This study was conducted to investigate the natural co-occurrence of 295 fungal and bacterial metabolites in 28 samples of dried date palm fruits collected from different shops distributed in Assiut Governorate, Upper Egypt in 2016. Extraction and quantification of the target analytes were done using the “dilute and shoot” approach followed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis. In total, 30 toxic fungal metabolites were detected. Among these metabolites, 4 types of ochratoxins including ochratoxin type A and B were quantified in 3 samples (11%) with a contamination range from 1.48 to 6070 μg/kg for ochratoxin A and from 0.28 to 692 μg/kg for ochratoxin B. In addition, fumonisin B2 was observed in 2 (7%) samples with contamination levels ranging from 4.99 to 16.2 μg/kg. The simultaneous detection of fumonisin B2 in the same contaminated samples with ochratoxins indicates the fungal attack by Aspergillus niger species during storage. Only 1 sample was contaminated with aflatoxin B1 (14.4 μg/kg) and B2 (2.44 μg/kg). The highest maximum concentration (90400 μg/kg) was for kojic acid that contaminated 43% of the samples. To the best of the authors’ knowledge, this is the first report of the natural co-occurrence of fumonisin B2 and ochratoxin A and B in addition to a wide range of other fungal metabolites in date palm fruits.
Mycotoxins are secondary metabolites produced by different fungi. These metabolites pose a potential risk on human health since they contaminate many food commodities. Among these, date palm fruits which are an integral part of diet in several countries. Therefore, detection of mycotoxins is a prerequisite to insure the safety of food. Here, different types of mycotoxins have been detected in levels that may have health hazard.
Anaerobic digestion for biogas production is one of the most used technology for bioenergy. However, the adoption of nanoparticles still needs further studies. Therefore, this study was designed to examine the effect of metal oxide nanoparticles (MONPs) at four different concentrations in two different combinations, 20 (R1) and 100 (R2) mg/L for Fe2O3, 100 (R3) and 500 (R4) mg/L for TiO2, and a mixture of Fe2O3 and TiO2 at rates of 20, 500 (R5) and 100, and 500 (R6), on hydrogen sulfide (H2S) mitigation, biogas, and methane (CH4) yield during the anaerobic digestion of cattle manure (CM) using an anaerobic batch system. The results showed that H2S production was 2.13, 2.38, 2.37, 2.51, 2.64, and 2.17 times lower than that of the control (R0), respectively, when the CM was treated by the aforementioned MONPs. Additionally, biogas and CH4 production were 1.09 and 1.105, 1.15 and 1.191, 1.07 and 1.097, 1.17 and 1.213, 1.10 and 1.133, and 1.13 and 1.15 times higher than those of R0 when R1, R2, R3, R4, R5, and R6 were supplemented with MONPs, respectively. The highest specific production of biogas and CH4 was 336.25 and 192.31 mL/gVS, respectively, which was achieved by R4 supplemented with 500 mg/L TiO2 NPs, while the corresponding values in the case of R0 were 286.38 and 158.55 mL/gVS