Mycotoxigenic fungi contaminate cereals, nuts, fruits, and other food commodities, threatening human and animal health. This review focuses on Aspergillus flavus, Fusarium verticillioides, and Alternaria alternata as representative mycotoxigenic fungi because of their importance as food contaminants and their production of major food-relevant mycotoxins. Some methods detect fungal presence or toxigenic potential, whereas others directly quantify toxins. Fungal identification or detection of biosynthetic genes indicates presence or toxin-producing potential, respectively, but neither replaces direct mycotoxin measurement. The diversity of targets, toxins, and food matrices remains a challenge for accurate and practical analysis. Particular attention is given to immunodiagnostic approaches, including enzyme-linked immunosorbent assays (ELISAs), as well as complementary formats such as lateral flow immunoassays (LFIAs), and immunosensors, for laboratory and on-site food safety monitoring. The advantages and limitations of these approaches, with emphasis on sensitivity, specificity, matrix effects, and sample preparation, are discussed. Future aspects will focus on integrated, matrix-validated workflows combining robust sample preparation, multiplex recognition, portable readout, and appropriate quality controls to enable faster and more reliable monitoring of fungal contamination and mycotoxins throughout the food and feed chain.