Abstract:
The presence of aerobic spore forming bacteria and the problems linked to their presence in
these processed, local foods and drinks have not been studied and documented in Jimma town.
Therefore, the aim of this research was to assess the prevalence of aerobic spore forming
bacteria in selected commercial and local food samples and determining the associated risk
factors. A total of 50 samples of Keribo, Row milk,powderd milk, Wheat flour and Honey (10
samples each)were collected from five different sites in Jimma town (Kochi, Ajip, Bishishe,
Merkato and Bochobore) and their mean aerobic spore count were compared from site to site
and among the five items. After aerobic spore count, the colonies were further purified and a
total of 60 aerobic spore forming bacterial isolates (12 isolates from ten samples of each food
item) were characterized using conventional morphological, biochemical and physiological
tests. Six tentative identities of aerobic spore forming bacteria were detected using the methods
described by Bergy’s manual and ABIS. B. coagulans (41.7%), B. subtilis (33.3%), B. cereus
(25%) dominated Keribo samples while B, cereus & B, subtilis (33,3%, each), B, coagulans
(16.7%), B, megaterium(16.7%) were among the frequently isolates species from Row milk.
Bacillus subtilis (50%) dominated in Powdered milk. while B. cereus, B. coagulans, and B.
subtilis were equally detected (25% each) in honey samples. Likewise, Bacillus subtilis (50%)
was frequently identified from wheat flour. Sensitivity of the isolates towards six galleries of
antibiotics indicated that, all the detected Bacillus strains were resistant to Ampicillin but
showed similarity in their sensitivity to ciprofloxacilin, Clindomycin, Gentamycin and
vancomycin except B.coagulans and B.cereus which resisted Kanamycin and Vancomycin,
respectively. Almost all the strains exhibit multi drug resistance (showed resistance to two or
more Antibiotics).A total of 6 MDR patterns was observed in B. subtilis, followed by 4 MDR (B.
megaterium, and B. cereus), 3 MDR (B. coagulans) and 2 MDR (B. pumilus). The highest MDR
patter recorded was resistance to Ampicillin, Ciprofloxacin, Clindomycin, Gentamycin,
Kanamycin, and vancomycin. The detection of the six Bacillus strains in the five food items and
the observed high antibiotic resistance patterns calls for regular inspection for safety of these
foods and drinks.
