Monitoring and Determination of Fungi and Mycotoxins in Stored Brazil Nuts

Abstract

Brazil nut (Bertholletia excelsa) is an important commodity from the Brazilian Amazon, and approximately 37,000 tons (3.36 × 10⁷ kg) of Brazil nuts are harvested each year. However, substantial nut contamination by Aspergillus section Flavi occurs, with subsequent production of mycotoxins. In this context, the objective of the present investigation was to evaluate the presence of fungi and mycotoxins (aflatoxins and cyclopiazonic acid) in 110 stored samples of cultivated Brazil nut (55 samples of nuts and 55 samples of shells) collected monthly for 11 months in Itacoatiara, State of Amazonas, Brazil. The samples were inoculated in duplicate onto Aspergillus flavus and Aspergillus parasiticus agar and potato dextrose agar for the detection of fungi, and the presence of mycotoxins was determined by high-performance liquid chromatography. The most prevalent fungi in nuts and shells were Aspergillus spp., Fusarium spp., and Penicillium spp. A polyphasic approach was used for identification of Aspergillus species. Aflatoxins and cyclopiazonic acid were not detected in any of the samples analyzed. The low water activity of the substrate was a determinant factor for the presence of fungi and the absence of aflatoxin in Brazil nut samples. The high frequency of isolation of aflatoxigenic Aspergillus section Flavi strains, mainly A. flavus, and their persistence during storage increase the chances of aflatoxin production on these substrates and indicates the need for good management practices to prevent mycotoxin contamination in Brazil nuts.

Fumigation of Brazil nuts with allyl isothiocyanate to inhibit the growth of Aspergillus parasiticus and aflatoxin production

“…These results demonstrate the problem with uncontrolled moisture in foods and the importance of combining several barriers to avoid microbial growth. The presence of Aspergillus species in Brazil nuts is very common, and its growth is supported by the damp and hot weather of the Amazon region. Then, a longer shelf life of Brazil nuts can be ensured by lowering and controlling the environmental moisture during storage and transportation.…”

Impact of postharvest processing on the fungal population contaminating African walnut shells (Tetracarpidium conophorum Mull. Arg) at different maturity stages and potential mycotoxigenic implications

“…were frequently isolated from cultures of African walnut shell pieces. These fungi are known to commonly occur in nuts (Rodrigues et al, 2012;Baquião et al, 2013). Their prevalence has been confirmed in Brazil nuts (Freitas-Silva and Venâncio, 2011), pistachio nuts (Khodavaisy et al, 2012), chestnut and walnut (Jubeen et al, 2012), peanuts (Adjou et al, 2012), almonds (Riba et al, 2013 and hazelnuts (Baltaci et al, 2012).…”

Effects of drying surfaces and physical attributes on the development of Aflatoxins (AFs) in red chilies

“…The main toxigenic fungi of concern are strains of Aspergillus flavus and A. parasiticus which can produce Aflatoxins (Chauhan et al., 2016; Hua et al., 2019; Iqbal et al., 2010b) although AFs (Aflatoxins) may also rarely be produced by A. nomius (Da Silva et al., 2017; Ertas et al., 2011). Contamination by AFs can occur in chilies and many other types of food, spices, dried fruits, milk, juices, tea, and feed commodities, especially in hot and humid regions of the world (Baquião et al., 2013; Ismail et al., 2020; Jiang et al., 2021; Murphy et al., 2006; Pallares et al., 2019; Zahra et al., 2018). As chilies are an essential part of everyday food in Pakistan, a continued exposure of the general public to AFs may have adverse effects on human health.…”