Mycotoxins are toxic metabolites produced by fungi. The ability to produce mycotoxins is found in some fungal pathogens of plants and molding agents of food and feed, and has a noteworthy repercussion on the quality and safety of food products. Mycotoxin contaminations present one of the most insidious challenges to meet in food safety. Their importance is evident in the constant attention paid to them internationally, because of their harmful impact on animal and human health as well as on the economy. The most prevalent toxigenic fungi on fresh fruits belong to the genera Aspergillus, Penicillium, and Alternaria, which pose serious mycotoxicological risks essentially in postharvest and processed food products. The use of microbial antagonists for the control of postharvest pathogens, including mycotoxigenic fungi, is briefly explained in this chapter taking into account the commercial potential and perspectives of the practical application of these biological control agents and their mechanisms of action.