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Open Access October 12, 2025

Assessment of Handling Practices and Awareness of Aflatoxin Contamination in Spices among Micro and Small-Scale Processors in Tanzania

Abstract Frequent consumption of aflatoxins-contaminated spices has been linked to serious adverse health effects among consumers. The likelihood of exposure to these toxins is influenced by the level of public awareness. Controlling aflatoxins contamination throughout the food chain is critical for public health. This study aimed to assess the handling practices and awareness of aflatoxin contamination [...] Read more.
Frequent consumption of aflatoxins-contaminated spices has been linked to serious adverse health effects among consumers. The likelihood of exposure to these toxins is influenced by the level of public awareness. Controlling aflatoxins contamination throughout the food chain is critical for public health. This study aimed to assess the handling practices and awareness of aflatoxin contamination among micro- and small-scale spice processors. A total of 60 processors from 4 districts of two regions of Tanzania were interviewed. The results showed that while 56.7% of interviewed processors were aware of aflatoxin contamination in spices primarily through training (38.3%) and mass media (30%). However, there were still misconceptions regarding the causes and effects of aflatoxins to human health. It was observed that, poor drying and storage practices, inadequate monitoring of processors aggravated the situation. Nonetheless, all interviewed processors expressed willingness to participate in training programs to ensure quality and safety along the chain. The study findings underscore the necessity for targeted interventions to reduce aflatoxin risks in the spice value chain. These should include strengthened food safety inspections and enforcement, as well as tailored training and support for micro and small-scale spice processors. Enhancing their knowledge and ability to adopt proper handling, drying and storage practices is critical for enhancing food safety and safeguarding public health.
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Open Access January 02, 2025

Ambient Air Quality and Human Health Risk Assessment of Heavy Metals in a Potentially Toxic Silver-Polluted Environment

Abstract Silver nanoparticles (Ag+NPs) contamination in the environment is a serious concern. This study investigated selected heavy metal (Ag+, Cd2+, Cr2+ and Pb2+) concentrations at different sampling points to assess the risk to human health (infants, children, and adults). To do this, an enclosed area (laboratory) of 12.6 m X 8.5 m (107.1 [...] Read more.
Silver nanoparticles (Ag+NPs) contamination in the environment is a serious concern. This study investigated selected heavy metal (Ag+, Cd2+, Cr2+ and Pb2+) concentrations at different sampling points to assess the risk to human health (infants, children, and adults). To do this, an enclosed area (laboratory) of 12.6 m X 8.5 m (107.1 m2) was clearly marked at different coded distances of S1, S2, S3, and S4 representing 2, 4, 6, and 8 m, while unpolluted atmosphere at 50 m away without Ag+NPs served as the control (S5). The silver fireworks were allowed to burn for an approximate 00h03m30s at each sampling points using a high-volume air sampler mounted at the Environmental Engineering Departmental Laboratory, Rivers State University, with windows and doors closed to simulate indoor conditions. Samples were digested using a mixture of analytical-grade nitric acid, analytical-grade hydrochloric acid and analyzed to evaluate the levels of heavy metals by atomic absorption spectrophotometry. The Ag+ result at S1 shows 30,000 µg/cm3, S2 was 29,000 µg/cm3, while S3 was 28000 µg/cm3 and then S4 was 13,000 µg/cm3. These results exceeded the permissible values of the United States National Ambient Air Concentration for rural, urban and industrial areas (0.0005, 0.004 and 0.6 µg/cm3, respectively). The result for the control (S5) (0.037 µg/cm3) was within the maximum allowable value. Results from other heavy metals such as Cd were 1000, 743, 401, 153, 0.001 µg/cm3, Cr was 5000, 4000, 3729, 2960, 0.002 µg/cm3, Pb was 0.048, 0.041, 0.035, 0.034 and 0.01, µg/cm3, respectively. However, higher values of Ag+, Cd, and Cr indicated a higher propensity for the metals to be toxic (bioavailable). In addition, the assessment of the potential health risk posed by these metals proved contaminated and harmful. Visitors recorded high values in exposure concentration (EC) and low values in average daily dose (ADD).
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Open Access November 10, 2023

Bioremediation of Heavy Metals in Crude Oil-Contaminated Utisol, Using Nutrient Formulate Produced from Jatropha tanjorensis Leaf Extract

Abstract This work evaluated the bioremediation potential of Jatropha tanjorensis leaf extract at different masses (250g, 500g and 750g) over a 40-day period. To achieve this, crude oil contamination of sandy loam soil was stimulated in twelve plastic reactors containing fixed masses of soil (4kg each) of topsoil homogenized with 500g of Bonny light crude oil. The Jatropha tanjorensis leaves were cultivated, rinsed with distilled water, blended, and purified by filtration. The leaf extract was applied at the stated concentrations including a control reactor (without leaf extract). The plastics reactors were kept in an open air shielded away from rainfall. The physicochemical characteristics determined were particle size distribution (PSD), potential of hydrogen (pH), electrical conductivity (EC), organic matter (OM), organic carbon (OC), selected heavy metals (Cr, Cd, Zn, Pb) and sample management were all in line with standard procedure. After 40 days of treatment, results obtained showed that plastic reactor with 750g of leaf extract produced the highest amount of cadmium reduction of 97% (from an initial of and there was significant difference among treatment (P < 0.05). The sequence of reduction among treatment was 750g > 500g > 250g of the leaf extract. Chromium, Lead and zinc followed similar trend. Thus, the Jatropha tanjorensis [...] Read more.
This work evaluated the bioremediation potential of Jatropha tanjorensis leaf extract at different masses (250g, 500g and 750g) over a 40-day period. To achieve this, crude oil contamination of sandy loam soil was stimulated in twelve plastic reactors containing fixed masses of soil (4kg each) of topsoil homogenized with 500g of Bonny light crude oil. The Jatropha tanjorensis leaves were cultivated, rinsed with distilled water, blended, and purified by filtration. The leaf extract was applied at the stated concentrations including a control reactor (without leaf extract). The plastics reactors were kept in an open air shielded away from rainfall. The physicochemical characteristics determined were particle size distribution (PSD), potential of hydrogen (pH), electrical conductivity (EC), organic matter (OM), organic carbon (OC), selected heavy metals (Cr, Cd, Zn, Pb) and sample management were all in line with standard procedure. After 40 days of treatment, results obtained showed that plastic reactor with 750g of leaf extract produced the highest amount of cadmium reduction of 97% (from an initial of and there was significant difference among treatment (P < 0.05). The sequence of reduction among treatment was 750g > 500g > 250g of the leaf extract. Chromium, Lead and zinc followed similar trend. Thus, the Jatropha tanjorensis leaf extract has the potential to ameliorate crude oil-contaminated soil.
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Open Access November 01, 2023

Individual Wave Component Signal Modeling, Parameters Extraction, and Analysis

Abstract The accurate estimation of Individual Wave Components (IWC) is crucial for automated diagnosis of the human digestive system in a clinical setting. However, this process can be challenging due to signal contamination by other signal sources in the body, such as the lungs and heart, as well as environmental noise. To address this issue, various denoising techniques are commonly employed in bowel [...] Read more.
The accurate estimation of Individual Wave Components (IWC) is crucial for automated diagnosis of the human digestive system in a clinical setting. However, this process can be challenging due to signal contamination by other signal sources in the body, such as the lungs and heart, as well as environmental noise. To address this issue, various denoising techniques are commonly employed in bowel sound signal processing. While denoising is important, it can increase computational complexity, making it challenging for portable devices. Therefore, signal processing algorithms often require a trade-off between fidelity and computational complexity. This study aims to evaluate an IWC parameter extraction algorithm that was previously developed and reconstruct the IWC without denoising using synthetic and clinical data. To that end, the role of a reliable model in creating synthetic data is paramount. The rigorous testing of the algorithm is limited by the availability of quality and quantity recorded data. To overcome this challenge, a mathematical model has been proposed to generate synthetic bowel sound data that can be used to test new algorithms. The proposed algorithm’s robust performance is evaluated using both synthetic and clinically recorded data. We perform time-frequency analysis of original and reconstructed bowel sound signals in various digestive system states and characterize the performance using Monte Carlo simulation when denoising is not applied. Overall, our study presents a promising algorithm for accurate IWC estimation that can be useful for predicting anomalies in the digestive system.
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Open Access September 22, 2023

Bioremediation of Total Polycyclic Aromatic Hydrocarbon in Crude Oil-Contaminated Soil using Costus afer Plant

Abstract Costus afer is a well-known medicinal plant abundant in the Niger Delta region of Nigeria. The successful growth of Costus afer plant on crude oil contaminated soil adds to the list of plants that has potential to get rid of harmful chemical compounds to save human life as well preserve the environment. This study investigates the remediation potential of Costus afer plant at different ages (7, 14, 21, 28, 35, and 42 days old) to decontaminate petroleum hydrocarbon-contaminated soil. To achieve this, contamination of sandy-loam soil was simulated by mixing T0.5, 1.0, and 1.5 L of Bonny-Light crude oil with 48 kg of the soil in three separate reactors to achieve conditions of low, medium, and high contamination, respectively. The reactor with medium-level contaminated soil served as the control. The plants were nursed and transplanted at the stated ages to each reactor except the control. Controlled irrigation was applied, and the setups were housed to shield them from rainfall. After 90 days of treatment, results showed that the 7 days old plants produced the highest amounts of total polycyclic aromatic hydrocarbon (TPAH) reduction of 99.71, 90.10, and 84.06 % in the soil with low, medium, and high contamination, respectively. Furthermore, the sequence of TPAH reduction by the plants was 14 days old > 21 days old > 28 days old > 35 days old > 42-days old. Thus, in addition to its medicinal value, Costus afer [...] Read more.
Costus afer is a well-known medicinal plant abundant in the Niger Delta region of Nigeria. The successful growth of Costus afer plant on crude oil contaminated soil adds to the list of plants that has potential to get rid of harmful chemical compounds to save human life as well preserve the environment. This study investigates the remediation potential of Costus afer plant at different ages (7, 14, 21, 28, 35, and 42 days old) to decontaminate petroleum hydrocarbon-contaminated soil. To achieve this, contamination of sandy-loam soil was simulated by mixing T0.5, 1.0, and 1.5 L of Bonny-Light crude oil with 48 kg of the soil in three separate reactors to achieve conditions of low, medium, and high contamination, respectively. The reactor with medium-level contaminated soil served as the control. The plants were nursed and transplanted at the stated ages to each reactor except the control. Controlled irrigation was applied, and the setups were housed to shield them from rainfall. After 90 days of treatment, results showed that the 7 days old plants produced the highest amounts of total polycyclic aromatic hydrocarbon (TPAH) reduction of 99.71, 90.10, and 84.06 % in the soil with low, medium, and high contamination, respectively. Furthermore, the sequence of TPAH reduction by the plants was 14 days old > 21 days old > 28 days old > 35 days old > 42-days old. Thus, in addition to its medicinal value, Costus afer plant also has the potential to restore crude oil-contaminated soils.
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Open Access August 17, 2024

Quality and Safety of Folded Vermicelli Produced by the Small-scale Processors in Tanga City, Tanzania

Abstract Tanga City is the region with several micro-and small-scale pasta processing companies in the country. Therefore, the purpose of this study was to assess the quality and safety of folded vermicelli produced by the small-scale processors in Tanzania. Samples of 1 kg folded vermicelli were collected from 14 processing companies, by the intentional cluster sampling technique. The samples were analysed for aflatoxin and microbiological (Escherichia coli, Aspergillus flavus, and Aspergillus parasiticus) quality. Moreover, physico-chemical quality was assessed in terms of diameter by using a digital calliper, moisture content by oven-drying method at 110℃± 5℃, breaking strength by the texture analyzer, and colour by colourimeter (Chroma Meter CR-400) of the collected samples were determined. In terms of microbial quality, the results indicated contamination by E. coli (1.25-3.00 Log CFU.g-1 in 8/14 samples), A. flavus (2.23-2.83 Log CFU.g-1 in 12/14 samples), and A. parasiticus [...] Read more.
Tanga City is the region with several micro-and small-scale pasta processing companies in the country. Therefore, the purpose of this study was to assess the quality and safety of folded vermicelli produced by the small-scale processors in Tanzania. Samples of 1 kg folded vermicelli were collected from 14 processing companies, by the intentional cluster sampling technique. The samples were analysed for aflatoxin and microbiological (Escherichia coli, Aspergillus flavus, and Aspergillus parasiticus) quality. Moreover, physico-chemical quality was assessed in terms of diameter by using a digital calliper, moisture content by oven-drying method at 110℃± 5℃, breaking strength by the texture analyzer, and colour by colourimeter (Chroma Meter CR-400) of the collected samples were determined. In terms of microbial quality, the results indicated contamination by E. coli (1.25-3.00 Log CFU.g-1 in 8/14 samples), A. flavus (2.23-2.83 Log CFU.g-1 in 12/14 samples), and A. parasiticus (1.22-2.75 Log CFU.g-1 in 2/14 samples) as they are beyond the set limits. The diameter varied between 0.90 mm to 1.73 mm in 9/14 samples and moisture content were 10.61% to 12.65% in 13/14 samples, being within the established parameters. The samples indicated low breaking strength with levels between 6.79x105 N.m-2 to 3.75x106 N.m-2 in 11/14 samples. The result of brightness (L*) were between 53.03 to 72.14 and yellowness (b*) between 13.68 to 19.48 indices, indicating that there was no significant difference at the 5% level, respectively, although 2/14 samples had red (a*) colour values (-1.32 – +0.56). However, 4/14 samples were detected with aflatoxin B1 (0.60-0.70 μg.kg-1), they are within the recommended level (5 μg.kg-1). The study underscores the need for concerted efforts to enhance production and hygiene practices to ensure consistent compliance with quality and safety standards.
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Open Access June 30, 2024

Phytostabilization of Total Monocyclic Aromatic Hydrocarbon in Crude Oil-Contaminated Oxisol using Costus afer Plant

Abstract Costus afer, a known medicinal plant used in the removal of total monocyclic aromatic hydrocarbon (TMAH) in crude oil-contaminated soil add to the list of plant that has the potential to restore the soil quality. This study investigated the potential of Costus afer plant at various ages (7, 14, 21, 28, 35, and 42 days old) to biodegrade crude oil-contaminated soil. The group-balanced block design (GBBD) was used in establishing the experiment. TMAH was quantified by the standard method, according to USEPA method using gas chromatography-mass spectrometry (GC-MS). The contamination of 48kg of sandy loam soil was simulated by mixing 0.5, 1.0, and 1.5L of Bonny-Light crude oil with the soil in three separate vessels to achieve conditions of low (C1), medium(C2), and high(C3) contamination, respectively. An additional vessel with medium-level contaminated soil but no treatment (C4) served as the control. The Costus afer plants were nursed and transplanted at the stated ages to each vessel except the control. Controlled irrigation was applied, and the setups were housed to shield them from rainfall. After 90 days of treatment, results showed that the 7 days old Costus afer plants produced the highest amount of TMAH reduction of 96.5, 39.8, and 32.1%, for C1, C2 and C3, respectively, while the control (C4) was 9.45%. Furthermore, the sequence of TMAH reduction by the plants was 7 days old, 14 days old, 21 days old, 28 days old, 35 days old, and 42 days old. Thus, in addition to its medicinal value, Costus afer [...] Read more.
Costus afer, a known medicinal plant used in the removal of total monocyclic aromatic hydrocarbon (TMAH) in crude oil-contaminated soil add to the list of plant that has the potential to restore the soil quality. This study investigated the potential of Costus afer plant at various ages (7, 14, 21, 28, 35, and 42 days old) to biodegrade crude oil-contaminated soil. The group-balanced block design (GBBD) was used in establishing the experiment. TMAH was quantified by the standard method, according to USEPA method using gas chromatography-mass spectrometry (GC-MS). The contamination of 48kg of sandy loam soil was simulated by mixing 0.5, 1.0, and 1.5L of Bonny-Light crude oil with the soil in three separate vessels to achieve conditions of low (C1), medium(C2), and high(C3) contamination, respectively. An additional vessel with medium-level contaminated soil but no treatment (C4) served as the control. The Costus afer plants were nursed and transplanted at the stated ages to each vessel except the control. Controlled irrigation was applied, and the setups were housed to shield them from rainfall. After 90 days of treatment, results showed that the 7 days old Costus afer plants produced the highest amount of TMAH reduction of 96.5, 39.8, and 32.1%, for C1, C2 and C3, respectively, while the control (C4) was 9.45%. Furthermore, the sequence of TMAH reduction by the plants was 7 days old, 14 days old, 21 days old, 28 days old, 35 days old, and 42 days old. Thus, in addition to its medicinal value, Costus afer plant also has the potential to biodegrade TMAH in crude oil-contaminated sandy loam soil.
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Open Access February 07, 2023

Relations between Dentistry and COVID-19 Infections

Abstract As a result of the virus's global dissemination, novel COVID-19 infections have emerged as a significant obstacle for all healthcare professionals to overcome. Dental specialist plays an effective role in the prevention of coronavirus. Dental care units and settings face various problems relating to the transmission of disease during treatment and dental operations. Blood, saliva, and mixed water [...] Read more.
As a result of the virus's global dissemination, novel COVID-19 infections have emerged as a significant obstacle for all healthcare professionals to overcome. Dental specialist plays an effective role in the prevention of coronavirus. Dental care units and settings face various problems relating to the transmission of disease during treatment and dental operations. Blood, saliva, and mixed water droplets possessing the virus cause contamination of equipment used for dental treatment. Both patients and workers may become transmitters and infectors of COVID-19 through direct contact during dental operations. Both dental workers and patients are likely to become infectors and transmitters of COVID-19. The dental care routine is very effective as we discussed below the prevention steps are very effective. All healthcare workers at the dentistry clinics, including nurses, should collaborate to prevent the spread of the COVID-19 virus among patients.
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Open Access February 04, 2023

Microbial Quality of Home Prepared Complementary Foods in Slum Households with Children of Age 6-24 Months in Addis Ababa: A Community Based Cross-sectional Study

Abstract Background: Foodborne disease is a worldwide challenge. It causes a huge burden of diarrhea in children mostly in developing countries and this is common during the complementary feeding periods. As home serve as the proliferation ground for microbial pathogens, home- prepared complementary foods, coupled with unhygienic feeding practice and contamination, it is the cause of child morbidity and poor nutritional status. This is worse in slum households. However, recent evidence is very scarce and further study is very necessary. Objective: To investigate the microbiological quality of home-prepared complementary foods in slum households with children of 6-24 months in Addis Ababa, 2021. Methods: A community-based cross-sectional study design was used and a total of 91 households were included. Three sub-cities in Addis Ababa and slum settlements within each sub-city were randomly selected by lottery method. Households with children of age from 6-24 months were selected by systematic random sampling. Laboratory investigation was used for microbial identification and excel sheet was used for data entry and cleaning. SPSS V. 23 was used for data analysis. Result: The median and interquartile range of aerobic plate count, S.aureus, yeast, molds and total coliforms are log5.75cfu/ml, Log1.84cfu/ml; Log4.7cfu/ml, Log5.46cfu/ml; Log5.29 cfu/ml, Log3.68cfu/ml; Log4.17cfu/ml, Log4.70cfu/ml; and Log0, Log3.5cfu/ml, respectively. Fecal coliform and E.coli were observed in 19% and 10% of complementary food samples. Conclusion: The load of aerobic plate count, S.aureus [...] Read more.
Background: Foodborne disease is a worldwide challenge. It causes a huge burden of diarrhea in children mostly in developing countries and this is common during the complementary feeding periods. As home serve as the proliferation ground for microbial pathogens, home- prepared complementary foods, coupled with unhygienic feeding practice and contamination, it is the cause of child morbidity and poor nutritional status. This is worse in slum households. However, recent evidence is very scarce and further study is very necessary. Objective: To investigate the microbiological quality of home-prepared complementary foods in slum households with children of 6-24 months in Addis Ababa, 2021. Methods: A community-based cross-sectional study design was used and a total of 91 households were included. Three sub-cities in Addis Ababa and slum settlements within each sub-city were randomly selected by lottery method. Households with children of age from 6-24 months were selected by systematic random sampling. Laboratory investigation was used for microbial identification and excel sheet was used for data entry and cleaning. SPSS V. 23 was used for data analysis. Result: The median and interquartile range of aerobic plate count, S.aureus, yeast, molds and total coliforms are log5.75cfu/ml, Log1.84cfu/ml; Log4.7cfu/ml, Log5.46cfu/ml; Log5.29 cfu/ml, Log3.68cfu/ml; Log4.17cfu/ml, Log4.70cfu/ml; and Log0, Log3.5cfu/ml, respectively. Fecal coliform and E.coli were observed in 19% and 10% of complementary food samples. Conclusion: The load of aerobic plate count, S.aureus, yeast, molds, and total coliform are high in samples of complementary foods. Therefore, intervention studies for further identification of contamination sources should be made in order to minimize contamination of complementary foods and associated infections.
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