Advances in Microbiology, 2012, 2, 340-344 Published Online September 2012 (
Portage of Bacteria Responsible of Foodborne Illness
in Scholarly Canteens (Republic of Benin)
Honoré Sourou Bankolé1,2, Tossou Jacques Dougnon1, Patrick Aléodjrodo Edorh3,4,
Tamègnon Victorien Dougnon1,4*, Magloire Legonou2, Jean Robert Klotoé1, Frédéric Loko1,2
1Polytechnic School of Abomey-Calavi, Research Laboratory in Applied Biology,
University of Abomey-Calavi, Cotonou, Benin
2Laboratory of Food Microbiology, Ministry of Health, Cotonou, Benin
3Faculty of Science and Technology, Department of Biochemistry and Cellular Biology,
University of Abomey-Calavi (UAC), Cotonou, Benin
4Interfaculty Center of Formation and Research in Environment for the Sustainable Development,
Laboratory of Toxicology and Environmental Health, University of Abomey-Calavi (UAC), Cotonou, Benin
Email: *
Received June 17, 2012; revised July 17, 2012; accepted July 26, 2012
This study has determined the portage of bacteria responsible for foodborne illness in the school canteen staff. 336
samples taken on the nose, mouth and hands were collected. Microbiological analyses were realized and several patho-
genic bacterial strains were isolated from the vendors: Staphylococcus aureus (26/122), sulphite-reducing clostridia
(14/122) and Escherichia coli (10/122). The food vendors in th e school canteen may be the vectors of germs that cause
food poisoning among young students.
Keywords: Portage; Bacteria; Food; Escherichia coli; Disease
1. Introduction
Foodborne diseases are, by the world, a major public
health problem. Although most often manifested by di-
arrhea with an estimated three million deaths a year in
children under five years of age, they have other serious
consequences such as kidney and liver failure, brain dis-
orders and neurological disorders and death [1,2].
According to WHO, almost one third of people in de-
veloped countries have an infection caused by foods. In
less developed countries, diarrheal diseases transmitted
through water and foods are major causes of morbidity
and mortality. They cause about 2.2 million deaths per
year especially in children [3].
In Benin, the number of cases of diarrheal diseases is
estimated at 309.944 with 331 deaths per year [4].
Deeply concerned by this situation, the 53rd World
Health Assembly adopted a resolution in May 2000 to
develop a global strategy to reduce the burden of food-
borne illness. Estimates of the overall number of epi-
sodes of foodborne illness are helpful for allocating re-
sources and prioritizing interventions. However, arriving
at these estimates is challenging because food may be-
come contaminated by many agents (a variety of bacteria,
viruses, parasites, and chemicals), transmission can occur
by nonfood mechanisms (e.g., contact with animals or
consumption of contaminated water), the proportion of
disease transmitted by food differs by pathogen and by
host factors (age and immunity), and only a small pro-
portion of illnesses are confirmed by laboratory testing
and reported to public health agencies [5].
Laboratory-based surveillance provides crucial infor-
mation for assessing foodborne disease trends. However,
because only a small proportion of illnesses are diag-
nosed and reported, periodic assessments of total epi-
sodes of illness are also needed [5]. Several countries
have conducted prospective population-based or cross-
sectional studies to sup plement surveillance and estimate
the overall number of foodborne illnesses [6]. In 2007,
the World Health Organization launched an initiative to
estimate the global burd en of foodborne diseases [7].
Most often, when cases of foodborne illness are re-
ported, only consumed foods are involved. The catering
staff which is the more in contact with food than others is
not usually investigated [8].
This observation justifies the present study entitled
“Portage of bacteria responsible of foodborne illness in
restaurants and school canteens”. It aims to determine the
*Corresponding a uthor.
opyright © 2012 SciRes. AiM
involvement of catering staff in food contamination.
2. Materials and Methods
2.1. Material
Biological material was composed of 336 samples ob-
tained by swabbing the nostrils, mouth and hands. Petri
dishes, swabs, hemolysis tubes, tubes, autoclaves, mi-
croscopes, refrigerators, lyophilized rabbit plasma, hy-
drogen peroxide, Kovacs reagent, hard oxidase, hydro-
chloric acid, gentian violet, fuchsin, lugol, Eosin Me-
thylene Blue agar, Chapman, peptone water buffered
agar, Hektoen, etc. have been used among others.
2.2. Methods
A cross-sectional study was conducted from November
2011 to June 2012. Samples were collected from nine
primary schools and three colleges randomly selected in
the 8th, 9th and 13th districts of Cotonou.
The study population was composed of 112 women in
canteens of primary schools and colleges. Nasal swabs,
mouth and hands were performed by swabbing. Ethical
approval has been received and only volunteers were
included in the study. All women underwent a medical
examination and only those who were visibly in good
health (no flu, cough) were allowed to be taken.
For nasal swabs, we left swab from its package, tilt the
patient’s head slightly back, inserted the swab into the
nostril, rotated it and print the swab in a tube containing
0.5 ml buffered peptone water in compliance with aseptic
About mouth swabs, the swab must be introduced into
the mouth of the patient. After rubbing teeth and tongue,
print the swab into a tube containing 0.5 ml buffered
peptone water.
About hands samples, we left the swab from its pack-
age, moisten it with sterile distilled water and printed it
into a tube containing 0.5 ml buffered peptone water.
All samples were transported to the laboratory in a
cooler at 4˚C. Microbiological analyzes were performed
on five days:
2.3. First day
2.3.1. F re s h State
Two drops of each of the resulting suspensions were de-
posited on a slide and covered with a coverslip. The
preparation thus obtained was observed under an optical
microscope with ×40 objective.
2.3.2. Colored Sta te
A smear was made from each suspension obtained, Gram
stained and observed microscopically at the immersion
2.3.3. Culture
The culture media were selected and seeded based on the
results of microscopic observation. The culture media
were incubated seeded according to culture condition of
suspected bacteria.
2.3.4. Pre-Enrichment for the Isolation of Salmonella
and Shigella
The suspensions obtained in peptone water were incu-
bated in an oven at 37˚C for 18 hours.
2.4. Second Day
2.4.1. Re ading
All culture media seeded the previous day were reviewed.
The colonies on selective agar media were counted. Mi-
croscopic observation of control was performed on each
culture medium.
2.4.2. Identification
The isolated bacteria were identified based on biochemi-
cal characteristics obtained through the use of the API 20
E and some biochemical tests: looking for catalase, cy-
tochrome oxidase research and research of free staphy-
locoagulase. These tests were performed following the
methodolog y adopted by [9].
2.4.3. Enrichment of Salmonella and Shigella
A volume of 0.5 ml of the culture pre-enrichment was
introduced in 4 ml of Rappaport broth. The whole was
incubated at 37˚C for 24 hours.
2.5. Day Three
2.5.1. Reading Galleries
Reading the API 20 E was conducted in accordance with
the methodology adopted by [9].
2.5.2. Isolation of Salmonella and Shigella
SS and Hektoen agars were inoculated from the enrich-
ment broth.
2.6. Day Four
Api 20 E galleries were inoculated from SS and Hektoen
agar with bacterial colonies.
2.7. Fifth Day
It was devoted to reading galleries and identification of a
possible presence of bacteria.
Statistical Analyses
The prevalence of germs found was calculated. Microsoft
Excel 2010 and XL Stat 2011 were used as software.
Copyright © 2012 SciRes. AiM
3. Results
3.1. Point of Bacterial Strains Isolated during the
About bacterial strains isolated during this study, the
results are on Figure 1. On manipulated samples, 122
bacterial strains were isolated and identified. Gram-posi-
tive cocci are leading with 47.54% followed by 29.51%
with enterobacteria.
Specifically, among the enterobacteriaceae, Klebsiella
pneumonia e is the most isolated (38. 89%) while the only
non-enterobacteriaceae isolated microorganism is Pseu-
domonas aeruginosa. Among the Gram-positive cocci,
the most isolated is Staphylococcus aureus (44.83%).
Other bacteria most frequently isolated are sulphite-re-
ducing clostridia (Figure 2).
3.2. Point of Bacterial Strains Isolated from the
Mouths of Vendors
About the distribution of bacterial strains isolated from
the mouths of vendors, the results are as shown in Figure
3. 33 bacterial strains were isolated and identified. Gram-
positive cocci are leading with 54.55% followed by
30.30%. of Enterobacteriacea e.
Figure 1. Number of bacterial strains isolated during this
Figure 2. Point of isolated bacterial species.
3.3. Point of Bacterial Strains Isolated from the
Hands of Vendors
About the distribution of bacterial strains isolated from
the hands of vendors, the results are presented in Figure
4. 37 bacterial strains were isolated and identified. En-
terobacteriaceae are leading with 45.95% followed by
24.32% with non-Enterobacteriaceae.
3.4. Point of Bacterial Strains Isolated from the
Nose of Vendors
Relative to the nose of the vendors, the results are pre-
sented in Figure 5. 52 bacterial strains were isolated and
identified. Gram-positive cocci are leading with 64.70%
followed by 17.65% with enterobacteria.
4. Discussion
This study contribute to the determination of the in-
volvement of catering staff in schools and colleges about
food contamination. Control of all aspects of quality and
food security is possible only if the operator is trained
and aware. Most vendors were educated. [10] made the
same remar k in Ghana.
The results of microbiological analyzes revealed the
Figure 3. Number of bacterial strains isolated from the
mouths of vendors.
Figure 4. Number of bacterial strains isolated from the
hands of vendors.
Copyright © 2012 SciRes. AiM
Figure 5. Number of bacterial strains isolated from the nose
of vendors.
presence of microorganisms involved in food poisoning
(Staphylococcus aureus, Escherichia coli and sulphite-
reducing clostridia); of spoilage microorganisms (Pseu-
domonas aeruginosa) and microorganisms from testify-
ing faecal contamination (Klebsiella pneumoniae, Citro-
bacter freundii, E. cloacae, P. mirabis, Providencia rett-
geri, Acinetobacter spp and streptococcus D). A study in
USA showed the same conclusions [11]. It has been in-
vestigated an outbreak in which a food handler, food
specimen, and three ill patrons were culture positive for
the same toxin-producing strain of Staphylococcus aureus
[11]. In the hands of vendors, the predominant microor-
ganism is Klebsiella pneumoniae. The presence of this
organism is soil-borne or fecal [12]. This raises the prob-
lem of compliance with the rules of hygiene by vendors
in Cotonou.
[13] reported that the role of hand-range transmission
of bacteria of fecal origin is demonstrated. This could be
explained by the lack of regular monitoring and aware-
ness of women.
The species Staphyloccoccus aureus were isolated in
18% of samples from the nose of the vendors. Although
the nasal cavity is a reservoir of this organism and that
30% of adults harbor this organism permanently, 50%
intermittently, the immaturity of about 15% of the ven-
dors induced that the risk of contamination could be high
[9]. Indeed, from the nose, the germ can spread to the
skin, hands and the environment. A survey conducted by
[14] showed that the main sources of microorganisms in
food are animal and feces [15]. In addition, Staphylo-
coccus aureus causes food-poisoning by the production
of one or more heat-stable extracellular toxins, which are
wholly responsible for the symptoms of the disease.
Foods most often incriminated in staphylococcal food-
borne disease include cooked meat, fish, poultry, bakery
foods (especially those with cream or custard fillings),
dairy produce, fruit, vegetables, and salads [16]. Methods
of food handling by vendors from preparation to the sale
do not guarantee the elimination of contamination and
microbial growth potential.
[17] showed that Staphylococcus aureus and Bacillus
cereus were often highlighted in food samples. Given the
fact that the spread of staphylococci in the environment
is possible from the nasal cavity of healthy carriers and
patients [14], we can assess the risks to students, food
consumers manipulated by these women.
Foods favor the growth of staphylococci and toxin
production are protein-rich products and products with a
pH close to neutral [18]. The majority of vendors han-
dling food are favorable to the growth of staphylococci.
Under these conditions, considering that 20 minutes is
enough for one generation [18], if the food is already
prepared at 7 o’clock in the morning and put on sale at
10 a.m, a microorganism that would contaminate the
food immediately after preparation due to poor hygiene
practice, would have had time to multiply and give ac-
cording to the formula:
Xn = Xo · 2n
Xn = 1 × 29 bacte r ia.
1 × 29 bacteria is equivalent to 512 bacteria so about 5,
102 bacteria. As shown, a sneeze could propel billions of
microorganisms in the environment, the probability of
having 106 to 1010 microorganisms per gram of food is
great, which proves that children in schools are every day
at risk of food poisoning linked to the status of porting
Following this study, were isolated and identified in
the food vendors in school canteens bacterial strains of
food poisoning, Staphylococcus aureus, Escherichia coli
and sulphite-reducing clostridia; of food spoilage bacte-
ria (Pseudomonas aeruginosa) and bacteria indicating
fecal contamination, Klebsiella pneumoniae, Citrobacter
freundii, Enterobacter cloacae, Proteus mirabis, Provi-
dencia rettgeri, Acinetobacter spp and streptococcus D.
This situation poses not on ly a problem of hygienic qual-
ity of food sold b y the women but also a potential risk of
foodborne illness among students.
5. Acknowledgements
We thank all the staff of the National Laboratory of
Health Ministry/Benin who works ev ery da y for the well-
being of peopl e .
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