Forty-three species and variety belonging to 15 genera were collected from 30 strawberry fruit samples on Glucose-Czapek's agar medium. Among them, Aspergillus flavus, Aspergillus niger and Penicillium citrinum were the most frequent species recovered from 53.3%, 70.0% and 50.0% of the samples, respectively. According to the ITS rDNA sequence, we confirmed the morphological identification result. Moreover, aflatoxin biosynthesis gene omt-A was detected in A. flavus, while Aopks gene was found in A. niger. Interestingly, we could not detect any aflatoxin or ochratoxin biosynthesis genes in the P. citrinum strain. The concentration of detected aflatoxin was 3.5 ppb produced by A. flavus, while A. niger gave 4.1 ppb as ochratoxin. A. flavus was the most pectinase producer among the selected strains, and the highest amount was obtained at 30°C after 6 days of incubation with initial medium pH 8.
Essential oils are natural antimicrobial agents that can be used to control fungal and mycotoxin contamination. Although there are numerous reports discussing the fungal and mycotoxin contamination of foods, there are few researches on baby food contamination so this work aimed to determine the fungal and mycotoxin contamination in cerelac, cornflakes and milk powder and tried to control the mycotoxigenic strain growth and their production of mycotoxins by using essential oils. Cornflakes were heavily contaminated (24 species including 9 genera), while cerelac and milk powder were less contaminated. Aspergillus and Penicillium were the prevalent genera. The produced aflatoxins and ochratoxins from the tested strains of Aspergillus flavus and A. niger were extracted and estimated by fluorometric method. We used the 18S rRNA sequence technique to identify the genotypes of the three isolates. Two isolates were identified as Aspergillus niger and the third isolate as A. flavus. Omt‐A gene was detected in the A. flavus, while Aopks gene was detected in A. niger isolates. Amongst the five used essential oils, only cumin and peppermint oil depressed the mycotoxigenic strain growth and peppermint oil had the highest result. Its inhibitory effect on aflatoxin and ochratoxin production was evaluated. Aflatoxin production was highly reduced by 52.1%, but ochratoxin inhibition was very low, 4.88% and 3.17% by A. niger obtained from cornflakes and milk powder, respectively. The three tested samples were contaminated by ochratoxins, but cerelac and milk powder samples were free of aflatoxins. Cornflakes sample recorded the highest reading for both toxins.
Spices are portions of plants because their properties are used as colorants, preservatives, or medicine. The employments of spices have been known since long time, and the interest in the capability of spices is astounding because of the chemical compounds contained in spices. The molds grow on a variety of different crops and foodstuffs including spices often under warm and humid conditions. The mycobiota of five spice species were surveyed. Forty‐six fungal species were obtained. Aspergillus flavus and A. niger were the prevalent species recorded. The aflatoxins (AFs) and ochratoxins (OTs) were detected in some samples and isolates. Cumin had the highest concentration of AFs 8.2 ppb, while ginger had a considerable occurrence of OTs 6.7 ppb. A. flavus obtained from ginger recorded the maximum concentration of AFs 7.5 ppb, and A. niger from turmeric was the highest producer for OTs 3.6 ppb. omt‐A and Aopks genes were detected in all tested A . flavus isolates and two out of four A. niger isolates. One of the important properties of spices is cancer etiology and prevention. Ginger and sage were the highest cytotoxic against four human tumor cell lines.
Nuts are the natural source of healthy lipids, proteins, and omega-3. They are susceptible to fungal and mycotoxins contamination because of their high nutritional value. Twenty-five species comprising 12 genera were isolated from 80 samples of dried fruits and nuts using the dilution plate method. Peanut recorded the highest level of contamination followed by coconut; almond and raisin were the lowest. Aspergillus was the most prevalent genus and A.niger, was the most dominant species. The morphological identification of the selected A.niger isolates as they were detected in high frequency of occurrence was confirmed by using 18SrRNA sequence. Ochratoxin biosynthesis gene Aopks was detected in the tested isolates. Lipase production by the selected A.niger isolates was determined with enzyme activity index (EAI) ranging from 2.02 to 3.28. A.niger-26 was the highest lipase producer with enzyme activity of 0.6 ± 0.1 U/ml by the trimetric method. Lip2 gene was also detected in the tested isolates. Finally, the antibacterial and antibiofilm efficiency of crude lipase against some human pathogens was monitored. Results exhibited great antibacterial efficacy with minimum bactericidal concentration (MBC) of 20 to 40 µl/100 µl against Escherichiacoli, Pseudomonasaeruginosa, Proteusmirabilis, and Methicillin-resistant Staphylococcusaureus (MRSA). Interestingly, significant anti-biofilm efficacy with inhibition percentages of 95.3, 74.9, 77.1 and 93.6% was observed against the tested pathogens, respectively.
T HE increasing resistance of pathogenic bacteria and fungi to remedies and their biofilm formation made it is obligatory to search for new, safer and more effective alternatives using medicinal plants. The present investigation aims to study the potency of Syzygium aromaticum (clove) aqueous extract mixture with antibiotics or rotaxane derivatives against 3 multi-drug resistant bacteria, 2 fluconazole resistant fungi strains, their biofilm, 3 aflatoxigenic Aspergillus flavus strains and aflatoxin biosynthesis. Some bioactive compounds and elements were obtained for clove extract by Fourier transform infrared (FTIR) spectroscopy and energy dispersive X-ray fluorescence (EDXRF) analysis and gas chromatography-mass spectroscopy (GC-MS). A 33.3 -60 mg/mL concentrations of S. aromaticum aqueous extract were sufficient as MBC against E. coli O157:H7, E. coli O121, and Staphylococcus aureus (MRSA) strains, respectively. In practically all combinations of extract, antibiotics, and rotaxane derivatives, synergistic or indifferent relations were detected. No antagonistic interactions were observed against bacteria. For C. albicans and C. glabrata concentrations 24.64 and 49.28 mg/mL of clove were observed as MFC, respectively. Conversely, A. flavus strains were not repressed. Combination of clove with fluconazole exposed synergistic interactions against C. albicans. Clove considerably suppressed biofilm formation with inhibition percentage of 81.99, 82.2, and 72.89% for E. coli (O157:H7 and O121) and S. aureus (MRSA), respectively. Furthermore, C. albicans biofilm was reduced and the inhibition percentage was 54%. The highest inhibition percentage of aflatoxin production using clove was 31.7%. This investigation suggests the clove aqueous extract to be a prospective broad spectrum antimicrobial composite alone or in combination.
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