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For some, chestnuts are an essential snack all year round due to their high nutritional value, but in their roasted form, they are a staple piece during the Christmas season [1]. They have medicinal value in that they promote good gut health by synthesising isomalto-oligosaccharides, which in turn encourages Lactobacilli proliferation, but research has also shown chestnut-derivatives to be effective in promoting apoptosis in human cervical cancer cells [1]. Unfortunately, due to their high-water content, they are highly susceptible to food rot during harvesting and storage; one of the microbial causes of this is Neofusicoccum parvum, which is a pathogenic plant fungus [1]. The mechanism behind infection is not wholly clear, but research suggests that production of toxins is a common cause [1]. To optimise crop yield and improve economic stance, it is imperative that infection of this fungus is controlled and reduced, hence an increase in research in antifungal food treatment [1].
Natamycin, which is has been used in the food preservation industry for over 30 years, is an environmentally friendly antifungal macrolide produced by fermentation of Actinomycetes strains [2]. The mechanism behind its effectiveness is down to binding of the hydrophobic macrolide double bond to sterol molecules in the fungal cytoplasmic membrane [1]. Permeability of the fungal cytoplasmic membrane is then increased, allowing macromolecules, such as proteins, to flow out [1].
Earlier this year, Gou et al. investigated the antifungal activity of natamycin against N. parvum on chestnut fruits by agar minimal inhibitory concentration (MIC) testing [1]. The concentrations of natamycin tested ranged from 10 to 200 μg/mL, and it was found that the MIC was 100 μg/mL, whilst also having a minimal inhibitory fungicidal concentration (MFC) of 200 μg/mL [1]. In addition, they investigated the mechanism behind its effectiveness and results supported the pre-existing notion that damage to
the cell membrane and content leakage is the
primary cause of good antifungal activity [1].
Advances in this area of research is encouraging to not only chestnut crop farmers, but the agricultural industry, and provides hope for the efficient preservation of crops and treatment of food rot.
In the DWS microbiology laboratory, we specialise in conducting Minimal Inhibitory Concentration (MIC) testing of several fastidious microbes. Do you have an antimicrobial product in development? Maybe we could help. Contact us today by calling on +44 (0)1274 595728 or complete our online contact form below.
References
- Gou L-J, Liu T-T, Zeng Q, Dong W-R, Wang L, Long S, et al. Natamycin has an inhibitory effect on neofusicoccum parvum, the pathogen of chestnuts. Molecules. 2023;28(9):3707. doi:10.3390/molecules28093707
- Meena M, Prajapati P, Ravichandran C, Sehrawat R. Natamycin: A natural preservative for food applications—a review. Food Science and Biotechnology. 2021;30(12):1481–96. doi:10.1007/s10068-021-00981-1
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