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Background: Mycotoxins are produced in foods as a result of mold infection of crops before and after harvest. The aim of this report was to assess, for the first time in Tunisia, the contamination of red chili powder with Aflatoxins (AFs) and Ochratoxin A (OTA) and to identify the associated microbiota. Methods: Fifty-five samples of red Capsicum powder (Capsicum annuum) were screened for AFs and OTA and toxigenic fungal species. Mycotoxins were extracted using immunoaffinity columns and quantified by High Performance Liquid Chromatography (HPLC). Dilution method was realized for fungal isolation and confirmed Polymerase Chain Reaction (PCR) analysis. Data were statistically analysed using statistical software (version 5.0). Results: Mycotoxins levels in 5 out of 55 samples were above the European Union (EU) limit. The highest co-occurrence of mycotoxins was found between AFB1 and OTA (39/55 samples). Aspergillus flavus and Aspergillus niger were the most toxigenic species identified. The highest level of molds contamination found in Capsicum powder reached 7.91×106 Colony Forming Unit (CFU)/g. Conclusion: The co-occurrence of two important mycotoxins (OTA and AFB1) observed in this study, alarm us about the hygienic risk raised by Tunisian consumers and raise the need to improve the production process for red Capsicum powder in Tunisia. [ABSTRACT FROM AUTHOR]

Background: Ochratoxin A (OTA) and Aflatoxin B1 (AFB1) are toxic secondary metabolites produced by certain mold species. In this primarily survey, we examined the OTA and AFB1 contamination of pearl millet grains distributed in Tunisia. Methods: Twenty-five pearl millet (Pennisetum glaucum L.) samples from different regions of Tunisia were analyzed by High Performance Liquid Chromatography coupled with fluorescence detector in order to evaluate the contamination with of AFB1 and OTA. Statistical tests were performed with XLSTAT 2018. Results: AFB1 and OTA were detected in 32 and 28% millet samples, respectively. Mean amounts of these mycotoxins in the contaminated samples were of 24.54±17.54 µg/kg for OTA and 22.72±23.09 µg/kg for AFB1. Approximately, 28 and 24% of analyzed samples were found above the European Union limits for AFB1 and OTA, respectively. The estimated daily intake of OTA and AFB1 were 3.76 and 3.89 ng/kg b.w. per day, respectively. No significantly (p>0.05) difference in OTA and AFB1 contamination rate was found between samples taken from different regions. Conclusion: Consumption of millet in Tunisia might be an important contributing factor to the risk of dietary exposure to OTA and AFB1. [ABSTRACT FROM AUTHOR]

There is no deep understanding of the application of nanoparticles in water-based muds (WBM). Therefore, such study that helps to enhance the knowledge in the field of well stability using modern methods in an unforgiving industry is very much needed. The nanoparticles accumulate on the wellbore wall and due to their very small sizes, they seal the pores in the mud cake, which plasters the wellbore. This paper focuses on empirical aspects of using nano-bentonite for filter loss control. The current work was applied on a nano-drilling fluid to improve filtration characteristics of drilling fluid in the wellbore. Therefore, nano-bentonite WBM (size between 90 and 100 nm) was introduced as the smart drilling fluid with abilities to overcome the tight spot problem in wellbores, which has been investigated in the paper. Three different drilling fluids were prepared using nano-bentonite clay with the main focus of enhancing those rheological features of the fluid expected to improve the mud characteristics, especially the plastering properties. Low pressure low temperature (LPLT) filter press test has been utilized to calculate the filter loss volume and the viscosity, yield point and gel strength of the understudy samples and the results have been compared. It was found that the filtration loss during the LPLT test was reduced by an overall average of 34% for all of the three samples, resulting in better filtration characteristics. [ABSTRACT FROM AUTHOR]