of
freshly tapped, unadulterated palm wine. Moreover, palm
wine and some other traditionally fermented drinks have
provided basic food and drink in many African countries.
It is thus a commodity with economic, social and cultural
value and hence should be maintained in its original
unadulterated form.
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