Papers by Wacoo Paul Alex
Journal of Agricultural Biotechnology and Sustainable Development, Sep 25, 2014
Traditional knowledge has made appreciable contributions to people's sustenance and livelihoods. ... more Traditional knowledge has made appreciable contributions to people's sustenance and livelihoods. Its contribution to science and technology is however not recorded, codified, stored or systematized to spur knowledge sharing and science and technology development. It continues to be ordinary, couched and associated with low prestige rural life. An innovation systems framework was used to study the dynamics and mechanism for product, process and organizational innovations in the cassava production systems. The research study revealed that though some traditional knowledge driven innovations may be risky to health and environment; many made a positive contribution to people's sustenance and livelihoods through production of innovative goods and services, improved livelihoods, sustenance, food safety and wholesomeness. The main argument in this study was that innovation strategies rooted in the traditional knowledge systems were socially inclusive and augurs sustainable development. The study underscored the value of creating systemic linkages useful in integrating traditional and modern knowledge systems to develop crop production systems.
Fecal Coliforms are the most important indicator of hygienic quality of water. Frequently used me... more Fecal Coliforms are the most important indicator of hygienic quality of water. Frequently used methods for detection of fecal Coliforms such as Multiple-tube fermentation technique, membrane filtration technique, and enzymatic methods are extremely time-consuming and require at least 18 hours to detect them. A rapid and very sensitive thin layer chromatography (TLC) techniques based on the detection of ortho-nitophenol a byproduct of enzymatic breakdown of ortho-Nitrophenyl-β-D-galactopyranoside by galactosidase secreted by the fecal Coliforms at 44.5OC was developed. Water (100 mL) samples spiked with fecal coliform (1 to 109 CFU) were uniformly mixed with 3.6 g of Lauryl Sulfate mixed with o-Nitrophenyl-β-D-galactopyranoside (1.0 g/L) and incubated at 44.5 oC for 2 hours. ortho-Nitrophenol was extracted from each sample with 10 mL of hexane. Aliquots of 5 µL each of sample extracts were spotted on Silica Gel and plates developed in a mobile phase composed of a mixture of Water, hexane and ethyl acetate. After the chromatography ascended to the 10 cm mark, the plates were then dried with a stream of hot air (110 oC). The dried plates were exposed to ammonia vapour to ease detection of o-nitrophenol spots. The TLC technique detected fecal Coliforms just after 4 hours of incubation with a detection limit of 1 CFU/100 mL. This method is very sensitive, specific, and can be used for rapid screening of water sources for fecal Coliforms. The method can be used as a tool for quick decision making since the regulatory standards for potable water in many countries requires less than 1 colony/100 mL.
Toxins, Jan 11, 2018
In sub-Saharan Africa, there is a high demand for affordable and accessible methods for on-site d... more In sub-Saharan Africa, there is a high demand for affordable and accessible methods for on-site detection of aflatoxins for appropriate food safety management. In this study, we validated an electrochemical immunosensor device by the on-site detection of 60 maize flour samples from six markets and 72 samples from households in Kampala. The immunosensor was successfully validated with a linear range from 0.7 ± 0.1 to 11 ± 0.3 µg/kg and limit of detection (LOD) of 0.7 µg/kg. The maize flour samples from the markets had a mean total aflatoxin concentration of 7.6 ± 2.3 µg/kg with approximately 20% of the samples higher than 10 µg/kg, which is the maximum acceptable level in East Africa. Further down the distribution chain, at the household level, approximately 45% of the total number contained total aflatoxin levels higher than the acceptable limit. The on-site detection method correlated well with the established laboratory-based HPLC and ELISA-detection methods for aflatoxin B₁ with ...
Journal of Visualized Experiments, 2016
A novel dried bacterial consortium of Lactobacillus rhamnosus yoba 2012 and Streptococcus thermop... more A novel dried bacterial consortium of Lactobacillus rhamnosus yoba 2012 and Streptococcus thermophilus C106 is cultured in 1 L of milk. This fresh starter can be used for the production of fermented milk and other fermented foods either at home or at small-scale in rural settings. For the fresh starter, 1 L of milk is pasteurized in a pan that fits into a larger pan containing water, placed on a source of heat. In this water bath, the milk is heated and incubated at 85 °C for 30 min. Thereafter, the milk is cooled down to 45 °C, transferred to a vacuum flask, inoculated with the dried bacteria and left for at least 16 hr between 30 °C and 45 °C. For the purpose of frequent home production, the fresh starter is frozen into ice cubes, which can be used for the production of small volumes of up to 2 L of fermented milk. For the purpose of small-scale production in resource-poor countries, pasteurization of up to 100 L of milk is conducted in milk cans that are placed in a large sauce pan filled with water and heated on a fire at 85 °C for 30 min, and subsequently cooled to 45 °C. Next, the 100 L batch is inoculated with the 1 L freshly prepared starter mentioned before. To assure an effective fermentation at a temperature between 30 and 45 °C, the milk can is covered with a blanket for 12 hr. For the production of non-dairy fermented foods, the fresh starter is left in a cheese cloth for 12 hr, and the drained-off whey can be subsequently used for the inoculation of a wide range of food raw materials, including vegetables and cereal-based foods.
Journal of Sensors, 2016
An electroless plated silver/cysteine sensor platform [Glass|silver|cysteine|aflatoxin B1|horsera... more An electroless plated silver/cysteine sensor platform [Glass|silver|cysteine|aflatoxin B1|horseradish peroxidase] for the Electrochemical detection of aflatoxin B1was developed and characterized. This involved four major steps: (1) an electroless deposition of silver (plating) onto a glass slide, (2) immobilization of cysteine; (3) conjugation of aflatoxin B1to cysteine groups; and (4) blocking of free cysteine groups with horseradish peroxidase (HRP). The binding of cysteine to the silver was demonstrated by the disappearance of thiol (S-H) groups at 2500 cm−1using Fourier transmittance infrared spectra (FT-IR), while the subsequent steps in the assembly of sensor platform were monitored using both FT-IR and cyclic voltammetry, respectively. The sensor platform exhibited a broadened nonsymmetrical redox couple as indicated by cyclic voltammetry. The platform was further characterized for sensitivity and limit of detection. The indirect competitive immunoassay format, whereby free a...
Journal of Applied Chemistry, 2014
Aflatoxins are toxic carcinogenic secondary metabolites produced predominantly by two fungal spec... more Aflatoxins are toxic carcinogenic secondary metabolites produced predominantly by two fungal species: Aspergillus flavus and Aspergillus parasiticus. These fungal species are contaminants of foodstuff as well as feeds and are responsible for aflatoxin contamination of these agro products. The toxicity and potency of aflatoxins make them the primary health hazard as well as responsible for losses associated with contaminations of processed foods and feeds. Determination of aflatoxins concentration in food stuff and feeds is thus very important. However, due to their low concentration in foods and feedstuff, analytical methods for detection and quantification of aflatoxins have to be specific, sensitive, and simple to carry out. Several methods including thin-layer chromatography (TLC), high-performance liquid chromatography (HPLC), mass spectroscopy, enzyme-linked immune-sorbent assay (ELISA), and electrochemical immunosensor, among others, have been described for detecting and quant...
Journal of Food Quality, 2021
Aflatoxins are endemic in Kenya. The 2004 outbreak of acute aflatoxicosis in the country was one ... more Aflatoxins are endemic in Kenya. The 2004 outbreak of acute aflatoxicosis in the country was one of the unprecedented epidemics of human aflatoxin poisoning recorded in mycotoxin history. In this study, an elaborate review was performed to synthesize Kenya’s major findings in relation to aflatoxins, their prevalence, detection, quantification, exposure assessment, prevention, and management in various matrices. Data retrieved indicate that the toxins are primarily biosynthesized by Aspergillus flavus and A. parasiticus, with the eastern part of the country reportedly more aflatoxin-prone. Aflatoxins have been reported in maize and maize products (Busaa, chan’gaa, githeri, irio, muthokoi, uji, and ugali), peanuts and its products, rice, cassava, sorghum, millet, yams, beers, dried fish, animal feeds, dairy and herbal products, and sometimes in tandem with other mycotoxins. The highest total aflatoxin concentration of 58,000 μg/kg has been reported in maize. At least 500 acute human i...
Journal of lipids, 2018
The overwhelming demand of oil and fats to meet the ever increasing needs for biofuel, cosmetics ... more The overwhelming demand of oil and fats to meet the ever increasing needs for biofuel, cosmetics production, and other industrial purposes has enhanced a number of innovations in this industry. One such innovation is the use of microorganisms as alternative sources of oil and fats. Organic solid waste that is causing a big challenge of disposal worldwide is biodegradable and can be utilized as substrate for alternative oil production. The study evaluated the potential of isolated yeast-like colonies to grow and accumulate oil by using organic solid waste as substrate. Of the 25 yeast-like colonies isolated from the soil samples collected from three different suburbs in Kampala district, Uganda, 20 were screened positive for accumulation of lipid but only 2 were oleaginous. The NHC isolate with the best oil accumulation potential of 48.8% was used in the central composite design (CCD) experiments. The CCD experimental results revealed a maximum oil yield of 61.5% from 1.25 g/L cell b...
Journal of Food Quality, 2021
Aflatoxins are endemic in Kenya. e 2004 outbreak of acute aflatoxicosis in the country was one of... more Aflatoxins are endemic in Kenya. e 2004 outbreak of acute aflatoxicosis in the country was one of the unprecedented epidemics of human aflatoxin poisoning recorded in mycotoxin history. In this study, an elaborate review was performed to synthesize Kenya's major findings in relation to aflatoxins, their prevalence, detection, quantification, exposure assessment, prevention, and management in various matrices. Data retrieved indicate that the toxins are primarily biosynthesized by Aspergillus flavus and A. parasiticus, with the eastern part of the country reportedly more aflatoxin-prone. Aflatoxins have been reported in maize and maize products (Busaa, chan'gaa, githeri, irio, muthokoi, uji, and ugali), peanuts and its products, rice, cassava, sorghum, millet, yams, beers, dried fish, animal feeds, dairy and herbal products, and sometimes in tandem with other mycotoxins. e highest total aflatoxin concentration of 58,000 μg/kg has been reported in maize. At least 500 acute human illnesses and 200 deaths due to aflatoxins have been reported. e causes and prevalence of aflatoxins have been grossly ascribed to poor agronomic practices, low education levels, and inadequate statutory regulation and sensitization. Low diet diversity has aggravated exposure to aflatoxins in Kenya because maize as a dietetic staple is aflatoxin-prone. Detection and surveillance are only barely adequate, though some exposure assessments have been conducted. ere is a need to widen diet diversity as a measure of reducing exposure due to consumption of aflatoxin-contaminated foods.
In sub-Saharan Africa, there is a high demand for affordable and accessible methods for on-site d... more In sub-Saharan Africa, there is a high demand for affordable and accessible methods for on-site detection of aflatoxins for appropriate food safety management. In this study, we validated an electrochemical immunosensor device by the on-site detection of 60 maize flour samples from six markets and 72 samples from households in Kampala. The immunosensor was successfully validated with a linear range from 0.7 ± 0.1 to 11 ± 0.3 µg/kg and limit of detection (LOD) of 0.7 µg/kg. The maize flour samples from the markets had a mean total aflatoxin concentration of 7.6 ± 2.3 µg/kg with approximately 20% of the samples higher than 10 µg/kg, which is the maximum acceptable level in East Africa. Further down the distribution chain, at the household level, approximately 45% of the total number contained total aflatoxin levels higher than the acceptable limit. The on-site detection method correlated well with the established laboratory-based HPLC and ELISA-detection methods for aflatoxin B 1 with the correlation coefficients of 0.94 and 0.98, respectively. This study shows the feasibility of a novel on-site detection method and articulates the severity of aflatoxin contamination in Uganda. Key Contribution: This paper described the validation of a novel immunosensor for the on-site detection of aflatoxins and showed that in households in Uganda, almost half of the maize flour samples contained more than 10 µg of aflatoxin per kg, which was more than the maximum acceptable level in East Africa.
A novel dried bacterial consortium of Lactobacillus rhamnosus yoba 2012 and Streptococcus thermop... more A novel dried bacterial consortium of Lactobacillus rhamnosus yoba 2012 and Streptococcus thermophilus C106 is cultured in 1 L of milk. This fresh starter can be used for the production of fermented milk and other fermented foods either at home or at small-scale in rural settings. For the fresh starter, 1 L of milk is pasteurized in a pan that fits into a larger pan containing water, placed on a source of heat. In this water bath, the
milk is heated and incubated at 85 °C for 30 min. Thereafter, the milk is cooled down to 45 °C, transferred to a vacuum flask, inoculated with the
dried bacteria and left for at least 16 hr between 30 °C and 45 °C. For the purpose of frequent home production, the fresh starter is frozen into
ice cubes, which can be used for the production of small volumes of up to 2 L of fermented milk. For the purpose of small-scale production in
resource-poor countries, pasteurization of up to 100 L of milk is conducted in milk cans that are placed in a large sauce pan filled with water and heated on a fire at 85 °C for 30 min, and subsequently cooled to 45 °C. Next, the 100 L batch is inoculated with the 1 L freshly prepared starter mentioned before. To assure an effective fermentation at a temperature between 30 and 45 °C, the milk can is covered with a blanket for 12 hr. For the production of non-dairy fermented foods, the fresh starter is left in a cheese cloth for 12 hr, and the drained-off whey can be subsequently used for the inoculation of a wide range of food raw materials, including vegetables and cereal-based foods.
An electroless plated silver/cysteine sensor platform [Glass|silver|cysteine|aflatoxin B1|horsera... more An electroless plated silver/cysteine sensor platform [Glass|silver|cysteine|aflatoxin B1|horseradish peroxidase] for the Electrochemical detection of aflatoxin B1 was developed and characterized. This involved four major steps: (1) an electroless deposition of silver (plating) onto a glass slide, (2) immobilization of cysteine; (3) conjugation of aflatoxin B1 to cysteine groups; and (4) blocking of free cysteine groups with horseradish peroxidase (HRP).The binding of cysteine to the silver was demonstrated by the disappearance of thiol (S-H) groups at 2500 cm−1 using Fourier transmittance infrared spectra (FT-IR), while the subsequent steps in the assembly of sensor platform were monitored using both FT-IR and cyclic voltammetry, respectively. The sensor platform exhibited a broadened nonsymmetrical redox couple as indicated by cyclic voltammetry. The platform was further characterized for sensitivity and limit of detection. The indirect competitive immunoassay format, whereby free and immobilized aflatoxin B1 on the sensor competed for the binding site of free anti-aflatoxin B1 antibody, was used at various concentrations of aflatoxin B1. The sensor generated differential staircase voltammogram that was inversely proportional to the concentration of aflatoxin B1 and aflatoxin B1 in the range of 0.06–1.1 ng/mL with a detection limit of 0.08 ng/mL could be detected.
The development of a field-deployable biosensor device for aflatoxin detection is an attractive e... more The development of a field-deployable biosensor device for aflatoxin detection is an attractive endeavor that should solve current bottlenecks related to the current chromatographic and spectroscopic techniques including: the requirement for highly trained operators, time consuming between analyses and obtaining of results, the requirement for labeling in some instances, and high costs of the equipment, among others. Besides, such an analytical device should: requires smaller sample volumes, release of analytical results fast, cheap, precise as well as accurate, and used at the point of need. To achieve these goals, the newly developed biosensor platform (electroless plated silver/cysteine sensor platform [Glass|silver|cysteine|aflatoxin B1|horseradish peroxidase]; Wacoo et al, [1], was functionalized into an electrochemical aflatoxin B1 biosensor device. The biosensor prototype was assembled by interfacing: (1) the sensor platform containing biorecognition element and the traducer with (2) electronic relay system made of potentiostat with PIC16F877A microcontroller, the liquid-crystal display (LCD), and the system powered by a replaceable 5 volt battery. The immunosensor prototype successfully generated a quasi-reversible redox peak characteristic of the developed sensor platform at 600 mV and a differential staircase voltammogram (DSCV) cathodic peak at 304 mV with the peak height of 5920 mV. Therefore, when this prototype is validated for aflatoxin B1 analysis, it could be used for analysis of aflatoxin B1 in food samples.
Fecal Coliforms are the most important indicator of hygienic quality of water. Frequently used me... more Fecal Coliforms are the most important indicator of hygienic quality of water. Frequently used methods for detection of fecal Coliforms such as Multiple-tube fermentation technique, membrane filtration technique, and enzymatic methods are extremely time-consuming and require at least 18 hours to detect them. A rapid and very sensitive thin layer chromatography (TLC) techniques based on the detection of ortho-nitophenol a byproduct of enzymatic breakdown of ortho-Nitrophenyl-β-D-galactopyranoside by galactosidase secreted by the fecal Coliforms at 44.5OC was developed. Water (100 mL) samples spiked with fecal coliform (1 to 109 CFU) were uniformly mixed with 3.6 g of Lauryl Sulfate mixed with o-Nitrophenyl-β-D-galactopyranoside (1.0 g/L) and incubated at 44.5 oC for 2 hours. ortho-Nitrophenol was extracted from each sample with 10 mL of hexane. Aliquots of 5 µL each of sample extracts were spotted on Silica Gel and plates developed in a mobile phase composed of a mixture of Water, hexane and ethyl acetate. After the chromatography ascended to the 10 cm mark, the plates were then dried with a stream of hot air (110 oC). The dried plates were exposed to ammonia vapour to ease detection of o-nitrophenol spots. The TLC technique detected fecal Coliforms just after 4 hours of incubation with a detection limit of 1 CFU/100 mL. This method is very sensitive, specific, and can be used for rapid screening of water sources for fecal Coliforms. The method can be used as a tool for quick decision making since the regulatory standards for potable water in many countries requires less than 1 colony/100 mL.
Aflatoxins are toxic carcinogenic secondary metabolites produced predominantly by two fungal spec... more Aflatoxins are toxic carcinogenic secondary metabolites produced predominantly by two fungal species: Aspergillus flavus and
Aspergillus parasiticus. These fungal species are contaminants of foodstuff as well as feeds and are responsible for aflatoxin
contamination of these agro products. The toxicity and potency of aflatoxins make them the primary health hazard as well as
responsible for losses associated with contaminations of processed foods and feeds. Determination of aflatoxins concentration in
food stuff and feeds is thus very important. However, due to their low concentration in foods and feedstuff, analytical methods for
detection and quantification of aflatoxins have to be specific, sensitive, and simple to carry out. Several methods including thin-layer
chromatography (TLC), high-performance liquid chromatography (HPLC), mass spectroscopy, enzyme-linked immune-sorbent
assay (ELISA), and electrochemical immunosensor, among others, have been described for detecting and quantifying aflatoxins
in foods. Each of these methods has advantages and limitations in aflatoxins analysis.This review critically examines each of the
methods used for detection of aflatoxins in foodstuff, highlighting the advantages and limitations of each method. Finally, a way
forward for overcoming such obstacles is suggested.
Traditional knowledge has made appreciable contributions to people’s sustenance and livelihoods. ... more Traditional knowledge has made appreciable contributions to people’s sustenance and livelihoods. Its contribution to science and technology is however not recorded, codified, stored or systematized to spur knowledge sharing and science and technology development. It continues to be ordinary, couched and associated with low prestige rural life. An innovation systems framework was used to study the dynamics and mechanism for product, process and organizational innovations in the cassava production systems. The research study revealed that though some traditional knowledge driven innovations may be risky to health and environment; many made a positive contribution to people’s sustenance and livelihoods through production of innovative goods and services, improved livelihoods, sustenance, food safety and wholesomeness. The main argument in this study was that innovation strategies rooted in the traditional knowledge systems were socially inclusive and augurs sustainable development. The study underscored the value of creating systemic linkages useful in integrating traditional and modern knowledge systems to develop crop production systems.
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Papers by Wacoo Paul Alex
milk is heated and incubated at 85 °C for 30 min. Thereafter, the milk is cooled down to 45 °C, transferred to a vacuum flask, inoculated with the
dried bacteria and left for at least 16 hr between 30 °C and 45 °C. For the purpose of frequent home production, the fresh starter is frozen into
ice cubes, which can be used for the production of small volumes of up to 2 L of fermented milk. For the purpose of small-scale production in
resource-poor countries, pasteurization of up to 100 L of milk is conducted in milk cans that are placed in a large sauce pan filled with water and heated on a fire at 85 °C for 30 min, and subsequently cooled to 45 °C. Next, the 100 L batch is inoculated with the 1 L freshly prepared starter mentioned before. To assure an effective fermentation at a temperature between 30 and 45 °C, the milk can is covered with a blanket for 12 hr. For the production of non-dairy fermented foods, the fresh starter is left in a cheese cloth for 12 hr, and the drained-off whey can be subsequently used for the inoculation of a wide range of food raw materials, including vegetables and cereal-based foods.
Aspergillus parasiticus. These fungal species are contaminants of foodstuff as well as feeds and are responsible for aflatoxin
contamination of these agro products. The toxicity and potency of aflatoxins make them the primary health hazard as well as
responsible for losses associated with contaminations of processed foods and feeds. Determination of aflatoxins concentration in
food stuff and feeds is thus very important. However, due to their low concentration in foods and feedstuff, analytical methods for
detection and quantification of aflatoxins have to be specific, sensitive, and simple to carry out. Several methods including thin-layer
chromatography (TLC), high-performance liquid chromatography (HPLC), mass spectroscopy, enzyme-linked immune-sorbent
assay (ELISA), and electrochemical immunosensor, among others, have been described for detecting and quantifying aflatoxins
in foods. Each of these methods has advantages and limitations in aflatoxins analysis.This review critically examines each of the
methods used for detection of aflatoxins in foodstuff, highlighting the advantages and limitations of each method. Finally, a way
forward for overcoming such obstacles is suggested.
milk is heated and incubated at 85 °C for 30 min. Thereafter, the milk is cooled down to 45 °C, transferred to a vacuum flask, inoculated with the
dried bacteria and left for at least 16 hr between 30 °C and 45 °C. For the purpose of frequent home production, the fresh starter is frozen into
ice cubes, which can be used for the production of small volumes of up to 2 L of fermented milk. For the purpose of small-scale production in
resource-poor countries, pasteurization of up to 100 L of milk is conducted in milk cans that are placed in a large sauce pan filled with water and heated on a fire at 85 °C for 30 min, and subsequently cooled to 45 °C. Next, the 100 L batch is inoculated with the 1 L freshly prepared starter mentioned before. To assure an effective fermentation at a temperature between 30 and 45 °C, the milk can is covered with a blanket for 12 hr. For the production of non-dairy fermented foods, the fresh starter is left in a cheese cloth for 12 hr, and the drained-off whey can be subsequently used for the inoculation of a wide range of food raw materials, including vegetables and cereal-based foods.
Aspergillus parasiticus. These fungal species are contaminants of foodstuff as well as feeds and are responsible for aflatoxin
contamination of these agro products. The toxicity and potency of aflatoxins make them the primary health hazard as well as
responsible for losses associated with contaminations of processed foods and feeds. Determination of aflatoxins concentration in
food stuff and feeds is thus very important. However, due to their low concentration in foods and feedstuff, analytical methods for
detection and quantification of aflatoxins have to be specific, sensitive, and simple to carry out. Several methods including thin-layer
chromatography (TLC), high-performance liquid chromatography (HPLC), mass spectroscopy, enzyme-linked immune-sorbent
assay (ELISA), and electrochemical immunosensor, among others, have been described for detecting and quantifying aflatoxins
in foods. Each of these methods has advantages and limitations in aflatoxins analysis.This review critically examines each of the
methods used for detection of aflatoxins in foodstuff, highlighting the advantages and limitations of each method. Finally, a way
forward for overcoming such obstacles is suggested.