Microbiological quality of raw edible vegetables sampled from cafeterias at Universiti Sains Malaysia, Kubang Kerian, Kelantan
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Date
2013
Authors
Dianne, Kua Vee May
Journal Title
Journal ISSN
Volume Title
Publisher
Pusat Pengajian Sains Kesihatan, Universiti Sains Malaysia
Abstract
Raw fruits and vegetables have been known to serve as vehicles of human diseases
and food borne outbreaks have increased in recent years. Raw vegetables
contaminated with pathogenic bacteria may lead to health hazard as there is no
treatment that can be relied upon for decontamination of the vegetables. A study was
conducted to screen and identify the bacterial pathogens present in selected raw
vegetables sold in the cafeterias in USM Health Campus. A total of 30 samples from
six commonly consumed raw vegetables viz., cucumber, winged bean, lettuce, wild
cosmos, pennywort leaves and water dropwort were analyzed. Samples were
randomly collected over a period of two months. Fifty grams (50g) from each sample
were taken for microbiological analysis. The presence and identification of
pathogenic bacteria viz., E.coli, Bacillus cereus, Staphylococcus aureus, Salmonella
and total coliforms was determined based on the "Australian Microbiological
Examination of Food", (1993) and the analysis was conducted in triplicates.
Compliance to the microbiological quality (CFU/g) of raw vegetables is based on the
"Microbiology Guidelines for Ready to Eat Food" MOH Malaysia ( 1985). The
results showed that the total coliforms were presence in all vegetables samples
(~1,000 CFU/g, unsatisfactory). A total of 6 (20%) samples (1 cucumber, 1
pennywort, 3 water dropwort and 1 wild cosmos) showed presence of pathogenic
bacteria namely E.coli and Salmonella. However, lettuce and winged bean did not show presence of any of the pathogenic bacteria. E. coli was detected ( 3-1 00 CFU/g ,
marginal) in 25% of the pennywort, 22.2% water dropwort (3x 103 -5x 1 oJ CFU/g,
unsatisfactory), and 50% wild cosmos samples (1x103 CFU/g, unsatisfactory).
Meanwhile, Salmonella was detected in 12.5% of the cucumber and 11.1% water
dropwort samples. However, the presence of Bacillus cereus and Staphylococcus
aureus were not detected in any of the raw vegetables sampled. Our findings
revealed that all vegetables samples showed presence of total coliforms, and some
with E.coli and Salmonella, exceeding the safe level described by "Microbiology
Guidelines for Ready to Eat Food" MOH Malaysia (1985), and this can be construed
that the contaminated vegetables may pose considerable hazards on human health.
Furthermore, further identification has led to the detection of an enteric serovar
weltevreden which has been implicated with several cases of food borne illnesses
(Bangtrakulnonth, 2004). However, no pathogenic E.coli was isolated in this study.
Thus, further study should be carried out to determine the source of contamination so
that measures can be taken to improve the microbiological quality of raw vegetables
sold in Health Campus, USM.
Description
Keywords
raw fruits