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The occurrence of fungi on the commercial dietary supplements based on the milk thistle (Silybum marianum (L.) Gaertn.) available on Polish market
Summary Introduction: Milk thistle (Silybum marianum (L.) Gaertn.) is an important medicinal plant, its achenes contain a silymarin, which has a regenerating and stabilizing effect on liver cells. The milk thistle based dietary supplements are among the best-selling plant pharmaceuticals in the US and the UE. Objective: The goal of the experiment was to determine which – if any – fungi contaminated either the whole or ground milk thistle achenes, available on the Polish market. Methods: The mycological analyses were performed on 200 achenes, using deep-freeze blotter method. Ground material was assessed using agar test method. For each sample, 10 Petri dishes were used. The material was applied in five places per one Petri dish, with a micro scoop laboratory spatula. Then, Petri dishes with achenes and ground material were incubated at 20°C under alternating cycles of 12 h NUV light and 12 h darkness. The identification of fungi was performed using stereo microscope and compound microscope, if necessary. Results: The milk thistle achenes were infested with following fungi: Alternaria alternata, Alternaria sp., Aspergillus flavus, Aspergillus spp., Bipolaris sp., Cladosporium spp., Epicoccum nigrum, Fusarium spp., Melanospora simplex, Mucor spp., Penicillium spp., Phoma sp., Rhizopus stolonifer, Sarocladium strictum, Stemphylium botryosum, Trichothecium roseum, Ulocladium consortiale and Verticillium sp. Among them A. alternata predominated. Whereas, milled milk thistle achenes were occupied by Aspergillus flavus, A. niger, Aspergillus spp., Fusarium sp., Mortierella spp., Mucor spp., Penicillium spp. and R. stolonifer. Conclusion: Considering the significant fungal contamination of milk thistle achenes-based dietary supplements, it seems reasonable to introduce a system of achene control due to possible microbiological contamination.
Evaluation of the Use of Oregano and Coconut Hydrolates to Improve Onion Seed Quality
Onion seeds are often contaminated by pathogenic fungi, such as Botrytis spp., Fusarium spp., which decrease seed quality. The usage of hydrolates is an alternative method to chemical treatment, and is safe for the natural environment, human health and life. The aim of the experiment was the determination of the effect of treatment with oregano and coconut hydrolates on the quality of onion seeds. Germination, vigour and seed health of two samples of onion seeds were tested. Seed germination was evaluated according to ISTA Rules, seed health by agar test and vigour by seed speed and uniformity of germination. Seeds were treated with hydrolate solutions at concentrations of 10, 20, 50 and 100%; untreated seeds and seeds soaking in water and treated with fungicide were control. Generally, the use of hydrolates improved the germination capacity at first and final count for both analyzed samples. After treating with hydrolate solutions, less abnormal diseased seedlings were also observed. Higher concentrations of hydrolates were effective in the limitation of the incidence of fungi A. alternata, Cladosporium spp. and Fusarium spp., either by complete elimination or a reduction of their presence on the seeds.
Effect of acetic acid treatments and storage on the quality of lettuce (Lactuca sativa L.) seeds
Seedborne fungi negatively affect the quality of lettuce (Lactuca sativa L.) seeds and they are impact on their storability. Using the acetic acid can be an alternative to chemical treatment. Seeds were soaked for 30 minutes in a solution of acetic acid at concentrations of 0.25%, 0.5%, and 2%. Untreated seeds, seeds soaked for 30 minutes with distilled water and seeds treated with Dithane NeoTec 75 were controls. Seeds germination, vigour and seed health before and after 18 months of storage at 4 and 20 °C were tested. Before storage the acetic acid solution at concentrations of 0.25 and 0.5% significantly decreased number of dead seeds and increased germination at first and final counts, 2.0% solution worsened germination and vigour of seeds of both samples. Generally acetic acid solutions limited occurrence of fungi. Seeds stored at a lower temperature (4 °C) were characterized by significantly higher percentages of total germinating seeds (Gmax) and percentage of germination at first and final counts. Deterioration of the germination at first and final counts was found only after soaking the seeds in acetic acid solution at a concentration of 2%. Acetic acid solutions at concentration 0.5 and 2.0% effectively reduced occurrence of Alternaria alternata.