## 1 Introduction  
Aflatoxins, mycotoxins mainly produced by fungi of the genus _Aspergillus_, exert liver cancer-causing effects in humans and are classified as International Agency for Research on Cancer Group IA and 2B carcinogens [1, 2, 3]. Therefore, several countries set maximum residue levels for aflat in agricultural products and processed meat products, strictly enforce regulations, and conduct relevant risk assessments in foods [4, 5]. Consumers are exposed to the mycotoxins through infection with fungal strains during the pre- or post-harvest process, and Hazard Analysis and Critical Control Points have been introduced to prevent mycotoxin contamination and mitigate its risk [3, 6, 7]. Nevertheless, contamination with mycotoxins, such as aflatoxin, is possible depending on the consumption habits and agricultural product storage practice of each ethnic group, including Koreans. As a representative example, Korean doenjang is a type of fermented soybean paste made from steamed soybeans that have been dried in sunlight for a long time and aged under natural conditions. Notwithstanding, it exhibits high aflatoxin contamination [8; 9]. In this regard, various aflatoxin reduction methods, including ammoniation, are available, especially for agricultural products [10; 11]. However, in numerous cases, the global average or permissible aflatoxin content has been exceeded, and more efficient reduction methods are urgently required [8; 12; 13]. As a control measure, chemical fungicides are being used to directly sterilize aflatoxin-producing _Aspergillus_ spp. [14], and certain constituents of conventional fungicides are being developed for use as food additives [15; 16]. Aflatoxin detoxification has been introduced in the agricultural industry to minimize or remove aflat from agricultural products using microorganisms and enzymes [17]. The long-term viability of these approaches is a concern due to their incomplete effectiveness and environmental impact, especially with the use of fungicides to manage _A. flavus_ potentially leading to fungicide-resistant mold strains, environmental pollution, and risks to food safety, highlighting the urgent need for environmentally friendly agricultural practices aligned with food safety standards [18; 19]. Interestingly, biological control strategies have also been employed to control aflatoxin contamination in agricultural products. A successful example of a biological control method for _Aspergillus_ spp. is the fundamental blocking of infection by aflatoxin-producing _Aspergillus_ spp. using non-aflatoxin-producing _Aspergillus_ spp., as they become the dominant species during the cultivation of agricultural products in pistachio fields [20; 21]. The non-aflatoxin-producing _Aspergillus_ spp. used in previous studies is the _A. flavus_ AF36 strain, which is registered with the United States Department of Agriculture and is the first known aflatoxin biocontrol agent to be formulated and used in cotton seed fields [22]. This strain originates from Yuma Valley, Arizona [23], and is registered in the United States (US) as a biocontrol agent for minimizing aflatoxin contamination in agricultural product-cultivation fields, especially almond, fig, and pistachio fields [20; 24]. However, none of these studies have determined the extent of aflatoxin reduction via AF36 treatment in the field. In addition, as important yeast-based biocontrol agents, _Candida oleophila_, _Aureohasidium pullulans_, _Metschnikowia fructicola_, _Cryptococcus albidus_, and _Saccharomyces cerevisiae_ reportedly control diverse microbes owing to their excellent inhibitory effects, safety and registration issues, mass production requirements, ease of handling with various formulations, and applicability in the field [25; 26; 27]. Among them, _A. pullulans_ has been tested for the control of _A. flavus_ in vitro and on tomato plants, demonstrating a reduction in mycelian growth and the inhibition of spore germination [28]. However, the foregoing study did not consider reducing the aflatoxin itself.