microbial quality of food snacks and drinking water in ... - PJAR

Pakistan J. Agric. Res. Vol 22 No. 3-4, 2009.
MICROBIAL QUALITY OF FOOD SNACKS AND DRINKING WATER
IN ISLAMABAD SCHOOLS AND COLLEGES
Ambreen Akhtar Saddozai, Samina Khalil and Tabassum Hameed*
ABSTRACT: The study was undertaken to determine the microbiological quality
of various food items available in different schools and colleges of Islamabad.
For sampling of water and food items, ten different schools and colleges were
selected . These samples were analyzed for Total plate count (TPC), Total coliform,
Fecal coliform, E.coli. Yeasts and Moulds. The data revealed that out of 30 water
and 10 food samples, 12 samples of water and only 3 samples of food were found
within range of permissible limits while the remaining were highly contaminated
and unfit for human consumption. This study has socio-economic benefit monitoring
the health standards of population especially the young generation.
Key Words: Microbial; Contamination; Food Items; Water; Health; Pakistan.
INTRODUCTION
Food is the most fundamental need of
human being. It is only nutritive when it
is pure, fresh and free from hazardous
matter such as pathogenic bacteria and
sub-standard food colors. Infected or contaminated
food endangers health and impairs
quality of life. According to WHO (1994)
more than 80% human diseases are due
to contaminated food and water. Pakistan
is struggling hard to provide its citizens
with basic amenities but clean drinking
water is not available to great number of
people mainly because of rising level of pollution
in the environment, poor un-keeping
of water supply lines and faulty drainage
system (Farrukh et al., 2004). In Pakistan
more than 140 million people today,
lack access to adequate supply of safe water
for household use. Contaminated food
and polluted water causes diseases like dysentery,
hepatitis, cholera, typhoid, fever
and bacteriosis (IDRC, 1988 and Thomas
et al., 1986).
Many developing regions suffer from
either chronic shortages of freshwater or
the pollution of readily accessible water
resources (Lehloesa and Muyima, 2000).
According to a recent UNICEF report, about
800 million people in Asia and Africa are
living without access to safe drinking water.
Consequently, this has caused many
144
people to suffer from various diseases
(Tanwir and Shan, 2003).
Water polluted with feces is often contaminated
with a group of bacteria belonging
to family enterobacteriaceae, so called
because of their normal habitat is the intestinal
tract of man and other animals.
Medically this family is further divided into
two groups (a) organisms occurring exclusively
as intestinal pathogens e.g., Salmonella
and Shigella (b) organisms occurring
primarily as intestinal commensals, e.g.
coliform and Proteus. E.coli is a typical organism
of the intestinal tract and is
present in large numbers in the feces of
man and other animals. Water is a basic
constituent of almost all the food items, so
infected or contaminated water endangers
health, impairs quality of life and is proved
to be a serious hazard in Pakistan (Khan,
1986). Several researchers have reported
different pollutants in drinking water
sampled from different regions of Pakistan.
Ahmed and Saleem (1983) analyzed drinking
water of NWFP for chemical pollutants.
Bacteriological quality of drinking water
from rural areas of Pakistan was determined
by Wadud et al. (1992). Pathogenic
microorganisms have been reported in
water supplies of different areas of
Peshawar where 50% water samples were
highly contaminated and unfit for human
consumption (Khan et al., 2000). Water
*Grain Quality Testing Lab., National Agricultural Research Centre, Islamabad, Pakistan.

quality in different areas of Punjab including
selected parts of Rawalpindi and
Islamabad has been studied for nitrate
contamination and nitrate level were found
to exceed the Canadian standard for drinking
water (Ashraf et al., 1986). Pakistan
Council of Research in Water Resources
carried out a survey to determine quality
of drinking water in Rawalpindi and
Islamabad. Minerals, heavy metals and
microbiological contamination were analyzed
and it was reported that water was fit
for consumption with respect to physiochemical
and aesthetic water qualities.
However, 75% samples in Islamabad were
found unsafe for human consumption due
to bacterial contamination, based on total
coliform quantification (PCRWR, 2001).
According to FAO (1992) involvement
of E.coli in several cases of food poisoning
suggests that this organism, rather than
fecal coliform group, should be used as an
indicator of sanitary quality. Microbiological
standards for drinking water in most
developed countries rely on the detection
of total coliform and E.coli as markers for
enteric organism (Karatz et al., 1999). The
main objective of the reported study was to
determine the microbiological quality of
various food items available in tuck shops
of different schools and colleges of
Islamabad.
AMBREEN AKHTAR SADDOZAI ET AL.
145
MATERIALS AND METHODS
Samples were collected from seven different
schools and three colleges. Drinking
water samples were collected in sterile
bottles for microbial analysis from taps,
general water cooler and canteen water
cooler, while food sample was obtained from
school/college canteens in sterile containers
under aseptic conditions. Three water
and one food snack samples (samosa) were
collected from each school and college.
Total plate count, coliform, E.coli, yeast and
moulds were determined by the method
described in FAO (1992). According to this
method food (samosa) was homogenized
with Butter field’s phosphate buffer (pH 7.2).
Ten fold serial dilution of the food were prepared.
One milliliter volumes were transferred
to petri dishes with plate count agar
and mixed with medium in triplicate. After
48 h incubation at 35 0 C, colonies formed
on the surface and in the medium were
counted. The total count was calculated
from the mean count of triplicate of petri
dishes, taking the dilution into consideration.
Similarly yeast growth was checked
on plate count agar amended with chloramphenicol
@ 40 ppm. Petri plates were incubated
at 25°C. Potato dextrose agar was used
to detect moulds. Coliform and E.coli in food
items were determined by Most Probable
Number (MPN) method (FAO, 1992). According
to this method the density of viable organisms
in a sample is estimated. The
sample is diluted in such a manner that a
more dilute sample results in fewer positive
tubes, which are indicated by the presence
of gas or microbial growth. Serial dilutions
of 10 -1 , 10 -2 , 10 -3 of the sample were
taken with three tubes in a series. The
number of positive and negative tubes was
compared with the MPN index with 95%
confidence limits for various combinations
of positive results. Water analysis was carried
out by multiple tube method. According
to this method, 5ml of water sample
being tested is added to double strength and
10 ml to single strength of MacConkey
broth. After 48h incubation at 35 0 C each
tube which received one or more viable organism
in the inoculums showed growth
and the most probable number of organisms
in the original sample was estimated from
the tubes giving positive reaction. Most
probable number (MPN) coliforms per 100
ml of water sample were calculated from
the relevant MPN table.
RESULTS AND DISCUSSION
As per WHO (1994) standards the
maximum permissible limits in cooked
food of Aerobic plate count (APC) is 10,000
cfu g -1 , coliform

MICROBIAL QUALITY OF FOOD SNACKS AND DRINKING WATER
Table 1. Microbiological analysis of drinking water of schools and colleges
F.G. F.G. F.G. F.G. F.G. F.G. F.G. F.G. Islamabad Islamabad
College Girls Higher Junior Model Model Model Model Model Model
for Boys Sec. Sec. Model School School School School College College
G-6/3, School School for Public G-6/4, G-7/3, G-9/4, F-8/3, for Boys for Boys
Islamabad No.12 Boys No. School Islamabad Islamabad Islamabad Islamabad G-10/4, G-11/1,
Parameters NIH, 15, NIH, for Girls Islamabad Islamabad
Islamabad Islamabad G-6/2,
Islamabad
Tap TPC 76500 560 333 Nil Nil 20 250 25 23 50
water Coliform 23 Nil Nil Nil Nil 35 1800 Nil Nil Nil
Fecal 23 Nil Nil Nil Nil 25 1800 Nil Nil Nil
Coliform
E.coli Nil Nil Nil Nil Nil 25 35 Nil Nil Nil
General TPC 75 747 245 30 1370000 50 Nil 45 30 10
water Coliform Nil 15 Nil Nil 1800 13 Nil Nil Nil Nil
cooler Fecal Nil 3.6 Nil Nil 1800 6 Nil Nil Nil Nil
Coliform
E.coli Nil 3.6 Nil Nil 1800 6 Nil Nil Nil Nil
Canteen TPC 85 675 18 20 123000 90 1800 85 90 95
water Coliform 23 20 Nil Nil 1800 13 1800 Nil Nil Nil
cooler Fecal 9.1 9 Nil Nil 1800 13 225 Nil Nil Nil
Coliform
E.coli Nil 23 Nil Nil 1800 10 25 Nil Nil Nil
WHO permissible limits for water: Total Plate Count (cfu100ml -1 )=

AMBREEN AKHTAR SADDOZAI ET AL.
analysis (Table 2) are presented.
TPC, total coliform, E.coli and fecal coliform
In tap water sample collected from while general water cooler and food samples
F. G. College for Boys, G-6/3, Islamabad, were fit for consumption. All water samples
TPC, coliform, and fecal coliform were of F-8/3, G-10/4 and G-11/1 Colleges for
higher than the permissible limits while boys were within permissible limit. TPC,
in general water and canteen water cooler total coliform, E.coli, fecal coliform and yeast
samples TPC, coliform, fecal coliform, E.coli were higher in food samples of F.G. Model
were within permissible limits except School, F-8/3, Islamabad. Whereas, food
coliform in canteen water cooler sample. sample of Islamabad Model College for Boys,
In food sample collected from canteen, all G-10/4, Islamabad was contaminated with
the parameters were within permissible coliform, E.coli, fecal coliform and yeast.
limit. TPC of Tap water collected from F. G. Food sample collected from Islamabad Model
Girls Secondary School, NIH, Islamabad had College for Boys, G-11/1, Islamabad was
higher bacterial count while other counts highly polluted with coliform, E.coli and fecal
coliform, while yeast and mould were
were within range. In general, water and
canteen water cooler samples TPC, absent.
Coliform, fecal coliform and E.coli were Overall TPC was found higher in water
samples from five out of ten schools and
found to be higher than the permissible
limit. Although food sample contained low colleges. E.coli was detected in four out of
bacterial count, yeast and mould were also ten and fecal coliform five out of ten schools
absent but E.coli was detected and coliform and colleges mostly in water cooler
level was also high in this sample. So this samples. Higher contamination in water
sample was unfit for human consumption. cooler was probably due to unhygienic
Bacteriological analysis of tap and general
water cooler samples collected from glass hanged with the cooler is used by the
method for dispensing water e.g. plastic
F.G. Higher Secondary School, NIH, children repeatedly to take out water from
Islamabad showed high level of total plate the container instead of dispensing water
count, food sample was also contaminated through the cooler tap. It is also possible
with E.coli and highly polluted with coliform that children handle coolers with unwashed
bacteria. All the samples collected from F.G. hands. In food sample overall TPC was high
Junior Model School for Girls, G-6/2, in three out of ten, coliform and fecal
Islamabad were fit for consumption because
their total plate count, coliform and out of ten school and college samples.
coliform in six out of ten and E.coli in four
E.coli were within permissible range. In Several studies have been conducted
food sample, E.coli was absent, total plate on the microbial quality of different snack
count and coliform was within range. From preparations sold by the street food vendors
F.G. Boys Model School, G-6/4, Islamabad in various Asian countries. Chakravarthy
general water and canteen water cooler (1994) reported that microbial quality of the
samples were highly contaminated ( TPC, snack food sold by the street food vendors
total coliform were much higher and E.coli in Calcutta was not satisfactory. Detailed
was also present). Although E.coli was absent
in food sample it was highly contami-
standard plate counts of fermented food
analyses of food samples showed that the
nated with yeast and TPC.
products were high as compared to other
Total plate count was low in all water varieties of samples. E.coli was detected in
samples received from F.G. Model Boys 55% of the samples. Almost all the snacks
School, G-7/3, Islamabad but coliform and samples showed the presence of yeast and
E.coli were present in these samples. Food mold in minute quantities. Hema et al.
samples also contained E.coli and coliform. (1994) reported that microbial quality in
Tap water and canteen water cooler eight commonly consumed street foods including
raw food, fried items, hot and cooled
samples from F.G. Model School, G-9/4,
Islamabad were highly contaminated with foods and sweets had high microbial count
147

Table 2. Microbiological analysis of food items of schools and colleges
MICROBIAL QUALITY OF FOOD SNACKS AND DRINKING WATER
F.G. F.G. F.G. F.G. F.G. F.G. F.G. F.G. Islamabad Islamabad
College Girls Higher Junior Model Model Model Model Model Model
for Boys Sec. Sec. Model School School School School College College
G-6/3, School School for Public G-6/4, G-7/3, G-9/4, F-8/3, for Boys for Boys
Islamabad No.12, Boys No. School Islamabad Islamabad Islamabad Islamabad G-10/4, G-11/1,
Parameters NIH, 15, NIH, for Girls Islamabad Islamabad
Islamabad Islamabad G-6/2,
Islamabad
Canteen TPC 8800 9150 8300 2000 1400000 3000 2000 13500 12000 195000
Coliform Nil 15 460 9 7.2 40 9.2 210 240 75
Feacal Coliform Nil 15 93 Nil Nil 20 Nil Nil Nil 75
E.coli Nil 9 93 Nil Nil 20 35 Nil Nil 21
Yeast Nil Nil 2 Nil 15 3 Nil 10 15 Nil
Mould Nil Nil Nil Nil Nil Nil Nil Nil Nil Nil
WHO permissible limits for water: Total Plate Count (cfu 100ml -1 )=

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