This study focused on the isolation, characterization, and evaluation of the antimicrobial and antioxidant activities of a crude extract from Bacillus subtilis isolated from rhizosphere soil. Through biochemical and physiological assessments, followed by whole genome sequencing, the isolate was confirmed as Bacillus subtilis BSP1. We examined the antimicrobial activity of B. subtilis BSP1 metabolites against various pathogenic bacteria and fungi. To enhance its antibacterial efficacy, we optimized the fermentation medium to maximize the secretion of antibacterial agents. Our findings demonstrated that the crude extract exhibited notable antimicrobial properties against various pathogenic bacterial and fungal isolates. The antioxidant test revealed a dose-dependent increase in the extract’s DPPH scavenging activity and reducing power, with an impressive 98.9% DPPH scavenging activity at 30 mg/mL. Importantly, safety assessments indicated a lack of hemolytic activity on human red blood cells, with only 1.3% hemolysis at 100 mg/mL, suggesting its potential suitability for practical applications. In summary, Bacillus subtilis BSP1, isolated from soil, appears to be a promising candidate for antibiotic production. Its significant antimicrobial and antioxidant properties, combined with its safety profile, highlight its potential applications in medicine, agriculture, and biotechnology.

Mycotoxins are toxic compounds produced as secondary metabolites by certain types of filamentous fungi under specific conditions. The contamination of nuts and nut-related products with mycotoxins is a significant global concern due to their severe consequences on human health, including carcinogenicity and immunosuppression. Aflatoxins, with a particular emphasis on aflatoxin B1, are the most common and toxic mycotoxins found in human food. Aflatoxin B1 (AFB1) is known to be highly toxic and carcinogenic. Consequently, global food regulatory organizations have established permissible levels for mycotoxins in nuts. Numerous methodologies have been developed for the detection of mycotoxins in nuts. However, high-performance liquid chromatography (HPLC) and ultra-high-performance liquid chromatography coupled with triple quadrupole mass spectrometry (UHPLC-QqQ-MS/MS) have shown clear benefits in terms of effectiveness and sensitivity. This review aims to provide a comprehensive overview of the major mycotoxins found in nuts, their physiological effects, and their worldwide prevalence. Additionally, the review will focus on nut sample pretreatment methods, analytical techniques employed for mycotoxin detection in nuts, and recent advancements in materials and solvents used for this purpose. Significant gaps exist in mycotoxin detection in nuts, including methodological variability and insufficient data from certain nut-producing countries that need further exploration in the future.

This study examines the prevalence of aflatoxin contamination in 160 nut samples, both shelled and unshelled (including pistachios, peanuts, and walnuts), from the Lebanese market, focusing on their fungal contamination and specific toxigenic strains. Aflatoxin B1 (AFB1), known for its potent carcinogenic and immunosuppressive properties, was detected in various samples. Moisture content analysis showed that unshelled nuts often exceeded maximum moisture limits more frequently than shelled nuts, with levels ranging from 1.9 to 9.5%. The predominant fungal genus identified through cultivation on potato dextrose agar (PDA) plates was Aspergillus. In total, 55% of samples were contaminated with A. flavus and 45% with A. niger. All toxigenic strains isolated were identified as Aspergillus flavus. The aflatoxins, particularly AFB1, were quantified using the enzyme-linked immunosorbent assay (ELISA) and reversed-phase high-performance liquid chromatography (HPLC), revealing contamination in 43.8% of the samples, with concentrations ranging from 0.4 to 25 µg/kg. Some samples notably exceeded the established maximum tolerable limits (MTLs) for AFB1, set between 2 and 8 µg/kg. Shelled pistachios showed the highest contamination rate at 52% and were the most frequent to surpass the MTL of 8 µg/kg for pistachios, whereas walnuts displayed the lowest contamination levels, with only 15.4% exceeding the MTL for aflatoxins.