Aflatoxins contamination of maize exhibits a serious threat to human and animal health over the past few decades. To protect the safety of food commodities, regular monitoring for afltoxins in food is necessary. In the proposed study, we have followed a rapid and sensitive biosensor approach as well as thin layer chromatography method for quantification of aflatoxins. Our data demonstrate that all the samples tested were beyond the safety level of aflatoxins as determined by Food and Drug Administration and European Union. Results of fungal mycoflora evidenced the massive presence of Aspergillus species (75 %) followed by Fusarium (11 %), Penicillium (8 %) and Trichoderma (6 %) as characterized by biochemical and sporulation properties. Use of internationally developed biosensor for detection of fungal toxin in this work is the first approach that was utilized in the developing country like Ethiopia. In the end, we conclude that fungal contaminant and there metabolites are potential threat to the agricultural industry and require urgent intervention.

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This study was conducted to determine the spatial levels of chromium contamination of water, agricultural soil, and vegetables in the leather tanning industrial areas using spectrophotometric methods. The results showed elevated accumulation of total Cr ranging from 10.85 ± 0.885 mg/L to 39.696 ± 0.326 mg/L, 16.225 ± 0.12 mg/Kg to 1581.667 ± 0.122 mg/Kg, and 1.0758 ± 0.05348 mg/Kg to 11.75 ± 0.206 mg/Kg in water, agricultural soil, and vegetable samples, respectively. The highest levels of chromium (VI) found from the speciation study were 2.23 ± 0.032 mg/Kg and 0.322 ± 0.07 mg/L in soil and water samples, respectively, which decreased with distance from the tannery. Among the vegetables, the highest load of Cr(VI) was detected in onion root (0.048 ± 0.065 mg/Kg) and the lowest (0.004 ± 0.007 mg/Kg) in fruit of green pepper. The detected levels of Cr in all of the suggested samples were above the WHO permissible limits. The variations of the levels Cr(III) and Cr(VI) contamination of the environment with distance from the tannery were statistically significant (p = 0.05). Similarly, significant difference in the levels of Cr among the tested vegetables was recorded. The levels increased with decreasing distance from the effluent channel.

Surfaces made of entangled networks of single-walled carbon nanotubes (SWCNTs) display a strong adsorption affinity for aromatic hydrocarbons. Adsorption of these compounds onto the walls of SWCNTs changes the electrical characteristics of the SWCNT-solution interface. Using these features, we have developed a potentiometric sensor to detect neutral aromatic species. Specifically, we can detect online aromatic hydrocarbons in industrial coolant water. Our chromatographic results confirm the adsorption of toluene onto the walls of carbon nanotubes, and our impedance spectroscopy data show the change in the double layer capacitance of the carbon nanotube-solution interface upon addition of toluene, thus confirming the proposed sensing mechanism. The sensor showed a toluene concentration dependent EMF response that follows the shape of an adsorption isotherm and displayed an immediate response to the presence of toluene with a detection limit of 2.1 ppm. The sensor does not respond to other nonaromatic hydrocarbons that may coexist with aromatic hydrocarbons in water. It shows a qualitative sensitivity and selectivity of 100% and 83%, respectively, which confirms its ability to detect aromatic hydrocarbons in aqueous solutions. The sensor showed an excellent ability to immediately detect the presence of toluene in actual coolant water. Its operational characteristics, including its fast response, low cost, portability, and easy use in online industrial applications, improve those of current chromatographic or spectroscopic techniques.

Certain natural dietary spices, in addition to their use in food flavoring and preservation, have the ability to detoxify or degrade a wide range of chemical carcinogens. In the present study, aqueous extracts of judiciously selected natural dietary spices were evaluated for their ability to degrade aflatoxin B1 (AFB1). A total of 9 spices including garlic (Allium sativum), ginger (Zingiber officinale), black cumin (Nigella sativum), clove (Syzygium aromaticum), sacred basil (Ocimum basilicum), lemon grass (Cymbopogon citratus L. (DC) Stapf)), thyme (Thymus schimperi), fenugreek (Trigonella foenum-graecum), and lemon traditionally used by the Ethiopian Community for food flavoring and preservation were considered. Aflatoxin degradation efficacy of the spice extracts was studied through determination of the toxin in extract-treated and nontreated samples using LC-MS/MS. The degradation was characterized by electrochemical methods based on the characteristic oxidation peak of phenolic hydroxyl resulting from the degradation of the toxin after treatment with the extracts. Of the various spices, garlic showed the highest 35.8% (30 min) to 61.7% (1 hr) in spiked and 46.7% (30 min) to 68.3% (1 hr) and real-sample (contaminated maize) treatment reduction followed by lemon 34.2% (30 min) to 56.0% (1 hr) in spiked and 41.1% (30 min) to 60.6% (1 hr) in real-sample treatment at 25°C. The level of reduction was higher in real-sample treatment than that in spiked. This suggests adsorptive contribution by the matrix in addition to the chemical degradation. The current findings revealed nonobvious benefits of the use of natural dietary spices as effective solution for AFB1 degradation and decontamination of food.