EVALUATING THE PROBIOTIC POTENTIALS OF BACTERIA ISOLATED FROM SOME LOCALLY FERMENTED NIGERIAN FOODS
Faculty
Department
Year of Publication
upload
Publication Type
Abstract
Fermented foods are known to contain active components such as probiotics and antioxidants. Probiotics are living microbes which when taken in sufficient amounts confer health benefits. Due to lactose intolerance in some individuals and the high fat content of dairy foods, other means of obtaining probiotics have been explored. The aim of this study was to evaluate the probiotic potential of some bacteria isolated from Nigerian fermented foods. Samples of fufu, ogi, tuwo, palm-wine, ogogoro, iru,
ogiri and ugba were purchased from New Benin Market in Benin City, Edo State, Nigeria. Enumeration and isolation of bacterial and lactic acid bacteria were carried out using nutrient agar and De Man, Rogosa and Sharpe agar, using pour plate technique. Cultural, morphological and biochemical tests were employed to identify the bacteria isolated. The bacterial isolates were subjected to acidic pH of 3 and bile salt concentration of 0.3%. The antibiotic susceptibility of the isolates were determined using
the disc diffusion method. The antibacterial activity of the isolates were tested against three test pathogens, Escherichia coli, Salmonella sp. and Klebsiella sp. using the agar well diffusion technique Kirby Bauer disk diffusion method. The mean heterotrophic bacterial counts of Nigerian fermented foods ranged from 5.00±0.28 (ogiri) - 8.70±0.42×107 cfu/g (iru), while the lactic acid bacterial countsranged from 0.80±0.28 (iru) – 5.00±0.42×104 cfu/g. Bacillus sp,, Citrobacter sp., Lactobacillus sp.1,
Lactobacillus fermentum2 and Streptococcus sp.2 were isolated from ogi, Bacillus subtilis3 and Streptococcus sp.1 were isolated from the ugba, Klebsiella pneumonia were isolated from fufu, Lactobacillus fermentum1 were isolated from tuwo, Bacillus subtilis1 were isolated from iru, Lactobacillus sp.2 were isolated from palm-wine while Bacillus subtilis2 were isolated from ogiri-egusi and Escherichia coli isolated from ogogoro. The result of the acid tolerance tests revealed that percentage survivability ranged from 55.60% (Streptococcus sp.1) – 200.00% (Citrobacter sp.1). Percentage survival of bacterial isolates to bile salt concentration of 0.3% ranged from 147.80% (Streptococcus sp.2) – 462.50% (Escherichia coli). The antibiotic resistance index ranged from 2 (Streptococcus sp. and Bacillus subtilis3) –8 (Escherichia coli). The antibacterial activity of the isolates ranged from 2mm-10mm with Escherichia coli and Citrobacter species having no activity against any of the test pathogens. Bacillus subtilis E2 passed all the test criteria, so it can be recommended as a potential probiotics, while Escherichia coli was suspected to be a contaminant due to observed antibiotics resistance. To avoid contaminants in fermented foods, proper hygienic measures, production
procedures, storage and cooking should be ensured.
ogiri and ugba were purchased from New Benin Market in Benin City, Edo State, Nigeria. Enumeration and isolation of bacterial and lactic acid bacteria were carried out using nutrient agar and De Man, Rogosa and Sharpe agar, using pour plate technique. Cultural, morphological and biochemical tests were employed to identify the bacteria isolated. The bacterial isolates were subjected to acidic pH of 3 and bile salt concentration of 0.3%. The antibiotic susceptibility of the isolates were determined using
the disc diffusion method. The antibacterial activity of the isolates were tested against three test pathogens, Escherichia coli, Salmonella sp. and Klebsiella sp. using the agar well diffusion technique Kirby Bauer disk diffusion method. The mean heterotrophic bacterial counts of Nigerian fermented foods ranged from 5.00±0.28 (ogiri) - 8.70±0.42×107 cfu/g (iru), while the lactic acid bacterial countsranged from 0.80±0.28 (iru) – 5.00±0.42×104 cfu/g. Bacillus sp,, Citrobacter sp., Lactobacillus sp.1,
Lactobacillus fermentum2 and Streptococcus sp.2 were isolated from ogi, Bacillus subtilis3 and Streptococcus sp.1 were isolated from the ugba, Klebsiella pneumonia were isolated from fufu, Lactobacillus fermentum1 were isolated from tuwo, Bacillus subtilis1 were isolated from iru, Lactobacillus sp.2 were isolated from palm-wine while Bacillus subtilis2 were isolated from ogiri-egusi and Escherichia coli isolated from ogogoro. The result of the acid tolerance tests revealed that percentage survivability ranged from 55.60% (Streptococcus sp.1) – 200.00% (Citrobacter sp.1). Percentage survival of bacterial isolates to bile salt concentration of 0.3% ranged from 147.80% (Streptococcus sp.2) – 462.50% (Escherichia coli). The antibiotic resistance index ranged from 2 (Streptococcus sp. and Bacillus subtilis3) –8 (Escherichia coli). The antibacterial activity of the isolates ranged from 2mm-10mm with Escherichia coli and Citrobacter species having no activity against any of the test pathogens. Bacillus subtilis E2 passed all the test criteria, so it can be recommended as a potential probiotics, while Escherichia coli was suspected to be a contaminant due to observed antibiotics resistance. To avoid contaminants in fermented foods, proper hygienic measures, production
procedures, storage and cooking should be ensured.
Supervisor(s)
co-supervisor