The aim of this study was to differentiate surface-associated microflora and microorganisms resistant to washing in dry oat (Avena sativa L.) seeds and to evaluate the effect of 24 h maceration in sterile distilled water on microbial release. Commercial seed samples were processed aseptically in the microbiology laboratory. Two experimental phases were applied: (i) pre-maceration, where seeds were briefly rinsed in sterile distilled water and the suspension was analyzed for surface-associated microorganisms, and (ii) post-maceration, where seeds were soaked for 24 h, allowing the release of microorganisms resistant to washing and associated with protected seed-coat niches. Suspensions were filtered through 0.45 μm membranes and cultured on selective and differential media: nutrient agar for heterotrophs, m-Endo agar for total coliforms, m-FC agar for fecal coliforms, Salmonella–Shigella agar for enteric pathogens, and potato dextrose agar (PDA) for yeasts and molds. Results showed that before maceration, the highest microbial load was fecal coliforms (244 CFU/100 mL), followed by heterotrophs and total coliforms (39 CFU/100 mL), while no yeasts or molds were detected. After maceration, microbial counts decreased by 41% for fecal coliforms, 90% for Salmonella/Shigella, and more than 90% for heterotrophs. These findings indicate that dry oat seeds may harbor potentially harmful microorganisms not only on the surface but also tightly associated with protected structures of the seed coat. The internal presence of microorganisms has important implications for agriculture, as it may adversely affect seed germination and early plant de- velopment in the field, thereby reducing growth quality and productivity. Maceration combined with membrane filtration represents a simple and effective approach to detect these risks, with direct relevance for seed quality control and food safety.
Acuff, J. C., Dickson, J. S., Farber, J. M., Grasso-Kelley, E. M., Hedberg, C., Lee, A. et al. 2023. Practice and progress: updates on outbreaks, advances in research, and processing technologies for low-moisture food safety. Journal of Food Protection, 86(1), 100018.
https://doi.org/10.1016/j.jfp.2022.11.010
Agarwal, V. K. and Sinclair, J. B. 1997. Principles of Seed Pathology. 2nd ed. CRC Press, Boca Raton.
https://doi.org/10.1201/9781482275650
Anthero, A. G. S., Lima, J. M., Cleto, P. B., Jorge, L. M. M. and Jorge, R. M. M. 2019. Modeling of maceration step of the oat (Avena sativa) malting process. Journal of Food Process Engineering, 42(7), e13266.
https://doi.org/10.1111/jfpe.13266
Butt, M. S., Tahir-Nadeem, M., Khan, M. K. I., Shabir, R. and Butt, M. S. 2008. Oat: unique among the cereals. European Journal of Nutrition, 47(2), 68‒79.
https://doi.org/10.1007/s00394-008-0698-7
CXC 75-2015. Code of hygienic practice for low-moisture foods. Codex Alimentarius.
Dell’Olmo, E., Tiberini, A. and Sigillo, L. 2023. Leguminous seedborne pathogens: seed health and sustainable crop management. Plants, 12(10), 2040.
https://doi.org/10.3390/plants12102040
Desjardins, A. E. 2006. Fusarium Mycotoxins: Chemistry, Genetics, and Biology. APS Press.
Desjardins, A. E. and Proctor, R. H. 2007. Molecular biology of Fusarium mycotoxins. International Journal of Food Microbiology, 119(1–2), 47–50.
https://doi.org/10.1016/j.ijfoodmicro.2007.07.024
EFSA (European Food Safety Authority). 2011. Scientific opinion on the risks for animal and public health related to the presence of T-2 and HT-2 toxin in food and feed. EFSA Journal, 9(12), 2481.
https://doi.org/10.2903/j.efsa.2011.2481
EFSA. 2017. Risks to human and animal health related to the presence of deoxynivalenol and its acetylated and modified forms in food and feed. EFSA Journal, 15(9), e04718.
https://doi.org/10.2903/j.efsa.2017.4718
EFSA. 2022. Assessment of information as regards the toxicity of T-2 and HT-2 toxin for ruminants. EFSA Journal, 20(9), e07564.
https://doi.org/10.2903/j.efsa.2022.7564
EPA (United States Environmental Protection Agency). 2023. Method 1103.2: Escherichia coli (E. coli) in water by membrane filtration using membrane-thermotolerant Escherichia coli agar (mTEC).
https://www.epa.gov/system/files/documents/2024-06/method-1103.2-10022023_508.pdf
FAO (Food and Agriculture Organization of the United Nations). Food safety and quality: mycotoxins.
https://www.fao.org/food/food-safety-quality/a-z-index/mycotoxins/en/?utm_source=chatgpt.com (accessed 2025-10-18).
Forghani, F., den Bakker, M., Liao, J.-Y., Payton, A. S., Futral, A. N. and Diez-Gonzalez, F. 2019. Salmonella and enterohemorrhagic Escherichia coli serogroups O45, O121, O145 in wheat flour: effects of long-term storage and thermal treatments. Frontiers in Microbiology, 10, 323.
https://doi.org/10.3389/fmicb.2019.00323
Gebeyaw, M. 2020. Review on: Impact of seed-borne pathogens on seed quality. American Journal of Plant Biology , 5(4), 77‒81.
https://doi.org/10.11648/j.ajpb.20200504.11
ISO 4833-1:2013. Microbiology of the food chain ‒ Horizontal method for the enumeration of microorganisms ‒ Part 1: Colony count at 30 °C by the pour plate technique.
ISO 6579-1:2017. Microbiology of the food chain ‒ Horizontal method for the detection, enumeration and serotyping of Salmonella ‒ Part 1: Detection of Salmonella spp.
ISO 21528-1:2017. Microbiology of the food chain ‒ Horizontal method for the detection and enumeration of Enterobacteriaceae ‒ Part 1: Detection of Enterobacteriaceae.
ISTA (International Seed Testing Association). 2018. International rules for seed testing. https://www.seedtest.org/en/publications/international-rules-seed-testing.html
Kallistova, A., Nikolaev, Y., Grachev, V., Beletsky, A., Gruzdev, E., Kadnikov, V. et al. 2021. New insight into the interspecies shift of anammox bacteria Ca. “Brocadia” and Ca. “Jettenia” in reactors fed with formate and folate. Frontiers in Microbiology, 2022, 12, 802201.
https://doi.org/10.3389/fmicb.2021.802201
Liu, S., Roopesh, M. S., Tang, J., Wu, Q. and Qin, W. 2022. Recent development in low-moisture foods: microbial safety and thermal process. Food Research International, 155, 111072.
https://doi.org/10.1016/j.foodres.2022.111072
Logrieco, A., Moretti, A. and Solfrizzo, M. 2009. Alternaria toxins and plant diseases: an overview of origin, occurrence and risks. World Mycotoxin Journal, 2(2), 129‒140.
https://doi.org/10.3920/WMJ2009.1145
Munkvold, G. P. 2009. Seed pathology progress in academia and industry. Annual Review of Phytopathology, 47, 285–311.
https://doi.org/10.1146/annurev-phyto-080508-081916
Nelson, E. B. 2018. The seed microbiome: origins, interactions, and impacts. Plant and Soil, 422(1), 7‒34.
https://doi.org/10.1007/s11104-017-3289-7
Nikitina, A. A., Kallistova, A. Y., Grouzdev, D. S., Kolganova, T. V., Kovalev, A. A., Kovalev, D. A. et al. 2022. Syntrophic butyrate-oxidizing consortium mitigates acetate inhibition through a shift from acetoclastic to hydrogenotrophic methanogenesis and alleviates VFA stress in thermophilic anaerobic digestion. Applied Sciences, 13(1), 173.
https://doi.org/10.3390/app13010173
Pecchia, S., Caggiano, B., Da Lio, D., Cafà, G., Le Floch, G. and Baroncelli, R. 2019. Molecular detection of the seed-borne pathogen Colletotrichum lupini targeting the hyper-variable IGS region of the ribosomal cluster. Plants, 8(7), 222.
https://doi.org/10.3390/plants8070222
Peterson, D. M. 2001. Oat antioxidants. Journal of Cereal Science, 33(2), 115–129.
https://doi.org/10.1006/jcrs.2000.0349
Podolak, R., Enache, E., Stone, W., Black, D. G. and Elliott, P. H. 2010. Sources and risk factors for contamination, survival, persistence, and heat resistance of Salmonella in low-moisture foods. Journal of Food Protection, 73(10), 1919‒1936.
https://doi.org/10.4315/0362-028X-73.10.1919
Rose, D. J., Bianchini, A., Martinez, B. and Flores, R. A. 2012. Methods for reducing microbial contamination of wheat flour and effects on functionality. Cereal Foods World, 57(3), 104‒109.
https://doi.org/10.1094/CFW-57-3-0104
Salfinger, Y. and Tortorello, M. L. (eds) 2015. Compendium of Methods for the Microbiological Examination of Foods. 5th ed. APHA Press, Washington DC.
https://doi.org/10.2105/MBEF.0222
Selcuk, M., Oksuz, L. and Basaran, P. 2008. Decontamination of grains and legumes infected with Aspergillus spp. and Penicillium spp. by cold plasma treatment. Bioresource Technology, 99(11), 5104–5109.
https://doi.org/10.1016/j.biortech.2007.09.076
Shade, A., Jacques, M.-A. and Barret, M. 2017. Ecological patterns of seed microbiome diversity, transmission, and assembly. Current Opinion in Microbiology, 37, 15–22.
https://doi.org/10.1016/j.mib.2017.03.010
Tenno, T., Rikmann, E., Zekker, I. and Tenno, T. 2018. Modelling the solubility of sparingly soluble compounds depending on their particles size. Proceedings of the Estonian Academy of Sciences, 67(3), 300‒302.
https://doi.org/10.3176/proc.2018.3.10
Truyens, S., Weyens, N., Cuypers, A. and Vangronsveld, J. 2015. Bacterial seed endophytes: genera, vertical transmission and interaction with plants. Environmental Microbiology Reports, 7(1), 40–50.
https://doi.org/10.1111/1758-2229.12181
Uwineza, P. A., Urbaniak, M., Stępień, Ł., Gramza-Michałowska, A. and Waśkiewicz, A. 2024. Efficacy of Lamium album as a natural fungicide: impact on seed germination, ergosterol, and mycotoxins in Fusarium culmorum-infected wheat seedlings. Frontiers in Microbiology, 15, 1363204.
https://doi.org/10.3389/fmicb.2024.1363204
Whitehead, A., Beck, E. J., Tosh, S. and Wolever, T. M. S. 2014. Cholesterol-lowering effects of oat β-glucan: a meta-analysis of randomized controlled trials. The American Journal of Clinical Nutrition, 100(6), 1413‒1421.
https://doi.org/10.3945/ajcn.114.086108
WHO (World Health Organization). 2023a. Carbohydrate intake for adults and children: WHO guideline.
https://www.who.int/publications/i/item/9789240073593 (accessed 2023-07-17).
WHO. Mycotoxins. 2023b.
https://www.who.int/news-room/fact-sheets/detail/mycotoxins (accessed 2025-10-18).