Aflatoxin (a mycotoxin caused by Aspergillus spp.) in peanut (Arachis hypogaea L.) and other crops can have a major negative impact on human health. Previous research has been conducted to mitigate aflatoxin in the supply chain. However, documentation of adoption of proven interventions that decrease contamination by aflatoxin is limited in peanut. One objective of the research reported in this paper was to determine adoption of effective interventions for aflatoxin mitigation by farmers involved in a research project designed to quantify contamination in the field prior to harvest, immediately after drying, and following storage. A second objective was to compare adoption by spillover farmers (e.g., farmers not involved in the research project living in the same community as the research farmers) and a control group of farmers in other villages not exposed to the research project. The empirical study was conducted in Ghana from 2016 and 2017 to compare strategies to increase yield and reduce aflatoxin in peanut in five communities. Information on findings of the research were discussed among participating farmers and other local farmers through farmer field schools. Increases in yield and reductions in aflatoxin contamination were documented in this research and are reported elsewhere. Understanding concepts and implementing improved practices in the field, during drying, and in storage by farmers involved directly in research trials, farmers within research-targeted communities, and farmers in nearby communities without access to findings from the research were determined using a survey instrument near the end of the project in 2017 and 2018. Adoption of improved practices by farmers participating in the research and those of farmers influenced through discussions with participating farmers were often greater than a control group of farmers influenced by outcomes. For example, farmers in the research group and farmers gaining knowledge from the research findings dried peanuts on tarpaulins more than the control group of farmers. Farmers with greater exposure to the potentially negative impacts of aflatoxin on human health were less likely to consume peanut containing the mold causing aflatoxin and were more likely to discard contaminated peanut rather than selling them in the market.