Microbiological Profile and Safety of Some Street vended Foods in Addis Ababa
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Date
1999-06
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Addis Ababa University
Abstract
Microbiological profiles and safety of street-vended food collected from vendors in Addis
Ababa, Ethiopia were determined in 1998 and 1999. The 150 samples of foods investigated
consisted of sambllssa (legume-based), cooked and sauced macaroni, lentil sandwich, kitfo
(raw minced and spiced meat dish) and egg sandwich. All samples of kitfo and egg
sandwich were held at temperatures that permit bacterial growth (15.5-24S C) and (15.5-
34S C), respectively. Most samples of the other food products were stored at temperature
range of 15.5-34S C. In general, sambllssa had low counts of aerobic mesophilic bacteria
and staphylococci. Aerobic bacterial spores, yeasts, members of Enterobacteriaceae,
colifonns and Bacillus cerellS were isolated rarely in sambllssa. Highest aerobic mesophilic
counts (> 108 cfb/g) were recorded in egg sandwich. The other food products contained
counts as high as 107 cfu/g. Presumptive Bacillus cereus attained greatest population level
in macaroni samples (> 10' cfu/g). In other dishes it had counts> 104 cfuig. Majority of the
samples which were positive tor aerobic bacterial spores, coliforms, Enterobacteriaceae,
staphylococci and yeasts contained >104
, 10', 105
, 105
, and 104 cfuig, respectively. In the
street foods considered in this study, moulds were either detected rarely or not at all.
Variations in counts among the samples of the respective street foods were obvious (CV
10%).A total of 1552 bacterial isolates were screened from foods obtained from street vendors
and were characterized into various genera and bacterial groups. Gram-positive organisms
predominated (76.9%) along with Staphylococcus and Micrococcus species comprising
22.8% and 15% of aerobic microflora, respectively. From Gram-negative organisms,
members of a family Enterobacteriaceae (14.5%) were frequently encountered. Salmonella
was recovered from samples of egg sandwich and kitfo and macaroni yielded Shigella.
Challenge studies showed that the test strains, Salmonella typhimul'illlll, Shigella flexneri
and Staphylococcus aureus grew in egg sandwich, kitfo and macaroni to markedly high
levels. The faulty handling and serving operations, poor sanitation of the vending sites,
time-temperature abuse during holding, addition of raw products either to cooked or
uncooked dishes, the use of unclean multipurpose cloth and water of dubious quality
(reused water) were deemed potentially hazardous. Thus, education of both vendors and
consumers in basic principles of hygiene is an urgent issue by concerned bodies.
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Biology