Aflatoxin in Chili Peppers in Nigeria: Extent of Contamination and Control Using Atoxigenic Aspergillus flavus Genotypes as Biocontrol Agents

Abstract

Across sub-Saharan Africa, chili peppers are fundamental ingredients of many traditional dishes. However, chili peppers may contain unsafe aflatoxin concentrations produced by Aspergillus section Flavi fungi. Aflatoxin levels were determined in chili peppers from three states in Nigeria. A total of 70 samples were collected from farmers’ stores and local markets. Over 25% of the samples contained unsafe aflatoxin concentrations. The chili peppers were associated with both aflatoxin producers and atoxigenic Aspergillus flavus genotypes. Efficacy of an atoxigenic biocontrol product, Aflasafe, registered in Nigeria for use on maize and groundnut, was tested for chili peppers grown in three states. Chili peppers treated with Aflasafe accumulated significantly less aflatoxins than nontreated chili peppers. The results suggest that Aflasafe is a valuable tool for the production of safe chili peppers. Use of Aflasafe in chili peppers could reduce human exposure to aflatoxins and increase chances to commercialize chili peppers in premium local and international markets. This is the first report of the efficacy of any atoxigenic biocontrol product for controlling aflatoxin in a spice crop.

Present Status and Perspective on the Future Use of Aflatoxin Biocontrol Products

“…These are application of aqueous spore suspensions directly to the crop canopy or delivering the active ingredient through the irrigation system but evaluations in commercial orchards remain to be done [99]. The efficacy of aflatoxin reduction by atoxigenic isolates of A. flavus has been demonstrated in various crops including maize, groundnut, cottonseed, and pistachio in the US, and maize, groundnut, and chili peppers in Africa [48,51,91,100] (Table 2). Recently, efficacy trials have been conducted in sorghum in Ghana and sunflower in Tanzania and substantial reductions in aflatoxin have been achieved (unpublished results).…”

Use of Competitive Filamentous Fungi as an Alternative Approach for Mycotoxin Risk Reduction in Staple Cereals: State of Art and Future Perspectives

“…Regulations fixing the maximum content of mycotoxins in agricultural products, admitted or suggested, are applied almost worldwide as basic tools for consumer protection [26], and cereals, maize, and small grain, are included regarding several mycotoxins (Table 1). Aflatoxins (AFs), mainly produced by Aspergillus flavus [28], are a matter of concern in maize, as for many other crops, such as nuts (peanuts, pistachio nuts), figs, almond, chili peppers, sorghum, sunflower, cotton, typically in tropical subtropical areas [29][30][31][32][33]. Recently AFs have been for the first time also reported in wild fruit in Zambia [34].…”

“…The use of atoxigenic strains of A. flavus has been demonstrated to be significantly effective in reducing AF contamination in maize fields [12,94,100,101] and in other crops [31][32][33]102]; a mean AF reduction of around 80%, but also greater than 90%, in treated fields, was reported [12,41,103]. In addition, efficacy is enhanced in conducive conditions for A. flavus and AF production [104]; therefore, in more challenging years, with high AF contamination, the distribution of biocontrol products based on atoxigenic strains contributes significantly to making products compliant with legislation in force [105].…”

Technologies and strategies for aflatoxin control in Kenya: A synthesis of emerging evidence

“…Usage of Aflasafe products in Senegal (6 year data; Aflasafe SN01) and Nigeria (12-year data; Aflasafe) in multiple agro-ecologies and under diverse cropping systems has resulted in aflatoxin reductions in maize and groundnut of 82-89% (95% confidence interval) compared to untreated plots after storage or simulated storage conditions Above threshold (%) (Atehnkeng et al, 2014;Bandyopadhyay et al, 2019;Senghor et al, 2019). The product developed for use in Nigeria was also found to be effective to decrease aflatoxin content in chili peppers (Ezekiel et al, 2019). Data on efficacy of Aflasafe products developed and used in other countries (i.e., Kenya, Tanzania, Burkina Faso, Ghana, Malawi, Mozambique, and Zambia) is available but has not been published in scientific journals.…”