In Nigeria most foods are preserved by adding salt. The efficacy of this and some other chemical ... more In Nigeria most foods are preserved by adding salt. The efficacy of this and some other chemical preservatives in improving the storage quality of fermented locust beans was the focus of this study. Samples of fermented locust beans were separately treated with table salt (10% w/w), brine (10 and 20% solution), vinegar (4 and 6%) and lactic acid (10 and 20%). After treatment, all the samples were stored at ambient temperature and periodically analysed for sensory and microbiological properties. Samples treated with dry salt became slippery, changed in color and developed bad odor within 1, 4 and 14 days respectively. Except for the softening observed, no significant (p < 0.5) change occurred with the color and odor of the other samples during storage. A total of 29 bacterial and 6 fungal isolates were obtained. The dominant bacteria were members of the genera Bacillus, Staphylococcus, Pseudomonas, Micrococcus, Citrobacter, Microbacterium, Enterobacter, Leuconostoc, Arthrobacter, and Corynebacterium while Saccharomyces cerevisae, Aspergillus niger and other Aspergillus spp., dominated the fungal population. Other fungi were Rhizopus stolonifer, Alternaria alternata, and Candida albicans. The microbial load and diversity reduced significantly (p < 0.5) after treatment and during storage. Among the bacterial isolates, Bacillus cereus, B. pumilus, B. lentus, B. licheniformis, Staphylococcus epidermidis, S. saprophyticus Citrobacter freundii, Arthrobacter ureafaciens, Corynebacterium poinsetiae, Micrococcus denitrificans and Microbacterium sp. were inhibited by lactic acid, vinegar and brine with diameter zone of inhibition ranging from 11.0 to 24.0mm; 15.0 to 20.5mm and 12.5 to 22.5 mm respectively. This study has shown that lactic acid, vinegar and brine have some preservative effects on fermented locust beans and can therefore be used to prolong its shelf life.
Fermented Soymilk (FSM), a protein rich beverage is highly prone to microbial contamination. Its ... more Fermented Soymilk (FSM), a protein rich beverage is highly prone to microbial contamination. Its preservation is therefore key to its availability and safety. Soymilk was prepared by aqueous extraction of soybeans and allowed to ferment spontaneously. Samples of FSM were treated with leaf essential oil of Hoslundia opposita (LEOHO) at 5% and 10% (v/v) and stored at ambient temperature. The organoleptic, pH and microbiological qualities of the samples were evaluated periodically during storage. The protein content was significantly (p
local cheese has been reported to be a high risk food in Nigeria due to the possible transmission... more local cheese has been reported to be a high risk food in Nigeria due to the possible transmission of numerous spoilage and pathogenic bacteria. This study therefore investigated not only the spoilage and pathogenic bacteria associated with local cheese sold within Ilorin metropolis but also microbiological food safety of the food through the use of Syzygium cumini oil as a preservative. Samples of wara were collected from selected seller across the metropolis and analysed for the presence of different bacterial species using spread plate method on appropriate selective growth media. All the bacterial isolates were identified using biochemical test. Invitro therapeutic efficacy of S.cumini oil aginst foodborne isolates was carried out using Kirby-Bauer method. The most six prevalent bacterial isolates were Bacillus subtilis, Proteus vulgaris, Escherichia coli, Listeria monocytogene, Salmonella typhimurium and Staphylococcus aureus were isolated from the wara. Hydrodistilled leaves of Syzygium cumini yielded 0.32% (v/w) of essential oil. Examination of the oil by GC and GC/MS uncovered that the greater part of the oil was comprised by sesquiterpenes. Other outstanding constituents were Cis-Beta-Farnesene (1.40%), Beta-Ocimene (2.11%), Betabisabolol (1.48%), Beta-Ocimene (2.11%), and D-Limonene (2.89%). Antibacterial action was measured base on the zone of inhibition and minimum inhibitory concentration. The oil repressed the development of Proteus vulgaris at 25% concentration, Escherichia coli at 12.5% concentration, Listeria monocytogene at 6.25% concentration, Salmonella typhimurium at 12.5% concentration and Staphylococcus aureusat 6.25% concentration while no action was recorded against B. subtilis. Highest activity, represented by diameter of zone of clearance around the loaded wells was recorded for Staphylococcus aureus. Accordingly, the oil can be an elective method for averting spoilage in stored wara in this manner expanding its time span of edibility.
Antibacterial Activities of some Antidiarrheal Herbal Concoctions Locally Prepared in Ilorin, Nigeria on Fecal Isolates
Antibacterial activity of herbal concoctions commonly used to treat diarrhea in Ilorin, Nigeria w... more Antibacterial activity of herbal concoctions commonly used to treat diarrhea in Ilorin, Nigeria was determined against fecal isolates. Aqueous extracts of different combinations of the herbs used were prepared by soaking for eighteen days. Samples were taken daily for four days and weekly thereafter and used to challenge bacteria isolated from human feces. The efficacy of the herbal extracts was compared with a standard antibiotic, streptomycin. Most of the isolates were inhibited by the 48 hours herbal extracts. Inhibition zone ranged from 11.4 to 20.0 mm and 4.6 to 19.8 mm for the adult men and women extracts; and 9.6 to 32.0 mm for the children extract. The minimum inhibitory concentration ranged from 25 to 100%. Apart from Enterococcus feacalis and Staphylococcus aureus, susceptibility to the herbal extracts compared favorably with reference drug, streptomycin with percentage inhibition reaching 100, 120, 150 and 160 respectively for Proteus vulgaris, Salmonella enteritica, Esch...
Nigerian locally produced cheese from milk, commonly known as wara is highly nutritious and highl... more Nigerian locally produced cheese from milk, commonly known as wara is highly nutritious and highly prone to attack by spoilage and pathogenic microorganisms. Moist heat treatment and salting alone are the common methods used for processing. This study assessed the efficacy of these local processing methods in preserving the physicochemical properties and microbiological quality of wara. Samples were purchased from open markets in Ilorin; processed by boiling in water and with addition of salt; and stored at room temperature (28±2oC) to mimic the local method. The samples were observed at 24 hrs interval for a period of 96 hrs, for changes in pH, color, odor and texture. Microbiological analysis was done following standard methods. The pH of most of the samples increased while the color, odor and texture deteriorated within 48 hrs of storage. The cheese samples were preserved most by boiling with salt. Many spoilage and pathogenic microorganisms were isolated. The bacterial isolates ...
Leaves and fruits (500g each) of Ocimum basilicum that were separately hydrodistilled, yielded 0.... more Leaves and fruits (500g each) of Ocimum basilicum that were separately hydrodistilled, yielded 0.4 and 0.5% (v/w) of the oils respectively. Analyses of the oils using GC and GC-MS showed that, bulk of the oils were constituted by oxygenated monoterpenes. The principal constituents of the leaf and fruit oils were; linalool (61.7 and 62.9%), 1,8-cineole (17.2 and 18.7%), borneol (8.5 and 6.4%), eugenol (5.7 and 5.4%) and α-caryophyllene (4.3 and 4.0%). With the predominance of linalool in the oils, they are of linalool chemotypes. The antibacterial activities of the oils were evaluated on ten clinical bacterial isolates using disc diffusion method. The oils were found to inhibit three Gram-positive and three Gram-negative bacteria. The bacteria inhibited were Bacillus megaterium, Bacillus cereus, Streptococcus pyogenes, Escherichia coli, Proteus mirabilis and Klebsiella pneumonia. Bacillus megaterium had the highest susceptibility with minimum inhibitory concentration (MIC) of 2.5 mg ml -1 . Bacillus cereus, Streptococcus pyogenes, Serratia marcescens and Pseudomonas aeruginosa showed resistance to the oils.
This study investigated the amylase activity of a yellow pigmented bacterium isolated from cassav... more This study investigated the amylase activity of a yellow pigmented bacterium isolated from cassava wastes obtained from a dumpsite near a gari processing factory in Ibadan, Nigeria. Isolate was grown in nutrient broth containing 1% starch and then centrifuged at 5,000 rpm. Amylase activity was assayed using the DNSA method for the detection of reducing sugar. Best enzyme activity was recorded at 30ºC and pH 7.5. The amylase was found to be stable after exposure to temperatures between 20 and 40ºC and pH 6.0 to 9.0, outside which there was a decline in activity. The ability of the isolate to produce amylase explains its colonization of a cassava waste dumpsite. Conditions of activity and stability also agree with the growth condition of the isolate.
Corn cob is a major component of agricultural and domestic waste in many parts of the world. It i... more Corn cob is a major component of agricultural and domestic waste in many parts of the world. It is composed mainly of cellulose which can be converted to energy in form of bioethanol as an efficient and effective means of waste management. Production of cellulolytic enzymes were induced in the fungi Aspergillus niger and Penicillium decumbens by growing them in mineral salt medium containing alkali pre-treated and untreated corn cobs. The cellulases were characterized and partially purified. Alkali pre-treated corn cobs were hydrolysed with the partially purified cellulases and the product of hydrolysis was fermented using the yeast saccharomyces cerevisae to ethanol. Cellulases of A. niger produced higher endoglucanase and exoglucanase activity (0.1698 IU ml-1 and 0.0461 FPU ml-1) compared to that produced by P. decumbens (0.1111 IU ml-1 and 0.153 FPU ml-1). Alkali pre-treated corn cob hydrolysed by cellulases of A. niger yielded 7.63 mg ml-1 sugar which produced 2.67 % (v/v) ethan...
The demand for lactic acid is steadily increasing due to the desire of its bioproduction over che... more The demand for lactic acid is steadily increasing due to the desire of its bioproduction over chemical synthesis. The associated cost, however, is a significant hurdle. This study reports lactic acid fermentation by Lactobacillus casei ATCC334 from cassava peel. It investigates the effect of unhydrolysed cassava peels, acidic, alkali hydrolysates; fermenting pH; substrate concentration; nitrogen source concentration; duration; and inoculum size. An attempt at a cheaper purification and recovery protocol relative to those currently in use was similarly performed. Acidic hydrolysate yielded 10.53%, unhydrolysed substrate gave 4.80% with alkali hydrolysate yielding 4.75%. The highest LA yield was obtained at pH 6.0, 2.0% v/v inoculum size, 25% w/v substrate concentration, 5% nitrogen source concentration. A post-optimisation combination yielded 18.3% LA suggesting that one-factor-at-a-time may be unsuitable for optimisation studies involving cassava peel and L. casei ATCC334. FTIR spec...
In Nigeria most foods are preserved by adding salt. The efficacy of this and some other chemical ... more In Nigeria most foods are preserved by adding salt. The efficacy of this and some other chemical preservatives in improving the storage quality of fermented locust beans was the focus of this study. Samples of fermented locust beans were separately treated with table salt (10% w/w), brine (10 and 20% solution), vinegar (4 and 6%) and lactic acid (10 and 20%). After treatment, all the samples were stored at ambient temperature and periodically analysed for sensory and microbiological properties. Samples treated with dry salt became slippery, changed in color and developed bad odor within 1, 4 and 14 days respectively. Except for the softening observed, no significant (p < 0.5) change occurred with the color and odor of the other samples during storage. A total of 29 bacterial and 6 fungal isolates were obtained. The dominant bacteria were members of the genera Bacillus, Staphylococcus, Pseudomonas, Micrococcus, Citrobacter, Microbacterium, Enterobacter, Leuconostoc, Arthrobacter, and Corynebacterium while Saccharomyces cerevisae, Aspergillus niger and other Aspergillus spp., dominated the fungal population. Other fungi were Rhizopus stolonifer, Alternaria alternata, and Candida albicans. The microbial load and diversity reduced significantly (p < 0.5) after treatment and during storage. Among the bacterial isolates, Bacillus cereus, B. pumilus, B. lentus, B. licheniformis, Staphylococcus epidermidis, S. saprophyticus Citrobacter freundii, Arthrobacter ureafaciens, Corynebacterium poinsetiae, Micrococcus denitrificans and Microbacterium sp. were inhibited by lactic acid, vinegar and brine with diameter zone of inhibition ranging from 11.0 to 24.0mm; 15.0 to 20.5mm and 12.5 to 22.5 mm respectively. This study has shown that lactic acid, vinegar and brine have some preservative effects on fermented locust beans and can therefore be used to prolong its shelf life.
Fermented Soymilk (FSM), a protein rich beverage is highly prone to microbial contamination. Its ... more Fermented Soymilk (FSM), a protein rich beverage is highly prone to microbial contamination. Its preservation is therefore key to its availability and safety. Soymilk was prepared by aqueous extraction of soybeans and allowed to ferment spontaneously. Samples of FSM were treated with leaf essential oil of Hoslundia opposita (LEOHO) at 5% and 10% (v/v) and stored at ambient temperature. The organoleptic, pH and microbiological qualities of the samples were evaluated periodically during storage. The protein content was significantly (p
local cheese has been reported to be a high risk food in Nigeria due to the possible transmission... more local cheese has been reported to be a high risk food in Nigeria due to the possible transmission of numerous spoilage and pathogenic bacteria. This study therefore investigated not only the spoilage and pathogenic bacteria associated with local cheese sold within Ilorin metropolis but also microbiological food safety of the food through the use of Syzygium cumini oil as a preservative. Samples of wara were collected from selected seller across the metropolis and analysed for the presence of different bacterial species using spread plate method on appropriate selective growth media. All the bacterial isolates were identified using biochemical test. Invitro therapeutic efficacy of S.cumini oil aginst foodborne isolates was carried out using Kirby-Bauer method. The most six prevalent bacterial isolates were Bacillus subtilis, Proteus vulgaris, Escherichia coli, Listeria monocytogene, Salmonella typhimurium and Staphylococcus aureus were isolated from the wara. Hydrodistilled leaves of Syzygium cumini yielded 0.32% (v/w) of essential oil. Examination of the oil by GC and GC/MS uncovered that the greater part of the oil was comprised by sesquiterpenes. Other outstanding constituents were Cis-Beta-Farnesene (1.40%), Beta-Ocimene (2.11%), Betabisabolol (1.48%), Beta-Ocimene (2.11%), and D-Limonene (2.89%). Antibacterial action was measured base on the zone of inhibition and minimum inhibitory concentration. The oil repressed the development of Proteus vulgaris at 25% concentration, Escherichia coli at 12.5% concentration, Listeria monocytogene at 6.25% concentration, Salmonella typhimurium at 12.5% concentration and Staphylococcus aureusat 6.25% concentration while no action was recorded against B. subtilis. Highest activity, represented by diameter of zone of clearance around the loaded wells was recorded for Staphylococcus aureus. Accordingly, the oil can be an elective method for averting spoilage in stored wara in this manner expanding its time span of edibility.
Antibacterial Activities of some Antidiarrheal Herbal Concoctions Locally Prepared in Ilorin, Nigeria on Fecal Isolates
Antibacterial activity of herbal concoctions commonly used to treat diarrhea in Ilorin, Nigeria w... more Antibacterial activity of herbal concoctions commonly used to treat diarrhea in Ilorin, Nigeria was determined against fecal isolates. Aqueous extracts of different combinations of the herbs used were prepared by soaking for eighteen days. Samples were taken daily for four days and weekly thereafter and used to challenge bacteria isolated from human feces. The efficacy of the herbal extracts was compared with a standard antibiotic, streptomycin. Most of the isolates were inhibited by the 48 hours herbal extracts. Inhibition zone ranged from 11.4 to 20.0 mm and 4.6 to 19.8 mm for the adult men and women extracts; and 9.6 to 32.0 mm for the children extract. The minimum inhibitory concentration ranged from 25 to 100%. Apart from Enterococcus feacalis and Staphylococcus aureus, susceptibility to the herbal extracts compared favorably with reference drug, streptomycin with percentage inhibition reaching 100, 120, 150 and 160 respectively for Proteus vulgaris, Salmonella enteritica, Esch...
Nigerian locally produced cheese from milk, commonly known as wara is highly nutritious and highl... more Nigerian locally produced cheese from milk, commonly known as wara is highly nutritious and highly prone to attack by spoilage and pathogenic microorganisms. Moist heat treatment and salting alone are the common methods used for processing. This study assessed the efficacy of these local processing methods in preserving the physicochemical properties and microbiological quality of wara. Samples were purchased from open markets in Ilorin; processed by boiling in water and with addition of salt; and stored at room temperature (28±2oC) to mimic the local method. The samples were observed at 24 hrs interval for a period of 96 hrs, for changes in pH, color, odor and texture. Microbiological analysis was done following standard methods. The pH of most of the samples increased while the color, odor and texture deteriorated within 48 hrs of storage. The cheese samples were preserved most by boiling with salt. Many spoilage and pathogenic microorganisms were isolated. The bacterial isolates ...
Leaves and fruits (500g each) of Ocimum basilicum that were separately hydrodistilled, yielded 0.... more Leaves and fruits (500g each) of Ocimum basilicum that were separately hydrodistilled, yielded 0.4 and 0.5% (v/w) of the oils respectively. Analyses of the oils using GC and GC-MS showed that, bulk of the oils were constituted by oxygenated monoterpenes. The principal constituents of the leaf and fruit oils were; linalool (61.7 and 62.9%), 1,8-cineole (17.2 and 18.7%), borneol (8.5 and 6.4%), eugenol (5.7 and 5.4%) and α-caryophyllene (4.3 and 4.0%). With the predominance of linalool in the oils, they are of linalool chemotypes. The antibacterial activities of the oils were evaluated on ten clinical bacterial isolates using disc diffusion method. The oils were found to inhibit three Gram-positive and three Gram-negative bacteria. The bacteria inhibited were Bacillus megaterium, Bacillus cereus, Streptococcus pyogenes, Escherichia coli, Proteus mirabilis and Klebsiella pneumonia. Bacillus megaterium had the highest susceptibility with minimum inhibitory concentration (MIC) of 2.5 mg ml -1 . Bacillus cereus, Streptococcus pyogenes, Serratia marcescens and Pseudomonas aeruginosa showed resistance to the oils.
This study investigated the amylase activity of a yellow pigmented bacterium isolated from cassav... more This study investigated the amylase activity of a yellow pigmented bacterium isolated from cassava wastes obtained from a dumpsite near a gari processing factory in Ibadan, Nigeria. Isolate was grown in nutrient broth containing 1% starch and then centrifuged at 5,000 rpm. Amylase activity was assayed using the DNSA method for the detection of reducing sugar. Best enzyme activity was recorded at 30ºC and pH 7.5. The amylase was found to be stable after exposure to temperatures between 20 and 40ºC and pH 6.0 to 9.0, outside which there was a decline in activity. The ability of the isolate to produce amylase explains its colonization of a cassava waste dumpsite. Conditions of activity and stability also agree with the growth condition of the isolate.
Corn cob is a major component of agricultural and domestic waste in many parts of the world. It i... more Corn cob is a major component of agricultural and domestic waste in many parts of the world. It is composed mainly of cellulose which can be converted to energy in form of bioethanol as an efficient and effective means of waste management. Production of cellulolytic enzymes were induced in the fungi Aspergillus niger and Penicillium decumbens by growing them in mineral salt medium containing alkali pre-treated and untreated corn cobs. The cellulases were characterized and partially purified. Alkali pre-treated corn cobs were hydrolysed with the partially purified cellulases and the product of hydrolysis was fermented using the yeast saccharomyces cerevisae to ethanol. Cellulases of A. niger produced higher endoglucanase and exoglucanase activity (0.1698 IU ml-1 and 0.0461 FPU ml-1) compared to that produced by P. decumbens (0.1111 IU ml-1 and 0.153 FPU ml-1). Alkali pre-treated corn cob hydrolysed by cellulases of A. niger yielded 7.63 mg ml-1 sugar which produced 2.67 % (v/v) ethan...
The demand for lactic acid is steadily increasing due to the desire of its bioproduction over che... more The demand for lactic acid is steadily increasing due to the desire of its bioproduction over chemical synthesis. The associated cost, however, is a significant hurdle. This study reports lactic acid fermentation by Lactobacillus casei ATCC334 from cassava peel. It investigates the effect of unhydrolysed cassava peels, acidic, alkali hydrolysates; fermenting pH; substrate concentration; nitrogen source concentration; duration; and inoculum size. An attempt at a cheaper purification and recovery protocol relative to those currently in use was similarly performed. Acidic hydrolysate yielded 10.53%, unhydrolysed substrate gave 4.80% with alkali hydrolysate yielding 4.75%. The highest LA yield was obtained at pH 6.0, 2.0% v/v inoculum size, 25% w/v substrate concentration, 5% nitrogen source concentration. A post-optimisation combination yielded 18.3% LA suggesting that one-factor-at-a-time may be unsuitable for optimisation studies involving cassava peel and L. casei ATCC334. FTIR spec...
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