Abstract
Almonds (Prunus dulcis (Miller) D.A. Webb) and European (sweet) chestnuts (Castanea sativa Miller) are of great economic and social impact in Mediterranean countries, and in some areas they constitute the main income of rural populations. Despite all efforts to control fungal contamination, toxigenic fungi are ubiquitous in nature and occur regularly in worldwide food supplies, and these nuts are no exception. This work aimed to provide knowledge on the general mycobiota of Portuguese almonds and chestnuts, and its evolution from field to the end of storage. For this matter, 45 field chestnut samples and 36 almond samples (30 field samples and six storage samples) were collected in Trás-os-Montes, Portugal. All fungi belonging to genus Aspergillus were isolated and identified to the section level. Fungi representative of other genera were identified to the genus level. In the field, chestnuts were mainly contaminated with the genera Fusarium, Cladosporium, Alternaria and Penicillium, and the genus Aspergillus was only rarely found, whereas almonds were more contaminated with Aspergillus. In almonds, Aspergillus incidence increased significantly from field to the end of storage, but diversity decreased, with potentially toxigenic isolates belonging to sections Flavi and Nigri becoming more significant and widespread throughout storage. These fungi were determined to be moderately associated, which can be indicative of mycotoxin co-contamination problems if adequate storage conditions are not secured.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Abdel-Gawad, K. M., & Zohri, A. A. (1993). Fungal flora and mycotoxins of six kinds of nut seeds for human consumption in Saudi Arabia. Mycopathologia, 124, 55–64.
Adebajo, L. O., & Popoola, O. J. (2003). Mycoflora and mycotoxins in kolanuts during storage. African Journal of Biotechnology, 2, 365–368.
Barreira, J. C., Pereira, J. A., Oliveira, M. B. P. P., & Ferreira, I. C. F. R. (2010). Sugars profiles of different chestnut (Castanea sativa Mill.) and almond (Prunus dulcis) cultivars by HPLC-RI. Plant Foods for Human Nutrition, 65, 38–43.
Bayman, P., Baker, J. L., & Mahoney, N. E. (2002). Aspergillus on tree nuts: incidence and associations. Mycopathologia, 155, 161–169.
da Silva, J. B., Pozzi, C. R., Mallozzi, M. A. B., Ortega, E. M., & Corrêa, B. (2000). Mycoflora and occurrence of aflatoxin B1 and Fumonisin B1 during storage of Brazilian sorghum. Journal of Agricultural and Food Chemistry, 48, 4352–4356.
Doster, M. A., Michailides, T. J., & Morgan, D. P. (1996). Aspergillus species and mycotoxins in figs from California orchards. Plant Disease, 80, 484–489.
Filtenborg, O., Frisvad, J. C., & Samson, R. A. (2004). Specific association of fungi to foods and influence of physical environmental factors. In R. A. Samson, E. S. Hoekstra, & J. C. Frisvad (Eds.), Introduction to food- and airborne fungi (7th ed., pp. 306–320). Wageningen: CBS.
Freire, F. C. O., Kozakiewicz, Z., & Paterson, R. R. M. (2000). Mycoflora and mycotoxins in Brazilian black pepper, white pepper and Brazil nuts. Mycopathologia, 149, 13–19.
Gams, W., Christensen, M., Onions, A. H., Pitt, J. I., & Samson, R. A. (1985). Infrageneric taxa of Aspergillus. In R. A. Samson & J. I. Pitt (Eds.), Advances in Penicillium and Aspergillus systematic (pp. 55–62). New York: Plenum Press.
Hoekstra, E. S., Samson, R. A., & Summerbell, R. C. (2004). Methods for the detection and isolation of fungi in the indoor environments. In R. A. Samson, E. S. Hoekstra, & J. C. Frisvad (Eds.), Introduction to food- and airborne fungi (7th ed., pp. 298–305). Wageningen: CBS.
Jimenez, M., Mateo, R., Querol, A., Huerta, T., & Hernandez, E. (1991). Mycotoxins and mycotoxigenic moulds in nuts and sunflower seeds for human consumption. Mycopathologia, 115, 121–127.
Joffe, A. Z. (1969). Relationship between Aspergillus flavus, A. niger and some other fungi in the mycoflora of groundnut kernels. Plant and Soil, 31, 57–64.
Kaaya, A. N., & Kyamuhangire, W. (2006). The effect of storage time and agroecological zone on mould incidence and aflatoxin contamination of maize from traders in Uganda. International Journal of Food Microbiology, 110, 217–223.
King, A. D., & Schade, J. E. (1986). Influence of almond harvest, processing and storage on fungal population and flora. Journal of Food Science, 51, 202–205.
King, A. D., Halbrook, W. U., Fuller, G., & Whitehand, L. C. (1983). Almond nutmeat moisture and water activity and its influence on fungal flora and seed composition. Journal of Food Science, 48, 615–617.
Klich, M. A. (2002). Identification of common Aspergillus species. Wageningen: CBS.
Klich, M. A. (2007). Environmental and developmental factors influencing aflatoxin production by Aspergillus flavus and Aspergillus parasiticus. Mycoscience, 48, 71–80.
Magan, N. (2006). Mycotoxin contamination of food in Europe: early detection and prevention strategies. Mycopathologia, 162, 245–253.
Maroco, J. (2003). Análise Estatística - Com utilização do SPSS (2nd ed.). Lisbon: Edições Sílabo, Lda.
Nakai, V. K., Rocha, L. O., Gonçalez, E., Fonseca, H., Ortega, E. M. M., & Corrêa, B. (2008). Distribution of fungi and aflatoxins in a stored peanut variety. Food Chemistry, 106, 285–290.
Phillips, D. J., Mackey, B., Ellis, W. R., & Hansen, T. N. (1979). Occurrence and interaction of Aspergillus flavus with other fungi on almonds. Phytopathology, 69, 829–831.
Purcell, S. L., Phillips, D. J., & Mackey, B. E. (1980). Distribution of Aspergillus flavus and other fungi in several almond-growing areas of California. Phytopathology, 70, 926–929.
Rodrigues, P., Venâncio, A., & Lima, N. (2012a). Aflatoxigenic fungi and aflatoxins in Portuguese almonds. The Scientific World Journal. doi:10.1100/2012/471926.
Rodrigues, P., Venâncio, A., & Lima, N. (2012b). Mycobiota and mycotoxins of almonds and chestnuts with special reference to aflatoxins. Food Research International, 48, 76–90.
Rosso, L., & Robinson, T. P. (2001). A cardinal model to describe the effect of water activity on the growth of moulds. International Journal of Food Microbiology, 6, 265–273.
Samson, R. A., Hoekstra, E. S., Lund, O., Filtenborg, O., & Frisvad, J. C. (2004). Methods for the detection, isolation and characterisation of food-borne fungi. In R. A. Samson, E. S. Hoekstra, & J. C. Frisvad (Eds.), Introduction to food- and airborne fungi (7th ed., pp. 283–305). Wageningen: CBS.
Sieber, T. N., Jermini, M., & Conedera, M. (2007). Effects of the harvest method on the infestation of chestnuts (Castanea sativa) by insects and moulds. Journal of Phytopathology, 155, 497–504.
Singh, P. K., & Shukla, A. N. (2008). Survey of mycoflora counts, aflatoxin production and induced biochemical changes in walnut kernels. Journal of Stored Products Research, 44, 169–172.
Teviotdale, B. L., & Hendricks, L. (1994). Survey of mycoflora inhabiting almond fruit and leaves in conventionally and organically farmed orchards. Acta Horticulturae, 373, 177–183.
Wareing, P. W., Nicolaides, L., & Twiddy, D. R. (2000). Nuts and nut products. In B. M. Lund, T. C. Baird-Parker, & G. W. Gould (Eds.), The microbiological safety and quality of food (pp. 919–940). Maryland: Aspen Publication.
Zak, J. C., & Willig, M. R. (2004). Fungal biodiversity patterns. In G. M. Mueller, G. F. Bills, & M. S. Foster (Eds.), Biodiversity of fungi: Inventory and monitoring methods (pp. 59–75). Waltham: Elsevier Academic Press.
Acknowledgments
P. Rodrigues was supported by grants SFRH/BD/28332/2006 from Fundação para a Ciência e a Tecnologia (FCT), and SFRH/PROTEC/49555/2009 from FCT and Polytechnic Institute of Bragança, Portugal.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Rodrigues, P., Venâncio, A. & Lima, N. Incidence and diversity of the fungal genera Aspergillus and Penicillium in Portuguese almonds and chestnuts. Eur J Plant Pathol 137, 197–209 (2013). https://doi.org/10.1007/s10658-013-0233-4
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10658-013-0233-4