Browsing by Author "Onyimba I. A."

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Application of extracts of Henna (Lawsonia inamis) leaves as a counter stain
(African Journal of Microbiology Research, 2011-10-09) Chukwu O. O. C.; Odu C. E.; Chukwu D. I.; Hafiz N.; Chidozie V. N.; Onyimba I. A.
Aqueous (cold and hot) and ethanol extracts solutions of the Henna plant (Lawsonia inamis) leaves was adapted for the first time as a counter stain in Gram staining reaction. Different extracts of L. inamis leaves were formulated into various staining solutions of different concentrations and modified with hydrogen peroxide, ferric chloride, potassium alum and potassium permanganate. These staining solutions were used to stain both known Gram positive and Gram negative bacterial isolates using Gram staining technique. The experimental Henna plant extracts solutions were used with usual counter stains (neutral red, safranine and dilute carbol fuchsin) as positive controls. Phytochemical screening of the extracts revealed the presence of tannin (hennatonic acid or Lawsone) and saponin. The aqueous extracts of the Henna plant (cold and hot) oxidized with potassium permanganate (pH 7.00 to 7.16) gave a better staining reaction with Gram negative bacteria, while the ethanol extract oxidized with potassium permanganate (pH 6.55) had no staining reaction with Gram negative bacteria. Hence the aqueous Henna leaves extracts (cold or hot) when oxidized with potassium permanganate can be a substitute to the usual counter stains used in Gram staining procedure. The results of staining ability of the various henna leaves extracts solutions are discussed.
Carrot (Daucus carrota), Garlic (Allium sativum) and Ginger (Zingiber officinale) Extracts as Bacteria Selective Agents in Culture Media
(African Journal of Microbiology Research, 2011-12-23) Chukwu O. O. C; Odu C. E.; Chukwu I. D.; Chidozie V. N.; Onyimba I. A.; Bala Z.
Extracts of carrot, garlic and ginger as selective agents in basal bacteriological media were carried out on Staphylococcus aureus ATCC 15313, Listeria monocytogenes ATCC 2522, Escherichia coli ATCC 25922 and Pseudomonas aeruginosa ATCC 27853 using a standard method. Ethanolic extracts, aqueous cold and hot extracts of the experimental plant products were made at the concentration of 200 mg/ml (2 g/10 ml). The ethanolic extracts inhibited the growth of all the test bacterial isolates. The cold aqueous extracts of garlic had inhibitory effects on the S. aureus and L. monocytogenes bacterial isolates but selectively allowed the growth of E. coli. The hot aqueous extract of ginger had no effect on any of the test bacteria. The hot garlic extract selectively allowed the growth of L. monocytogenes and E. coli. Phytochemical analysis of the carrots, garlic and ginger contained saponnin, resins, alkaloids, flavonoids, steroids and terpenes in varied proportions. We assume these products may have influenced the actions of the extracts on the test organisms. The results of this preliminary study suggest that aqueous extracts of carrots, garlic and ginger when incorporated in appropriate concentrations can serve as alternative selective agents in bacteriological culture media for bacterial isolation from highly contaminated biological specimens or separation of mixed cultures of bacteria in the laboratory.
Microbiological Quality of Pre-cut Fruits on Sale in Retail Outlets in Nigeria
(African Journal of Agricultural Research, 2010-09-04) Chukwu C. O. C.; Chukwu I. D.; Onyimba I. A.; Umoh E. G.; Olarubofin F.; Olabode A. O.
Microbiological quality of pre-cut fruits sold in retail outlets in Kano metropolis in Nigeria was evaluated. One hundred and fifty pre-cut fruit samples comprising pineapples (50), paw-paw (50) and watermelon (50) at the point of stand retail outlets were tested by standard microbiological methods to determine bacterial and parasite contamination. Out of these, 136 (90.67%) were contaminated with bacteria. Parasites were absent in all samples. The general distribution of the bacterial contaminations were; Escherichia coli 69 (46.00%), Staphylococcus aureus 29 (19.33%), Salmonella species 13 (8.67%), Proteus species 18 (12.00%), Enterobacter aerogenes 3 (2.00%), Klebsiella pneumoniae 2 (1.33%) and Pseudomonas aeruginosa 2 (1.33%). Among the 50 pineapple cuts - E. coli 26, S. aureus 6, Salmonella species 7, Proteus species 9, P. aeruginosa 2; the 50 watermelon had E. coli 22, S. aureus 13, Salmonella species 3, Proteus species 5, E. aerogenes 2 and K. species 2. From 50 paw-paw cuts E. coli 21, S. aureus 10, Salmonella species 3, Proteus species 4 and E. aerogenes 1 were isolated. These findings demonstrate that microbiological quality of pre-cut fruits sampled, suggest that the risk of foodborne illness from pre-cut fruits is high. There is a need to enforce good food hygiene practices to avoid contamination of pre-cut fruits.