The Prevalence and Growth Potential of Some Salmonella Species in "Kitfo" and Effect of "Kitfo" Preparation Processes on the Test Organisms
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Date
1997-05
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Addis Ababa University
Abstract
In an attempt to assess the microbial load and the prevalence of salmonellae in "kitfo", a total of 50
raw or "Tire kitfo" samples were collected from ten food establishments (hotels, restaurant and bars)
from different areas of Addis Ababa. The microbial load in "tire kitfo" samples collected from all
sources was markedly high. The highest average loads of aerobic mesophilic bacteria (8.33
Log(CFUlg», coliforms (6.77 Log(CFUlg», staphylococci (7.29 Log(CFUlg», lactic acid bacteria
(5.37 Log(CFU/g», molds and yeasts (5.96 Log(CFUlg», and aerobic spores (5.67 Log(CFUlg»
were encountered in "kitfo" from three hotels and one bar. On the other hand, the lowest average
loads of aerobic mesophilic bacteria (7.30 Log(CFU/g», coliforms (4.51 Log(CFU/g»,
staphylococci (6.18 Log(CFU/g», lactic acid bacteria (4.10 Log(CFU/g», molds and yeasts (4.06
Log(CFUlg», and aerobic spores (3.71 Log(CFU/g» were found from one restaurant and two
hotels. Variation within samples in counts of coliforms, staphylococci, lactic acid bacteria, molds
and yeasts, and aerobic spores was significant in all or most establishments (CV> 10%). However,
counts of staphylococci and lactic acid bacteria did not show marked variations among hotels,
restaurant and bars. Variation within samples in the count of aerobic mesophilic bacteria in most
food establishments was not significant (CV < 10%). The microbial load of slightly cooked "kitfo"
("Iebleb kitfo") was found to be high, though it was less than that of raw or "tire kitfo". Variation in
the counts of aerobic mesophilic bacteria, staphylococci and lactic acid bacteria in "lebleb kitfo"
atllJHg ten establisluIleIlts was liul slgiiincalit (CV ~ 10%), while thaI of coliforms, molds and yeasts,
and aerobic spores was significant (CV> 10%). No microorganisms have been detected from "tibs
kitfo", except very few aerobic spores. From the study of the prevalence of Salmonella in "kitfo"
twenty one positive samples were obtained from the 50 samples collected from the above hotels,
restaurant and bars. Among these positive samples of Salmonella, the highest number of positive
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positive samples (one) was from Hotel G. No Salmonella was isolated from "kitfo" of Hotel D, E
and Restaurant A. No Salmonella was encountered in "lebleb" and "tibs kitfo" samples. Of the
three selective enrichment broths, i.e. Selenite Broth, Thetrathionate Broth, and Rappaport- Vassiliadis
Medium used for enriching the growth of Salmonella species, RVB was found to be superior. Of the
four plating media, i.e., Salmonella-Shigella (SS)agar, MacConkey agar, Brilliant Green agar (BG) and
Xylose Lysine Desoxycholate (XLD) medium, BG was found out to be superior in supporting the
growth of salmonellae encountered in this work. The microbial load of swabs from raw beef was
relatively low when compared to that of "kitfo". The loads of aerobic mesophilic bacteria, coliforms,
staphylococci, lactic acid bacteria, molds & yeasts and aerobic spores were found to be 5.07
Log(CFU/cm'), 2.34 Log(CFU/cm'), 3.14 Log(CFU/cm'), 2.63 Log(CFU/cm'), 2.54 Log(CFUlcm'),
and 2.60 Log(CFU/cm'), respectively. When assessing the growth potential of Salmonella species in
"kitfo", they were found to grow weI!. They grew to the level of 7.0 Log(CFU/g) within 12h of
incubation.
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