ABSTRACT
This research work was done to investigate the presence of Escherichia coli and Bacillus species in Dambu-nama samples obtained from different supermarkets in Abuja and their susceptibility to chitosan and antibiotics. Four samples of Dambu-nama were purchased and assayed microbiologically using pour plate isolation method on nutrient agar, eosin methylene blue and bacillus cereus agar. The total viable bacterial counts recorded range from (0.38±0.5× 106 cfu/g - 2.45± 0.5×108 cfu/g). The microorganisms isolated include Bacillus subtilis, Enterobacter aerogenes, Salmonella spp, Enterobacter faecalis and Bacillus spp. The least occuring bacteria were Salmonella spp (75%) and Enterobacter faecalis (75%) while the most occuring bacteria were Enterobacter aerogenes (100%) and Bacillus spp (100%). The highest resistance index for Gram-positive bacteria was shown by Bacillus subtilis (0.5) while the lowest resistance index was shown by Bacillus spp (0.0). For Gram-negative bacteria, Salmonella spp and Enterobacter aerogenes shown a resistance index of ( 0.2 and 0.3) respectively. The proximate composition of Dambu-nama, higher percentage of moisture content (8.83±0.25%, 8.81±0.03%), ash (4.41±0.17%, 5.55±0.03%), fat (15.48±0.13%, 15.71±0.07%) and protein (62.75±0.25%, 64.21±0.03%) were recorded in chicken samples while higher nitrogen free extract (22.25±0.56%, 20.53±0.03%)was recorded in beef samples. Using chitosan as an antimicrobial agent, the concentration used were 5.80mg/ml, 2.90mg/ml, 1.45mg/ml and 0.75mg/ml. No effect were recorded on Enterobacter aerogenes at all concentrations (0.00±0.00mm), while Enterobacter faecalis and Bacillus spp were more inhibited by the various concentrations of chitosan (3.47±0.29mm, 3.33±0.18mm, 3.27±0.07mm, 3.67±1.05mm) (2.80±0.31mm, 3.33±0.55mm, 3.13±0.44mm, 3.00±0.58mm) respectively. Dambu-nama though highly nutritious,has been shown to be heavily contaminated with microorganisms which may be detrimental to human health.
